if it's that much more costly, that won't be in our budget. Not to mention that I am having trouble rounding up folks to design an air to air mini-split system, I shudder to think of the blank stares I'll get if I ask for a geothermal system.

The later unfortunately is a west coast reality I am trying to fix. The best system on the market is Mishubishi or Dankin. Ask a distributor.

Air to Air works as long as it does not get too cold. You can use a ducted system with air to air. Just make sure all the ducts are the same length from the unit in the attic.

They are about five times more efficient than a typical AC. They are also more efficient than the Air-to-Air systems in the winter as they are depended on the underground temperature...

This is very interesting. What SEER and EER ratings for cooling and what COP values for heating would one expect to get from the ground source heat pumps you are referencing?

Sales hype and puffing, mike. No sense trying to decode or make real.

The best system on the market is Mishubishi or Dankin. Ask a distributor.

I find it amusing how, what, why & where people think something is better than something else.

Why do you suppose a distributor would say this? They aren't at all influenced by selling you what they carry?

Those systems won't require a good design, regular maintenance, repairs and eventual replacement like any other brand?

It's best because we carry it and have it to sell to you. (They selling you bro) That same distributor doesn't carry other brands they will tell you those other brands aren't any good? (again, they selling you) -- well who cares we have to buy something? right?

You know so you can clearly see the logic on the internet these days. I call it reading between the lines. What would you call it?

It appears that I found a couple of prospective HVAC designers to design the system for us. Since I could not find a single designer in the Portland area, I will be going the route of "remote" designers who were highly reviewed on Green Builder Advisor. I say "it appears" because aside from some initial emails, I have not been able to talk to either of them, and they have an eight week backlog. Isn't building during a building boom and supply shortages just grand?

This is not exactly what I had in mind (which was finding someone who can step in right away and help out before the house design is finalized), but beggars can't be choosers. I think we can make it work using a combination of soffits and closet installations for both the equipment and the ducts. From what I've been picking up in my studies, a couple/three ducted minisplit systems may be a good approach - but I will leave it to the designer.

Looking back at some of the earlier answers, I'm a little surprised by the criticism of no attic, and running ducts through soffits and chases. From everything I read, an attic should be the last place to run ducts (from efficiency, not convenience, standpoint), and ideally ducts should be run through conditioned space. Which is essentially what we'd be doing by adding soffits as needed. So I feel a little better about what the architects gave us to work with - though admittedly, had I known then what I know now, i would have started looking for HVAC consultants months ago. Live and learn.

Looking back at some of the earlier answers, I'm a little surprised by the criticism of no attic, and running ducts through soffits and chases. From everything I read, an attic should be the last place to run ducts (from efficiency, not convenience, standpoint), and ideally ducts should be run through conditioned space.

It's more like war of the worlds or old school science in combat with new school science. A choice or difference in how things get done. They say the world is changing and so people must change their old habbits and adapt... BUT?

Most of the time these things are created in "new builds" --- there's more than one way to do it. Some will cool the attic in which the ducts run in. The other way is to cut out the ducts and run refrigerant lines with cooling / heating heads that sit on the wall or in a cassette in the ceiling.

Efficiency is a "loaded" word. If you're dealing with these redesign issues with an older home with duct work in the attic most of the time the gain to "change" monetarily will not come close to the cost of "change". This is different for new builds... but efficiency gain thru not having duct work is one thing, the other thru proper refrigerant charge is another.

Some of this may not reach a level for you due to climate conditions etc. Efficiency gain or loss is directly tied to how much you use or don't use an appliance. So much of what I say in this post is from the perspective of someone who runs an air conditioner upwards of 10 months of the year most years... has duct work that runs thru a hot attic etc. (The house was built in the late 70's)

I'm still running the AC here and we're 5 days from the first day of old man winter.

The proverbial electric bill mine was total $42.83 last month. While square footage is a shade above 1900 sq ft. So to say efficiency is some greatly effected thing by running duct work thru an attic, it's entirely misguided.

How much money would I have to spend for efficiency and what would be the pay off from a $43 light bill? Maybe I would see a payoff in 100 years. Note: my system efficiency is mostly due to the system (equipment) installed. Duct work was replaced to R8.

build back better: somone is selling you because they have something to sell.

I find it more problematic to keep AC systems leak free (refrigerant leaks). Efficiency falls of a cliff with those. The more equipment you got? You'll eat thru money for the sake of efficiency. The newer refrigerants coming? much of the same... even when the solution is there --- but less money.

Money vs Efficiency... that's primarily the argument if you ask me. You know I have to have air conditioning where I live and while many say it's a crime to win these days. I still want to win. I don't "play" to lose.

Realize this is 27 years of experience talking. I'm sure there will be a "few" to chime in an bash this philosphy, claim I know nothing, say I am making it up or form a new argument possibly "non political" or any other method unto man to sweet talk you.

I'm not in the category of "sweet talker". You have choices, of those if the trouble gets to big to bear the box on a chunk of land gets sold and you move some where else incorporating some of what you learned. I see it all the time, even those with traditional AC's.

This isn't to say traditional ducts and HVAC equipment is some golden goose product that you won't have trouble with. Look at what I do for a living.... they all break. The more systems (equipment) you got the more frequently trouble will come.

No name brand, method, efficiency rating will over come that. The phrase "less is more" comes to mind. Ah well it's only money. -that's the other saying admitting defeat.

"Efficiency gain or loss is directly tied to how much you use or don't use an appliance."

