@David Cary "What were you planning on using for the radiant heat? NG? When you could use solar to drive the minis? Or your baseload of hydro?"

I believe NG, and we did consider solar, but solar would be an additional cost that we can't manage. I really don't know what "baseload of hydro" means. Really need to speak with heating/radiant/HVAC expert. But as Thank you, David!

@Austin Air Companie, thank you for your advice. Now I need to research about the potential leakage issues with radiant heating. It would be a nightmare if it leaks. Can't we use one of those gadgets that detect moisture and send me a notification? eg: Samsung SmartThings Moisture Sensor? or any similar gadget?

Heat from any source rises, from floor to floor and from the floor to the ceiling. Rooms with high ceilings are hard and inefficient to keep comfortable in wintertime because so much of the heat will rise to the ceiling and out of the lower zones where people are.

With such a high ceiling, I recommend having one or more cold air returns up there and also a ceiling fan or two. High mounted returns are useful for both heating and cooling seasons in such rooms.

June - somebody said you had died. Good to see you alive and kicking.

OP: if your floor is installed correctly its not going to leak. People here use this kind of heat all the time. Let me just say that in the winter, the amount of glass we have turns that whole side of the house into a very cold black hole. Mini splits etc are just not going to do it. I think your architect probably knows best.

As for fans...yes we have them lol. But no you dont want them on all winter. Recirculate the air thru returns.

A radiant system heats the objects in a room, it radiates heat, while forced air heats the air, remember this to understand what follows.

The 17 foot ceilings on the 3rd floor will be a challenge for a forced air system with heat rising up those windows to 17 ft and then falling as it cools creating a natural convection current of drafty cool air in the living zone at the 4 to 5 ft level and you won't like it. If you want 70 degrees at the living level you'll have 90+ temperatures from 8 foot to the ceiling. Now you've created an uncomfortable and inefficient living space. For simplicity the rate of heat loss is determined by the difference of the indoor and outdoor temperatures divided by the R value of the envelope, and you're rising the differential 20 to 30 degrees the higher you get. With those big high windows with an R value of maybe 3 conduction will suck the heat out of the room fast.. Also if a heat load calculation isn't done properly your system my be under sized, running continuously and prematurely shorten the life of the system, so caution is recommended here.

A mini split on the 3rd floor is a ridiculous idea with those ceiling heights and any comfort will be impossible on the 3rd floor unless the windows are open, so forget it! Remember what I stated in the beginning? Here it comes.

The Idea of radiant heating in the 3rd floor is a sensible idea and should be considered. With radiant heat on the 3rd floor the temperature above the living zone will actuallybe lower by a few degrees because the system is heating objects and not the air, along with no or little draft. You will have better comfort 10 fold with radiant and an uncomfortable home sucks regardless of how new or nice it is. A proper tankless water heater for radiant heating in your area makes good sense and can also be used to supply domestic hot water to the entire house, dual purpose.

additionally chances of a leak with PEX tubing is rare, don't worry about it. Also there is no rule stating radiant heating needs to be in the floor, it can be in the walls, ceiling or using hydronic heating radiators. Radiators radiate as in radiant, and there are many designs on the market that are modern and thin that look and work great, no different than tubes in the floor to radiate heat. forget about mini splits on the other two floors and do forced air, the basement floor will be fine because I'm sure your state energy code requires 2" of rigid foam under the slab anyway, if not do it.

So how do you plan on fresh air exchange in your house if the infiltration rate is low? And Idea's how your going to maintain the humidity? I think you should seriously consider comfort as a priority when building a house and don't skimp to get other bells and whistles. Consulate a professional on the subject about heating and cooling is my last advice I will give, good luck.

OP: if your floor is installed correctly its not going to leak.

For a time, sure. The more time you have, the more time you use it... the less time you have until it breaks... leaks are a form of breakage.

If these kinds of things never leaked, there would be no methods to find the leaks.

It's costly to find the leak, if you don't hire the pro to fix and find the leak you pay for it by ripping up the entire floor, maybe you get lucky and this damage is minimal?

Moisture sensors are virtually worthless because you would need them everywhere thru out the floor to detect moisture. Because this is on the 3rd level, if a leak develops it could be a slow leak that then brings mold growth.