Efficiency is not a function of how much an appliance or system is used. A 92% AFUE furnace is 15% more efficient than an 80% AFUE furnace no matter how much you run it--even if it just sits there. A car that gets 50 mpg is 25% more efficient than a car that gets 40 mpg even sitting in the driveway. The owner's return on investment and payback time are functions of the amount of time an appliance or system operates. It's an important distinction.

@Austin Air Companie Your comments about efficiency vs money would make sense if we were talking about whether it's cost effective to modify an existing system by moving ducts from unconditioned to conditioned space. But I'm building a new system, so unless the cost of running ducting in conditioned space is significantly more costly than running them in the attic, money vs efficiency is not the question - it is which approach is better.

From my reading, actual research shows that running ducts in an unconditioned attic results in about a 20% loss of efficiency compared to running them in conditioned spaces (https://www.nrel.gov/docs/fy10osti/48163.pdf). So I think running the ducts (and mounting the equipment) in the conditioned envelope makes sense for me - both for practical and energy use reasons..

@Austin Air Companie Your comments about efficiency vs money would make sense if we were talking about whether it's cost effective to modify an "EXISTING" system by moving ducts from unconditioned to conditioned space. But I'm building a new system, so unless the cost of running ducting in conditioned space is significantly more costly than running them in the attic, money vs efficiency is not the question - it is which approach is better.

Tupi2020, Yes I understand what you're saying... so let's put this into further thought...

The ductwork put inside the space or the conditioned aspects of the structure will cost more due to: room -- it will take away useable room with in the structure. What material will the ducts be composed of? If it's sheet metal that costs more up front to fabricate and install there is no degradation over time other than maintenance (dirt / dust in the ducts). If flex duct is used that duct work will break down over time. Typcially in the realm of 20-30 years, could be sooner if you have rodent problems that go unresolved for a time.

So you can argue what's better and it may be better for you, but not for someone else due to space required. Builders build and empty shell and say it will work like butter. Then you move into it and use it *sometimes* in ways in which the builder never imagined on paper.

If the duct work is enclosed and is the problem? If the duct work is in the attic and accessible?

There's this notion that there is this "perfect" way... Perfect for whom? One way or the other won't necessary divert you from trouble. The way I look at it is: Controlling that risk as much as possible. Whether the house is new or old... problems still occur with both.

From my reading, actual research shows that running ducts in an unconditioned attic results in about a 20% loss of efficiency compared to running them in conditioned spaces (https://www.nrel.gov/docs/fy10osti/48163.pdf). So I think running the ducts (and mounting the equipment) in the conditioned envelope makes sense for me - both for practical and energy use reasons..

20% of what? 20% of $43?

But before I replaced my equipment to inverter (duct work had already been replaced to R8 in the attic) My electric bill in same time period above with older single speed equipment was $69

Even $69 wouldn't be considered a "high" expensive electric bill here... for duct work run in a hot attic.

I tell you this because equipment choice and operation of such is typically just as important or more so than ducting in *some* situations.

You could argue my house is less than half the size of what this build will be... so would $86 be enough money to take away useable space within the structure? Realize this bill I get includes all. My house is an all electric home. I have no solar or anything making up the difference other than an Bosch Inverter heat pump and a traditional 40-50 gal electric tank style water heater.

I use what I can to show you in laymen's terms what efficiency really means to me money savings that count. Some of which is for you, the rest is for others that may stumble across this thread in the days, weeks, years to come.

I put these numbers on these things to demonstrate what the pay back would be for me in a hot climate... If you're just after efficiency for efficiency alone, not considering cost or savings? Why would you do that? Not saying you can't do it. All these things are choices of which will effect choices as time goes on good or bad.

If you choose mini split, traditional ducted HVAC with exposed ducts or enclosed ducts or ducts run thru a hot attic... none of these choices are absolute perfect. They are choices, that's it. Each one you will give up something whether it's space some efficiency and or problems in correcting problems after the fact.

The other consideration is my house was a drafty build. Built in late 70's anything built today will be much more tighter construction. I would say an *average electric bill* in my area for this time period would likely be at least double that of what I pay and in some cases even worse. Like around $100 or more.

So if you use that 20% figure again on $100, you're talking $20?

If I go to that same house and say: I can cut that in half by upgrading your equipment to Inverter? The expense to do as I suggest upgrading the equipment where as 9 times out of 10 the home owner will need new equipment anyway? save $50 a month versus $20 at much less of an investment than trying to put ducts in a conditioned space.

This explanation is to tell you that the savings in duct work is often times misconstrued because someone is trying to sell you something else. I've been in newer homes here in which the attic is a conditioned space, it's just a different way to do something. The problem with that method is: roof leaks?

Oh rip of the roof and replace it? Ok, when the roof deck ages and needs replacing then you'll also have to re-insulate that roof deck. So just choosing one method over another doesn't do away with what you're trying to escape... efficiency related to cost of doing one thing over another.

That's ok, we only live in our homes for 10-15 years then buy another new one. Yeah I've heard every argument in the book... trust me. wink~wink.

Note for clarification: The electric bill noted above was for November time period in Katy, Texas... considerably different from say July-August time period.

Where to locate ductwork in a structure is a question at the intersection of building science and HVAC. I think the building science considerations are missing from @Austin Air Companie's comments above. Let's look at a couple:

"The ductwork put inside the space or the conditioned aspects of the structure will cost more due to: room -- it will take away useable room with in the structure."