Here's a video on leak detection method... so ask yourself if these things never leaked why on earth would this leak detection method exist? You think a plumber is going to spend big $$$ on detection equipment to just sit on his truck and collect dust?

I disagree on the insulation comment. Our slab has been down for 2+ years, and we have 6" of foam under it. it is providing excellent insulation - even though our home is currently not climate controlled. Even in winter - the floor is a constant temp - same as the house.

Quantum mechanics and Radiant heating have a lot in common, people can spell them both but have little knowledge of either one.

A leaking PEX tube in a slab is easy to find and pinpoint in minutes using thermal imaging and a repair can be done in an afternoon by a professional. Good quality PEX is not going to mysteriously rupture on it's own, and almost all leaks are caused by sloppy improper installation or damage. A leak in an upper floor is easy to find even by an 8 yr old, and any problems seen from the 1960's to the 90's should be ignored because with today's advancements in the products any fears from the past are ridiculously primitive. Most leaks are at the connections and you don't put connections in slab installation, fire a contractor on the spot if you see it done.

When you heat objects, the air gets heated and then rises. I am not sure that I buy that radiant somehow fixes thermodynamic relationships. Perhaps improves them - perhaps not. A forced air system at least will force some circulation of air outside of hot air rising.

Baseload of hydro - The PNW has a lot of hydroelectric and is going to generate electricity - at helps perform "baseload" operations as opposed to "peak" operations. Your electricity is carbon neutral from hydro - the carbon was spent long ago. So using it is relatively green.

In northern PA here. We are doing radiant floor in the first floor only. the second and second-and-a-half floors will be conventional. the basement will not have radiant as its a well insulated basement and likely won't need much heat, if any, at all.

David there are 3 forms of heat transfer, conduction, convection and radiation. Air or water are mediums heated by a source through convection which will excite the atoms within the air or water and this energy will be transferred to objects it comes in contact with through conduction.

Radiant heating is different by the fact it requires no medium to transfer energy. It is thermal radiation that travels from the source directly to an object by means of electromagnetic radiation. The object will then transfer the heat energy to the air when it comes in contact with the object through conduction.

With energy as heat we're just moving it around from one form to another and using one of three different methods of transfer. The warmth from sunlight is radiant heat, the heat you feel from a camp fire 6 foot away is radiant heat.

As far as your second paragraph I have no clue what your talking about and feel lucky I don't.

kevin - I find it strange that you understand heat transfer and not electricity generation. Curious what your background is.

I understand the various heat transfer but I don't necessarily agree that it matters in this situation. The floor is 80, a fire and sun are not. All forms of heat transfer coexist and I don't think anyone thinks that a warm floor heats in the same way as a 500 degree campfire.

From US gov site

"Despite its name, radiant floor heating depends heavily on convection, the natural circulation of heat within a room as air warmed by the floor rises. "

"Your electricity is carbon neutral from hydro - the carbon was spent long ago. So using it is relatively green."

Electricity produced by hydroelectric dams is far from green and is probably the opposite. The construction of dams for this purpose destroys valuable fish habitats. On the Pacific Coast, that means salmon, which in its natural wild state has disappeared in many areas.

Few new dams have been built in recent decades, most are quite old. Other than dams needed for flood control, and excluding the very large ones whose presence is irreplaceable and politically unfeasible to change, many dams are being removed. And there is growing support for doing so much more aggressively.

A leak in a slab may be easy to find after you have figured out why the water usage has gone up during the past few months. I agree most leaks are due to poor installation. Unfortunately the typical homeowner has never seen a radiant floor installation and would not be able to tell if the installation has been done correctly.. A leak in a ceiling is much easier to find due to the water stains. It is easier and less costly to tear open the ceiling sheet rock than having to jack hammer a tile floor and concrete slab.

Elmer - agreed. But the dams are already there. But I agree with everything you are saying.

A central forced air, air source HP is probably the cheapest system you can install if a low installation price is the main consideration.

The missing link in hydronics until recently, has been the inability to effectively provide cooling in residential applications. While heat pumps have been around for quite a while they lacked ability to provide effective heating at low temperatures, that is up until recently. The advent of the ‘Low Ambient Temperature’ Air-To-Liquid Heat Pumps has solved these technical problems and now even challenges geothermal in some applications.

There is no reason beyond financial that all that you would like to accomplish regarding HVAC that cannot be done with 1 or possibly 2 Air-To-Water HP’s and having in-floor hydronic radiant heating, panel radiant heating and air-conditioning, central air-conditioning, domestic hot water (DHW) and effective zoning that can be as small as bathroom towel rack - and without short cycling.

This can be done in any climate requiring heating and cooling. Basement slabs should always be properly insulated otherwise you’re heating the earth! In-floor radiant is perfect for rooms with high ceilings. Unlike forced air where you have to heat the entire volume of air, in-floor radiant only has to heat the first 6-feet above the floor. This can all be done with highly efficient low-temperature hydronics supplied by an air-source Air-to-Water heat pump that can today come very close in efficiency to that of geothermal.

I have seen in-floor radiant done on every floor of a house and in-floor radiant installed in basements yet to be finished but planned for by at least determining the future layout for effective zoning.

If interested, I would suggest discussing this with a professional mechanical engineer that specializes in this field of hydronics and uses the latest energy efficient techniques both on the ‘Source’ side and the ‘Load’ side. The key to efficiency is to design using the lowest temperature water possible that meets design conditions for the greatest possible HP efficiency (COP).

BTW: Unlike forced air air-source heat pumps, Low Ambient temperature hydronic Air-To-Water heat pumps in most cases do NOT have defrost cycles where the house is air-conditioned during defrost mode and relies on high-wattage heat stripes to ameliorate the air-conditioning that you don’t want. Instead the energy to defrost comes from the large thermal mass of a buffer tank without the use of heat strips and with little to no detectable effect to comfort. This is yet another way that Air-to-Water HP’s approached the efficiency of geothermal without the installation of ground loops.

I would suggest investing in the most energy efficient system as opposed to ‘trying’ to reducing operating cost by installing solar panels at great expense hoping to feed energy back into the grid. Solar runs mainly on tax payer subsidies. Proper design generates saving by requiring less energy right from the get-go.

"A given volume of water can absorb almost 3500 times a much heat as the same volume of air, when both undergo the same temperature change.”

This is what gives ‘Hydronics’ its huge potential advantage - Think Water!

YMMV

IMPO

SR

Dave I'm offended you think I know nothing about electricity just because your written language was incoherent, off topic and nonsense.

Actually I'm quite proficient in electricity, in fact my profession required extensive knowledge on the subject. One of many jobs was with Baylor university maintaining 2000 ton chillers, absorption boilers for refrigeration, gas fired boilers for heating and heat reclaim turbines for the generation of electricity. I was employed as a maintenance electrician for K.D. manitou manufacturing to name a few but I'm retired now and really don't want to play with you or your nonsense.

Re: kevin9408 & Others

Kevin, if you're offended, then this would be a good time for all of us to tone it down so as to not offend and to not have this thread either locked down or deleted.

IMO

SR

"There is no reason beyond financial that all that you would like to accomplish regarding HVAC that cannot be done with 1 or possibly 2 Air-To-Water HP’s"

I added the bolding to the above.

fsq, you've reached a new level of double-talk. So you're saying that other than cost, he could hire 4 or 5 people as household help to spray water and wave fans at him and family members on warm days and to bring him frequently refilled hot water bottles to stay warm when it's cool.

I don't believe air to water heat pumps are very common and especially not in a mild climate area like the PNW. The cost of duplicative systems - water lines for radiant heating and ducts for air conditioning - are expensive, wasteful and unnecessary. You've said you live in Quebec or some other part of Canada with inhospitable weather, I don't know why you think what you see in your neighborhood is necessarily of interest elsewhere.

Why get complicated? This is PNW - the mildest climate in NA.

No, PNW has long winters that are cool (high 20s to low 50s) and damp and with short summers. The mildest climate in the US is coastal Southern California. Minimal heating and only occasional cooling.