Not typically. Ductwork installed in a conditioned crawl space or conditioned attic doesn't take away any useful space. Soffits installed at ceiling level can be designed which contain ductwork and also add visual interest in the home. Unless you're planning on dancin' on the ceiling, I don't think a soffit takes away useful space. And the nicer the environment for the installers and inspectors the more likely the ductwork will be properly sealed.

There are other benefits gained from locating ducts in conditioned spaces including a reduced potential for mold/mildew growth.

"I tell you this because equipment choice and operation of such is typically just as important or more so than ducting in *some* situations."

That's not what the study accessible by the link provided by the OP indicates. Let's take a look at what the study researchers concluded for a typical one-story home on a slab foundation in Houston, TX--which, incidentally, is pretty darn close to Katy, TX:

Locating ducts in the conditioned space reduced peak cooling demand by 22% By contrast, increasing insulation in walls to R-19 yielded only a 7% reduction and upgrading from 13 SEER to 17 SEER yielded only a 2.5% reduction in cooling demand. If I've done the math right, that makes the effect of locating ducts in the conditioned space almost 10X the effect of increasing the efficiency of the air conditioner from 13 to 17 SEER. The associated reduction in annual electricity usage for cooling was 17% I think you folks in Houston have some issues with your power grid. If lot's of folks down there could reduce their annual electricity use for air conditioning, you'd be less at risk of your beer getting warm.

The study also showed that locating ducts in the conditioned space reduced the required capacity of cooling equipment by 24% verses only a 2.5% reduction by upgrading to R-15 in the walls, a 7% reduction for upgrading to R-19 in the walls, a 2% reduction for upgrading attic insulation to R-40 and a 2% reduction for upgrading the windows to ones with lower solar heat gain coefficients. A 24% reduction in capacity could result in smaller HVAC equipment and lower initial cost for the equipment--both at initial construction and subsequent replacements.

"I've been in newer homes here in which the attic is a conditioned space, it's just a different way to do something. The problem with that method is: roof leaks?

Oh rip of the roof and replace it? Ok, when the roof deck ages and needs replacing then you'll also have to re-insulate that roof deck."

While roof leaks can be more difficult to detect with some methods of constructing cathedralized, conditioned attics, that's not a reason to dismiss them as a method for insulating an attic. One way to minimize the risk and consequences of a roof leak is to invest in a roof with a longer life expectancy, such as a standing seam metal roof. Another is to construct a "cold" roof. Design is about optimization, which, by definition involves trade offs. My last home had a conditioned attic which put the 2nd floor air handler and ductwork in a conditioned space and gave us much needed conditioned storage.

"...save $50 a month versus $20 at much less of an investment than trying to put ducts in a conditioned space. This explanation is to tell you that the savings in duct work is often times misconstrued because someone is trying to sell you something else."

The study referenced by the OP wasn't sponsored by any manufacturer nor does it promote any brand of equipment. It wasn't "selling" anything--just reporting the findings. Interestingly, those findings were minimum additional cost to install ductwork in conditioned spaces and an outsized reduction in both required cooling equipment capacity and peak electrical usage.

The study referenced by the OP wasn't sponsored by any manufacturer nor does it promote any brand of equipment. It wasn't "selling" anything--just reporting the findings.

Sure I realize that... the old mantra if it's on the internet it must be true. People make blogs to sell commercials over topics they think will generate clicks. I know reading between the lines for some is quite the challenge.

I often take the road of devil's advocate to demonstrate that the choice you make "good or bad" has problems to consider. Things like choosing better materials for the roof. So let's spend more money for the sake of efficiency. If money is no object, it often chases no wins quite frequently under the guise "it's better". You're not doing it to save money... you're doing it to look better to strangers. OR what is your real reason _________________________?

I can tell you from a late 1970's build, I would never recoup those improvements from paying an average of maybe $60-70

Duct work takes no room if run in the attic and the attic is conditioned? Because the attic is conditioned how might the occupants of the home use this space? A builder doesn't think about things like that. They build, hand you the keys and they go off to build again.

If you don't have an attic or crawl space such as this particular house in question? It's back to the drawing board. You have to find room for it some where.

The $50K dollar question: Is this only about efficiency or is this about saving $$$ thru efficiency?

So again we don't know how important $50k is years later after this build is complete and problems start coming. They will come regardless of what you choose, some options chosen now will make those problems when they come less costly.

It makes no difference to me what people choose. I am not one to let a structure defeat me, but to say one method is better than another? Nope, it's a choice at the end of the day. Just as many or more problems with homes that have conditioned attics.

What is one sure-fire way to know you're still alive? you've got problems.

----------------

Reducing capacity of the system to save money:

Clearly you don't understand the nature of an Inverter AC. It only ever delivers the exact amount of cooling you need. 1% up and down stepping.

Let's ignore what Ray paid on his electric bill in a hot sticky climate (Katy, Tx)? $43?

So I do all this work... for more expense, to put in a smaller system? Now I have to pay for all this extra work and then fork over more money for a new smaller HVAC system for the sake of efficiency when my November electric bill is $43?

Why would I do that? How much might I save above from that $43.

20% so a big $8.60 a month. Wow, I can afford a big mac meal now every month. LOL.

"So let's spend more money for the sake of efficiency. If money is no object, it often chases no wins quite frequently under the guise "it's better". You're not doing it to save money... you're doing it to look better to strangers. OR what is your real reason _________________________?"

HVAC systems are designed to control the indoor environment. That's a tall order. It includes controlling the temperature, relative humidity, indoor air quality, and the comfort of the occupant(s.) There are a range of alternatives to choose from-- each with different initial costs, operating costs, and benefits. That's where a good HVAC designer comes in. The problem with this particular project is that the home has unique construction details which constraint the design of an HVAC system. The HVAC designer should have been on-board from day one.

So I took another look at that California governmental study of ducts running thru attic via the link.

It's a government study... so their problems in California is mostly related to "power consumption". With rates over 20 cents per KWH.

They chose pictures to put in there that were likely built before there was air conditioning and these homes were retrofitted to become conditioned. No where do they say anything of that. Those houses will continue just as they always have.

So with a electric rate of 20 cents per KWH, yeah you've got big problems. Especially with older homes that weren't designed for air conditioning. The same thing here in older sections.

Are these places going to tear down these structures and rebuild? So clearly you have to do some thinking outside the box.

Why is the price of electricity 20 cents a KWH or more in California? When in Texas the cost to produce electricity is roughly 4 cents a KWH before mark ups are added for delivery to the structure?

"So I took another look at that California governmental study of ducts running thru attic via the link"

The study accessible via the link the OP provided is "Ducts in the Attic What Were They Thinking?" which is a published research report of the National Renewable Energy Laboratory (NREL.) NREL is a laboratory of the U.S. Department of Energy (DOE) not the state of California. The study looked at homes in three cooling climates: Houston, Phoenix and Las Vegas. Those places aren't in California, either--at least the last time I checked. Indeed Houston, TX is really, really close to your home in Katy, TX so those data couldn't be any more applicable to your service area (he services the Katy, TX area.)

You'll need to find some other springboard to launch your California bashing, Ray.

Utility rates are quite similar to Texas from what I can see here.

click to enlarge.

So I think you can forget about California type problems right now.

The OP is building a new home, Ray. The study quantifies the benefits of putting duct work in conditioned spaces which was the point being debated. You don't need to read past the following sentence taken from the abstract to determine that:

"We present options for building homes with ducts in conditioned space and demonstrate that these options compare favorably with other common approaches to achieving electricity peak demand and consumption savings in homes."

From page 2 of that pdf link under tthe header "NOTICE"

Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof.

And there you have it.... back to the drawing board as it were.

The statement you reference is standard boilerplate for research reports which are not funded by a particular commercial interest. Credible research reports don't promote any specific product, service or manufacturer--unlike your oft-aired Bosch inverter endorsements.

ha, ha, ha, ha...

The whole study was a money grab that was "sponsored". Special interest groups looking for government money, then the government at the end doesn't even endorse it?

Ha, ha, ha... not on my watch.

Let's ignore those statements? sure go for it. It's your money do as you wish... The forum builder is for it... so just little HVAC guy me warning you. Heed it don't heed it? It's only money.

I'm not afraid to tell you bad news now, I won't be afraid to tell you bad news later. I go where the problem is... 9 times out of 10 -- you won't like what I find anyway.

At least you know how this may go before it even happens.

If it wasn't clear before, it's clear that Jethro Bodine was the smartest student in your graduating class.

Considering a failed 18 year Chemical Engineer decided to pound nails for a living?

Yeah quite clear, huh? Mr Ross?

Your apple doesn't fall to far from the tree of wisdom either. LOL.

"The problem with this particular project is that the home has unique construction details which constraint the design of an HVAC system. The HVAC designer should have been on-board from day one." BRAVO!

This was the only thing relevant said here buried in all the gibberish which could only be used in a script to a Grumpy old men sequel.

I'd call it a monstrosity of inefficiency derived from Idiosyncratic grandeur with little thought to function over design, but "unique" works too. Regardless of my personal opinion Tim is correct about HVAC design but the architect here is squarely at fault, and I'll quote @Elmer J Fudd stating in part "if you find a HVAC contractor who isn't busy there may be a reason" and I believe the same could hold true for an architect.

I could draw up the plans for a house like this on a napkin during happy hour, it's not hard if you let the trades try and make it work and not planned in the initial design. I've seen 2" holes cut through every 2x4 stud of load bearing walls to run waste pipe, and support beams and joists chopped out to run auxiliary stacks and duct work. Letting any tradesmen figure it out and they will hack the hell out of your structural members. This could be disastrous especially with TJI's, where hole placement and sizes are critical for structural support.

I deleted my prior comments for good reason, It's a train wreck left to the OP to figure out by the architect, with to many passengers stoking the boilers with nonsense to make bad design work.

Well hopefully the HVAC designer will be able to save this train wreck. If not, I guess we'll just ditch the plans and start from scratch :).

Any kind of structure can be heated and cooled. A good engineer or contractor will be able to meet your needs and provide alternatives for you to consider. It's peculiar your architect seems to have overlooked the need to accommodate flexibility of choices for HVAC in his work. It should be standard with any structure, especially homes.

Ignore Austin, you can see his style and attitude. He has no experience with the circumstances you're facing, he just likes to hear his own voice. Take a look at his internet-findable reviews to understand a bit more, he has plenty of available time in his workday for non-productive pursuits like long posts in this forum..

@tupi2020,

While the architectural design of your home limits your options for HVAC, you can explore mini-splits, high-velocity systems (e.g., Unico,) and radiant heating/cooling. It's not a train wreck; you just need an HVAC designer who knows their stuff.

Thanks for the advice @Elmer J Fudd, it's helpful. To be fair to the architects, they proposed the mini-split system fairly early on, and we (perhaps foolishly) agreed, seeing how they are so prevalent in most of the world outside of the US. So that may explain why they left no provisions for additional mechanical rooms throughout the house. Only after thinking about it further and getting more educated about some limitations of the ductless mini splits and multi splits did this plan start looking less than ideal.