I wanted to address the leak issue. The radiant floor is a closed system. You fill it with water, pressurize it and then turn off the auto fill. What this means is that there is no more water entering it during it's operation. It simply recirculates the same water around and around.

Your plumbing system for your kitchen sink, bathroom toilet, washer etc. is a pressurized system that if it leaks will fill your house with water and run all over the place. It has a much higher pressure than a hydronic floor heating system so there is more wear and tear on parts that are turning on and off like faucets.

If your closed system heating leaks it will depressurize and have a small amount of water that leaks out but then it stops. You will notice the heat isn't working, go to the basement and see that there is no pressure in the system and that will clue you in to look for a leak.

The radiant tubes that are buried in concrete are generally pex tubes. They exit the concrete and are connected at a manifold. If there were a leak it is most likely be at this manifold or someplace in the plumbing going to and from the manifold, not in the floor slab itself. The water in the floor system is dirty nasty stuff (rusty and dark brown) but it would be low in volume and not something that would flood your house or increase your water bill unless you have an idiot contractor who does not turn off the water fill on your closed heating system after it is pressurized. For sure where ever it leaked would have to be cleaned up.

You are much more at risk for having your house plumbing leaking at the dishwasher, toilet, under the sink etc. than you are from having your low pressure hydronic heating system leaking. Normal plumbing leaks are the ones you hear about running down the walls, flooding the basement and causing large insurance claims.

Your protection against this happening with your hydronic heating system is knowing that your auto fill should be turned off after the system is operating. We have had to educate just about every heating contractor we have had work on our system as they all want to leave it on which is unnecessary and foolish. A closed system does not lose pressure under normal operation and has no need to be back filled.

However I have to agree with those advising traditional for you.

Yeah for a moderate climate like Seattle... It's just not worth it.

Leaks, failures and possibly what causes them. I've done some research for you. Like it, lump it, leave it... I don't care. It's better than the alternative of chest beating keyboard warrior fanfare that often goes on in threads of this nature. He said, she said nonsense.

Base your decision on sound hard facts, not what someone said *WITH NO PROOF* as to what they are saying is actually *TRUE*. It's the internet anyone can say whatever they want. I choose to not waste my time like this.

Pex Plumbing Failures Information.

Pex failure lawsuit of 2005. Maybe things are better now, I know better.

You're hiring a builder... once the build is done, that puppy is all yours. The warranty the builder gives you if there is a problem... in most cases - stall, stall, stall, bs your way thru it until the 1 or 2 year warranty runs out.

In my 26 year career in HVAC I've seen this play out so many times... I'm calling it here before the foundation cures. Let's wait and see how it plays out. Cue final jeopardy theme music....

But it's easy to fix leaks. Sure so is pounding on the keyboard in a forum board. (fade to black)

Excuse me but 40 and 50 degree temps make a heating system worth it unless you like living in the 1800's. You make no sense, and those lawsuits were from products used in the 80's and 90's., things have changed. Everyone knows you DON'T use yellow brass fittings with PEX, you know right?

The way you talk we should all be using horse and wagons and give up on anything that breaks down. My 2008 Chevy Malibu was a POS I hated. I decided to buy another, a 2016 Chevy Malibu hybrid and I love it, even after one leg of the 3 phase inverter water cooling jacket leaked. It was fixed, pictures taken along with the parts sent to GM engineering. Technology evolves and products improve based on pass failures.

I prefer to live in the present and look forward to the future and not dwell on past failures.

I have a similar setup (3 total stories) in WI. We relied on our local HVAC engineers to tell us what would be appropriate, after I explained my wants. Ended up with radiant in basement/garage then full forced-air on zones everywhere else

I heated my basement and garage floors with radiant/water/boiler. It is awesome for the basement level, eliminates any "musty smells", I don't even need a dehumidifier down there at all, but it does noticeably heat the next floor up so we fight that. We "combat" the issue by just setting that "middle floor" zone temp lower in the winter, so while the thermostat might say 66 it will feel like 72. Forced air system still circulates air so in the end it just took some playing around to get it comfortable.