I think a professional can design a combination of ducted and ductless mini-splits that will work well, probably with some soffits and maybe some rearrangements of the closets. i don't think it'll be too challenging.

Appreciate your helpful comments throughout this thread!

Ignore Austin, you can see his style and attitude. He has no experience with the circumstances you're facing, he just likes to hear his own voice. Take a look at his internet-findable reviews to understand a bit more, he has plenty of available time in his workday for non-productive pursuits like long posts in this forum..

Reviews are like disagreements on this board Mr. Fudd. You're merely a home owner getting involved in discussions like this that are clearly over your head.

Opinions in HVAC vary like the wind... I believe I have been fairly constructive in this thread listing various pitfalls of various choices. I haven't sugar coated anything to say that problems aren't escaped via one method over the other... only to say that based on my 27 year HVAC career, experience of actually doing this for a living you can cut your risk of problems by chosing other less costly options. If money is no object, sure ignore my warnings.

If someone is selling you something, especially in the HVAC space it's often told to you there is no downside to what you've selected... I've ripped those band aids off to tell you it's not so. I know you're not going to like the truth, so you may select to choose 50 other shades of grey. You can do that it's a free world with freedom of choice. That choice will have a consequence that is my only argument here in an informational way.

If someone such as me, says something someone doesn't like... whether on this board or a personal visit to their home? You know so you clearly see how "reviews" work. Reading between the lines as it were. The disagreements or bad reviews if you will were from people who weren't really my customer in the traditional sense. They were trying to "game" the system. When I wouldn't let them they retalliate via a bad review.

I give you an honest opinion up front lay things out in such a way there is really not a chance it doesn't live out to how I suggest. 27 years remember. How many flat roofs have I been on in that time working on HVAC equipment? How many homes with little to no attic space and HVAC system crammed up there?

Attics that are narrow? Two systems up there. One unit is dead needs replacing.. but you have to remove the other system to get the other one out. An architectural wonderment. People complain of the price... I tell them: call your architect or builder. It is what it is "after the structure is built". Common sense mostly in a world in which there is none.

How many times have I fixed builder grade problems in that time... some of which you never hear the story because? The problems were fixed. So when you have differences of opinion of people who actually know and do things other than those who like to poke and prod over things they clearly do not fully understand.

I took this thread to the max by listing potential utility rate information... to show monetarily rather than just pumping Efficiency standards. Sure the house is a new build, best to do what every efficiency standards are good, but at the sacrifice of maintenance costs, repair costs and eventual replacement costs?

As I said before once this house is built, the architect, the builder, the subs of that builder are long gone in typically a year or two at best. The warranty from the builder runs out. I don't do new construction, I fix new construction problems typically from 3 years and later.

Speaking of reviews you know good ones... every contractor has bad ones people who think they know more than those that actually do this for a living.

This home... from the review below was roughly 8 years old. You know to set the record straight from those that only like to "talk" with nothing to back it up...

click to enlarge.

Now if all you do is look for only good reviews? Good luck. There's likely a con man behind that platform.

I service the Katy, Texas area.

Clarification: I only post here in the mornings while I drink my morning coffee. The flip side of the coin: If I wasn't good at what I do, how would I have the time to do what I do?

You know some people just yack without thinking. Yet I have a purpose for everything I do. Whether someone likes it or not... well think about it. Do you not have a reason for what you do?

Reasons: Notice the above review said he read what I wrote here and elsewhere. He saw the political banter that went on in those threads. You think this person is the only one?

This post will stay here and live on in infamy. People who would rather get something done than get involved in politics of a forum board bent against the pros who actually work in this field.

Bread crumbs... if someone has a problem, 9 times out of 10 they need a pro -- not a home owner with nothing better to do than post Fudd. This isn't the bugs bunny / road runner hour.

@Charles Ross Homes "While the architectural design of your home limits your options for HVAC, you can explore mini-splits, high-velocity systems (e.g., Unico,) and radiant heating/cooling. It's not a train wreck; you just need an HVAC designer who knows their stuff."

Thank you for your helpful posts throughout this thread - I reread them a few times, and as I am learning more and more, your comments make more and more sense. Much appreciated. I will be signing an agreement with an HVAC designer/consultant this week to do all the Man J. S, D calcs, as well as lay out the system in the house, and do the necessary ventilation and make up air calculations.

@Austin Air Companie "This post will stay here and live on in infamy. People who would rather get something done than get involved in politics of a forum board bent against the pros who actually work in this field."

Ray, I did read all your posts and comments, and I appreciate the amount of time and thought you put into them. But I am still trying to decipher your advice to me for my project.

The repeated theme I see from you is that the ducts should be in the attic. As I said, I think that is highly debatable. It may be a convenience from the standpoint of servicing, but it certainly is not advantageous from the standpoint of energy use. I don't care to debate how much energy is wasted due to the ducts being in the attic - suffice it to say that we all agree that there will be some energy loss in ducts being routed in an unconditioned space.

I get your point about enclosed ducts being more difficult to service if/when the time comes. And yes, ducts will break down over time, what won't? But to make it sound like ducts have to be exposed for service seems a little far fetched. It's not like this will be the first house built without easy access to ducting - most multi-story homes, and apartment buildings and condos are built that way. I don't think we're doing anything groundbreaking here.

Don't forget also that there is an additional cost to building an attic - lumber is not cheap these days. So you need to add the cost of additional rafters needed to create an attic (material and labor) to the equation. That cost (even without considering the energy losses) may more than offset whatever service would need to be done on the ducts 20/30 years from now.

Re: Austin Air Companie

Mr. Fudd:

“Ignore Austin, you can see his style and attitude. He has no experience with the circumstances you're facing, he just likes to hear his own voice. Take a look at his internet-findable reviews to understand a bit more, he has plenty of available time in his workday for non-productive pursuits like long posts in this forum..”

Ray Austin:

“Reviews are like disagreements on this board Mr. Fudd. You're merely a home owner getting involved in discussions like this that are clearly over your head.

Opinions in HVAC vary like the wind…”

As I have said in other threads on this forum Ray, Elmer J Fudd is a self proclaimed ‘Looney Tunes’ Troll IMO. He adds little to the conversation except noise and sour negativity.

He adds ‘No New Technical Content’!

I have previously mentioned his vocation as a shoe salesman not to disparage how he makes a living, as it’s an honest living to be respected in its own right. I’m almost sure that if I ever did have the opportunity to meet Mr. Fudd that we would have a respectful, enjoyable and cordial encounter but as an HVAC technologist he seems to have no training or professional experience.

At least you and Charles Ross, ‘Cain & Abel’ as I like to think of you both in the Biblical sense, do add new technical content - even if you disagree with each other. I often find that I’m in agreement with both of you, as I see you analyzing the same situation from different perspectives. Sometimes there just might be more than one truth.

If you guys can just learn to harmonize you might have a future together as a musical duo.

How does the name, ‘Ray-Charles’ sound?

Merry Christmas, Happy Holidays & New Year to all - That certainly and unreservedly includes you too Mr. Fudd!

I do nothing more than offer a counterpoint when I encounter your often specious comments. You, on the other hand, are the one chasing me from thread to thread with insults. As with others, your tone, demeanor, and off-topic personal insults say far more about you than anything else. Don't expect any of your other comments to be taken seriously. I'm not the only one with that view, believe me. I'd report you but I'm happy for your efforts to undermine your own reputation and credibility here. With that, we're on the same team.

If or when you offer objective comments without needless BS or phony puffing about the topic being discussed, you'll find me agreeing with you.

"The repeated theme I see is that the ducts should be in the attic. As I said, I think that is highly debatable."

Ducts don't belong in unconditioned spaces. I don't think there's much debate on that point in the engineering or building science communities. Indeed, multiple studies have quantified the benefits of installing HVAC duct work in conditioned spaces. If they need to be installed in an attic, best practice would be to make the attic a conditioned one.

If you'd like additional information to supplement the link you provided, here's some others:

From Building America:

https://www.energy.gov/sites/prod/files/2014/01/f6/1_1g_ba_innov_ductsconditionedspace_011713.pdf

From Building Science Corp.:

https://www.buildingscience.com/documents/insights/bsi-074-duct-dynasty

From Energy Vanguard:

https://www.energyvanguard.com/blog/5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space/

From NEEA:

https://ductsinside.files.wordpress.com/2011/04/ducts-inside-training-manual.pdf

From the Zero Energy Project (ignore this if you're not open to eliminating ductwork all together):

https://zeroenergyproject.org/2016/12/16/place-ducts-inside-building-envelope/

I get your point about enclosed ducts being more difficult to service if/when the time comes. And yes, ducts will break down over time, what won't? But to make it sound like ducts have to be exposed for service seems a little far fetched. It's not like this will be the first house built without easy access to ducting - most multi-story homes, and apartment buildings and condos are built that way. I don't think we're doing anything groundbreaking here.

Don't forget also that there is an additional cost to building an attic - lumber is not cheap these days. So you need to add the cost of additional rafters needed to create an attic (material and labor) to the equation. That cost (even without considering the energy losses) may more than offset whatever service would need to be done on the ducts 20/30 years from now.

Well I did list the exposed sheet metal duct option. Those won't break down in your lifetime provided of course they are installed properly from the start. However due to cost as you suggest for residential those won't be cheap. But if cost is a concern now as you put lumber is not cheap... well things later on will likely not be cheap either. Of which I estimated in the 30-50K range in today's dollars depending on what you ultimately decide.

People like to put words in my mouth and say that I only believe ducts should be run in the attic. When I clearly gave you the option of exposed metal ducts in view or inside the conditioned space. Prior to me doing so, no one had mentioned that. Let's forget about that tho' much easier to forget than give credit to whom actually does this for a living. Gotchya.

People also like to say there's this 20% gain in efficiency and the cost to do this gain will pay you back? No they don't tell you that. So you can read all the info you want they will just quote you a number and much of this comes from la-la land in California where their utility rates are close if not the highest in the nation up over 20 cents a kwh in some areas only Hawaii comes close to those rates AFAIK. So in that realm efficiency this and that likely would have a payoff depending how important AC is for various areas in Ca. Mr Fudd's area in Ca no less: he waited 6 weeks to have air conditioning replaced. I don't know of anyone here in my area that would be able to wait that long.

Much of what you read from others that don't do this? Well I say you listen to them at your own detriment. How many 1000's of homes I have been in, repaired over the life of my career? A home owner is giving you info based on how many homes they owned in the past, present, future? This is the logic you're chasing...