My opinion is I wouldn't do radiant heat under wood floors. My parents have had issues with theirs drying out their hardwood, which would "shrink" it giving them gaps everywhere. Granted they keep their radiant cranked a little high... Radiant on every floor does feel nice on the floor, but it makes it really hard to keep your room temperatures consistent since it's the "hot floor" that responds slow and the other systems battle. IMO it's best to keep radiant on pretty low and not expect it to be the primary heat source.

So me not wanting radiant throughout my entire house (95% hardwood, reason ^) I did want it in my upstairs tiled master bathroom. It was by far cheaper for me to have my flooring company do an electric system for that one bathroom, and also allowed me to keep that floor lower to match my hardwood height. It still has a "thermostat" on the wall, responds extremely quick to heat the floor to 80, and since it costs pennies a day to operate I just have it on the same programmed schedule every day.

Now for your situation, if I were you, it would depend on what flooring choices you want. Hardwood/carpet, I'd only radiant heat your basement. If you want concrete/tile, I might consider it everywhere... but again I'd run it pretty low and still rely on the other heat source for #1. It's a tough choice because once you have the system/boiler/etc in the basement, that's the expensive part and it's not much more to just run more pex upstairs.

I am not super familiar with the minisplit systems for heat - do they still circulate air like a traditional forced-air system? With modern homes being built so tight/efficient, I do worry about not moving enough air then getting mold/mildew issues. Then with this coronavirus crap today, I'd want to keep air flowing for health reasons as well. Just me thinking out loud here

I read the links and found them interesting. I always wondered if they wouldn't find that pex tubing on the potable water system contaminated the drinking water and the links seem to indicate that has happened.

When we bought our house, new homes were being plumbed with pex. I didn't really like that. I was very happy that our older custom house was plumbed with all copper for the water distribution system. However the sprinkler distribution in the basement used PVC. We had that all pulled out and replaced with copper because I didn't want any plastic on the pressurized water system.

We also have all copper on the in-floor radiant heating distribution system. The only pex is embedded in the gypcrete flooring. The snow melt uses a different type of tubing that is larger and has more expansion and contraction capabilities.

Many people love pex tubing in their water distribution system because it is cheaper to install and easier to work on. I think if I bought a house like that I may run a copper line right to the kitchen faucet with a check valves on all the other lines so that the water that ran through the pex couldn't mix with my drinking water. Does anyone else do this? Probably not. Everyone has their own priorities. I have read of people with PVC piping in their distribution system having that replaced with pex due to the failures.

My old 1970s house had aluminum wiring. The entire neighborhood did. I bought it for $150K and it most recently sold for $660K. There is no mention of them pulling all the wiring and replacing it. I never heard of anyone doing that in the neighborhood while I lived there. The problem with aluminum was if it was poorly installed and the builder of this neighborhood was widely known to build top quality homes. We did have to use specialized connectors when replacing fixtures or light switches. The homes in the neighborhood 60 years later are not burning down.

Even with copper piping you get one bad turnoff valve or fixture on the line that leaches lead and then you have high lead in your drinking water. We have had most of our shutoff valves on the potable system replaced with lead free valves and have tested the others with a lead test kit.

We hired a licensed plumber to replace the shutoff valve into the house along with some other valves that were older. He brought leaded valves. That is right, leaded valves to put on our potable water system. Luckily I had pulled one out of his bag to look at it before he got started. When I pointed this out to him he was horrified and blamed it on the warehouse that he buys the parts from. Fact is he didn't check and most people never would have looked at the markings on the valves.

My experience as a home owner is that the only reason I would not go with the architects plan is how hard it is to find people to work on the more exotic systems who know what they are doing. In the absense of that you have to really understand how your systems work so you can direct them to do the right thing.

A in-slab leak on the low pressure closed loop would not worry me at all.

As a plumber in Austin I'm sure you work on alot of people's homes with pex plumbing in the pressurized distribution system. I don't know how prevalent in-floor radiant heat is in Austin so can't imagine how many actual leaking slab systems you would have seen. In Colorado in-floor radiant heat is probably more widely done. I've seen it in homes built in the 60s on up but it still isn't common as it is more costly to install. The whole structure has to be beefed up to support the weight of the gypcrete flooring. We had our house inspected by a civil engineer when we bought it and he commented our steel beams are they type you see in skyscrapers not homes.