The builder. He builds. He doesn't see half of what I see years later. A builder isn't "built" to do what I do. It may sound like I'm beating him up... but we need builders to build. The builder feeds me with work later on. Sometimes it's only 3 years and what is wrong in those 3 years? Varies like the wind. What did the builder choose or not choose to build the house? They work in the land of subs (sub contractors and general contractors)... bringing all these trades people together. Contractual Obligations. It sounds negative and it is in the sense that mistakes are often made. The builder often denies it. How do you think I know such things?

They will just pound you with link after link of resources to say hey lookie here or lookie there. The fact of the matter is there are rules and regs in building anything new. A builder has to do that. That doesn't make it "worth" what they say it is worth. That the cost will pay you back.

tupi2020, you had mentioned your desire to zone this house. So in that regard the access needed to duct work may happen sooner than you think. Also HVAC zoning in my professional opinion needs to be an elegant solution rather than just cramming that duct work in a chase or wall cavity with in the conditioned space.

HVAC zoning works, when performed properly. The picture I put further up about the HVAC zoning do over I did earlier this year wasn't an entirely smooth job as the reviewer said the weather was mild at the time of installation and couldn't be tested under a heavy heat load. That was a two story structure in which the zoned system a good amount of that duct work was in the conditioned space. I'm not superman I don't have x-ray vision.

I can tell you builders tend to over size ducts when installing zoning here. I can't say what they will do in your area. When you increase duct size over what it would normally be what happens?

Not so bad if only one zone is calling in a 2 or 3 zone system. But if all zones calling in a lengthy heat wave? I have a song for you... it's called "Trouble, Trouble, Trouble"

So why do the builders do this? they are only on the hook for 1, 2 years and oversizing duct work is far cheaper than actually doing it right. They talk a good game though. You need them and you don't have many choices outside of that... so it is what it is. I don't do new construction, I fix it after the fact, after the 1 or 2 year warranty from the builder has expired.

In some cases I've had home owners run back to the builder (prior to 2020, safe to say to forget about that now I think in most areas builders have more work than they know what to do with except for Mr. Ross I guess -LOL) --- but that same person that ran back to the builder ended up calling me a year or two later saying the same problems have returned and so I wound up doing what I recommended in the first place.

Then a shade over 5 years later they call me again, I go out there the system is hacked to death again by who knows and they couldn't fix it. Repeatable business is my game, nothing's perfect you're never done with HVAC.

Imagine how many more stories I could tell... it never ends. I actually love builders in the sense they keep work coming my way. So as I said before it is, what it is.

"Imagine how many more stories I could tell.." Yes, and those stories would be more tired, politically-slanted generalizations from a replacement HVAC contractor who doesn't even know what dewpoint is.

The average HVAC system has a life expectancy of 20 years or less, but the life expectancy of the ductwork should be some multiple of that. My last home, which was constructed in 1983, is on its third-generation HVAC equipment, but the ductwork is original with no alterations or maintenance except for zone control modifications. All duct work was placed in a conditioned space when the attic and crawl space were converted from vented to conditioned spaces in 2002.

While access to moving parts in an HVAC system for routine maintenance is a good idea, properly installed ductwork in a conditioned space doesn't need routine access for service; it has no moving parts (zone control dampers being an exception and they can be strategically located) the metal and flex ducts shouldn't be subject to mechanical damage, and the insulation isn't subjected to the high temperatures of an unconditioned space which would otherwise reduce its useful life expectancy.

The reports in the links (which contain real-world data from credible technical studies,) all reach similar conclusions. The Building America program, in particular, is about residential construction best practices which are economical both in terms of initial cost as well as operating and maintenance expense. It has cost data for the incremental costs to install ducts inside the conditioned space in a couple of case study homes. While material and labor costs are higher today, so are equipment and energy costs. The potential increase in energy costs due to any number of factors including environmental surcharges (e.g., carbon taxes,) conserving energy is worth some attention. For new construction, collaboration of the architect/designer and the HVAC designer early in the process will minimize the additional cost to install ductwork in a conditioned space--or potentially, eliminate duct work all together.

Improvements in any field are the result of exploring different alternatives to the status quo and implementing those which produce useful benefits for the user. Alternatively, you can make time stand still and simply do what's been done in the past. Sun dials still work, but most people prefer Apple Watches.

sure Mr. Ross. LOL.

You know as well as I do, you're looking to build new not fix what you built even 3 years ago.

The point being debated is whether ducts should be installed in conditioned spaces, Ray. I suggest houzzers will be better served if you stick to the issue, not attempt to divert it.

The point about having access to zone dampers and other electromechanical elements makes sense, I'll be sure to keep an eye out for that in the HVAC designer's design.

"Mr Fudd's area in Ca no less: he waited 6 weeks to have air conditioning replaced. I don't know of anyone here in my area that would be able to wait that long."

I know it's hard from your perspective to understand but in demand, highly rated contractors (of all types) have backlogs. Some generals up to 6 months or more.

To make it clear once again, I was replacing two existing furnaces that still functioned and installing AC where none had been in place before. It was in the springtime, there was no urgency. My priority was to have the work done well, not quickly.

Two contractors, one the lowest bidder, could start the next week. I waited for the better one and was very glad I did - people are busy for obvious reasons and also available for obvious reasons. And it was closer to 8 weeks. And, another thing you probably will wrestle with understanding, 4 guys showed up on the first day to do the work. Two of them worked exclusively on mastic sealing and re-insulating plenums and over 200 linear feet of hard ducts in crawlspaces. Nothing is in the attic.

Crawlspaces are not in the conditioned space though. This home in question is to be built on a slab with flat roof. Choices are going to be hindered one way or another with that "design" -- HVAC isn't a magic box.

You know, or you should know --- my line of work I don't get the choice as I am going to an already built structure. Whether the attic is conditioned or not doesn't matter to me personally. I go where the trouble is. If it's a conditioned attic and the trouble is there, I don't mind that.

So why all the rip roar fuss over conditioned vs unconditioned -- crawl space or attic either one?

Cost. You can talk efficiency all day long / percentages and so on. But when you start comparing costs what those things cost versus the dollar amount they will save?

Every location is different Mr. Fudd. Tell us what you pay per KWH for electric. So what works for your area due to costs of what you pay? Or take the attitude "who cares let's ignore that part of the equation" because this is going to prove Ray's point. And "WE MUST" at all cost not let Ray look right. He's always wrong no matter what he puts here.

That's what the fuss is all about. Efficiency is great if it has a monetary gain. Of course if money is no object, then you're just doing it to impress strangers.

Reading between the lines... I do it for you above. So you understand how to do it in the future.

"Crawlspaces are not in the conditioned space though."

Crawl spaces, like attics, can be either "vented" or "unvented" and meet the requirements of the International Residential Code. Sealed, conditioned crawl spaces are indeed in the conditioned space (thermal and pressure boundary) of a home.

"That's what the fuss is all about. Efficiency is great if it has a monetary gain. Of course if money is no object, then you're just doing it to impress strangers."

While you're looking at this from an HVAC standpoint, Ray, there are a number of reasons to construct a conditioned crawl space in lieu of a conventional, vented crawl space. That's the building science part. Our company has been designing and building conditioned crawl spaces since 1999. We've found that there isn't a big savings in energy cost, but there are significant benefits gained by minimizing the potential for condensation on duct work and other surfaces, minimizing the potential for mold/mildew, improving the air quality in a home, and maintaining conditions which are less hospitable for termites and other insects. Think "big picture," Ray.

lol. The big picture?

Cost vs Payback vs on going maintenance costs, repair and eventual replacement costs.

Let's forget about that though, better to just come up with a new argument.

"And "WE MUST" at all cost not let Ray look right."

I was going to retire from this thread but I couldn't let this pass without responding to this comment by saying:

Hey, no problem. There's no risk or concern on my part, you take care of this just fine on your own with your comments and the tone of your attitude.

.

Good luck to tupi2020, I hope you're on your way to a good resolution of this important problem that you identified.

Good luck to tupi2020, I hope you're on your way to a good resolution of this important problem that you identified.

Thank you, I appreciate the suggestions and thoughts on this thread, and will be starting with the HVAC designer in the next few days. I'll post back here with whatever design he comes up with.

I was going to retire from this thread but I couldn't let this pass without responding to this comment by saying:

Nothing that helps... yet you complain of my tone?

Show what your rates are for Electric. Let's put a dollar figure behind what you say and settle the argument. (We already know the electric rates of Oregon in this thread... you know my tone was so bad that I show cased them further up this thread.)

But you would rather not do that... because? I already know why, your answer isn't for me.

You can hide behind what others do not know. From there crunch some numbers your estimated length of life, how long you might live in this home... it's not a complicated formula to see if you're wasting vs being productive. Throw in estimated maintenance costs for the number of systems you have... you'll see.

My tone is what it is because, you would rather refute the truth for the sake of appearances... Mr. Fudd. Why Bug's Bunny always got the best of you. LOL.

It's only money... it's to be wasted at all costs for the sake of efficiency! (my tone again)

To update this thread, we hired an HVAC consultant to design the HVAC system for the house. After a number of iterations, we settled on three mini split units:

A zoned ducted mini split air handler in the utility room near the garage, serving the common area (great room, kitchen) on one zone, the primary bedroom suite on another zone, and the gym on a third zone. All ducting will be in soffits above the hallway.

We'll have another ducted mini-split above the guest bath area, serving the two guest bedrooms and the office (single zone).

Finally a third ducted mini split above the bathroom in the ADU, serving the bedroom and living room as a single zone.

While he made initial recommendations for the equipment, base don Manual J calcs, we'll likely revisit that after we select the windows and know the final U value. I also wouldn't be surprised if the HVAC installing contractor will propose a different approach, at which point we'll need to revisit the design again.

A recent article and discussion you might be interested in: https://www.greenbuildingadvisor.com/article/these-minisplits-are-not-getting-the-job-done?

@opaone A recent article and discussion you might be interested in: https://www.greenbuildingadvisor.com/article/these-minisplits-are-not-getting-the-job-done?

I read that discussion a while back, which is the primary reason we moved away from a house-full of ductless mini-splits, and switched to ducted systems.

GBA also has a good series on mini-split ducted air handlers - https://www.greenbuildingadvisor.com/article/planning-a-furnace-to-ducted-heat-pump-retrofit

"I also wouldn't be surprised if the HVAC installing contractor will propose a different approach, at which point we'll need to revisit the design again."

Perhaps revisiting what contractor to use may be a better choice should that happen. It sounds like you have a good plan, stick to it. Good luck.

It's been a long thread - I don't remember if I mentioned it, but I have a relative who bought a new unit - free standing but part of a developed neighborhood- that has a multiple zone ducted Mini split system. In a warm, primarily AC using climate. It works very well and the multiplicity of zones that are built into the hardware and work right, out of the box, is a great convenience. This one has two outside units, one for each floor. Each floor has several zones. I don't remember the equipment brand.

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@Elmer J Fudd Perhaps revisiting what contractor to use may be a better choice should that happen.

That's a good point!