Also you only go around once. If the OP really wants to experience radiant floor heat then now is the time to get it. It is awfully special. We have had a number of people, mostly contractors, when they remove their shoes to work in the house say "wow, did you know your floors are warm?" The look of amazement and joy on their faces as their feet get the spa experience is something to behold.

However like anything else you get used to it and start to over look the wonderfulness of it. Both my husband and I agree that if we bought another home we would not prioritize radiant heat. We wouldn't run from it either but we would be fine with a conventional system. However that is said from a place of priviledge of having warm floors every day for the last couple of decades. We may sing a different tune if we buy a conventional system and have to wear heavy slippers again and can't run around the house in the dead of winter in shorts and t-shirts with bare feet like we do now. Also the dogs love it. Sometimes even we lay on the floor with them so as to get the spa experience.

Regarding the wall of south facing windows, ours used to be an oven in the summer. Melted the blinds, faded the cabinets etc. We installed solar screens on the outside that we can raise and lower with an electronic switch on the inside. They cut down on the heat tremendously in the summer. But in the winter we can raise them and get the passive solar which heats the house. Talk to your architect about this to make sure there is room to install them outside around the walls of windows. They mount above the windows and run in a tract down the side of the windows (to protect them from wind damage) and we have them bridging three windows at a time. They are really fantastic because you don't have to close the blinds to keep the house cool and can enjoy the view.

Thought I'd throw that in there since it seems your architect seems to have a similar design style to the architect who designed our house. We also have the three story open staircase that someone mentioned as a nightmare for heating and cooling. There is radiant heat in the landings but not on the stairs themselves. They are very cozy.

We absolutely love all the glass and windows. But there are trade offs. Eventually they had to be caulked and we had to hire someone to get up there to do it. It's probably coming due again and I plan to ask the window washers that we have coming next week to let me know if they see any that need caulking. Hopefully they are willing to throw in the inspection since they are up there anyways. They charge extra because they are non-standard, large and way off the ground. I usually don't have them wash the ceiling windows in the sunroom because we keep the blinds closed on them all the time and have solar screens mounted on the outside to keep out the heat. Sometimes I have them wash the skylights so may have them do that.

But all the windows is worth it. I can stand in any place in my house and get north and south light along with west or east light. Often also light above from skylights or ceiling windows. We surrounded the house with trees and beautiful gardens so you always feel like you are enjoying the outside even when you are inside.

Who won the "reward?"

Hopefully, the OP “won” with all of the advice to ditch radiant. And will win even further by giving serious thought to ditching the not so smart builder too.

I installed a Bosch Inverter Heat pump in my home around Oct 2019. The thing can produce heat down to 5F. While I have emergency back up resistance heat, I would only need it if the heat pump suffers a failure. (1800's extremely jealous)

That said, pretty much any regular heat pump can work well in a climate that doesn't get that cold for that long. Typically if you stay above 35F for most of the day the odds that you will need any defrost is remotely small.

Avg winter temps for my area is in the 40F's. It's a force air duct system. The inverter part keeps utility bills low. This heat pump creates more heat than I need. Before this addition I was considering in floor radiant heat. But the heat this heat pump creates adding a new system is over kill, unnecessary expense.

Bosch Heat Pump link (long read)

That said, I am not a plumber... nor do I service the Austin area. My last name is Austin, I service the Katy, Texas area.

In terms of my experience with plumbing: I have owned 3 homes in my life... one was sold long time ago. I currently own two, one is a rental. Both of these homes were built in late 70's time period. Upgrades, repairs, fixes to all systems with in these homes not to mention what I actually do for a living (HVAC) I have been in thousands and thousands of homes over my 26 year career in HVAC. Not to brag, but to tell you 'experience is your teacher'. I've got that experience in spades not only from my own homes, but also those that call me for service. I don't do plumbing professionally, as I am required to have a license for it to do that.

But HVAC requires me to 'know' plumbing as well as electrical as well as building related techniques & skills not to mention mechanical aspects of the heating and cooling trade.

I own my own HVAC company. Due to that I am presented the ability to 'choose' whatever I want in terms of a 'solution' to offer for whatever problem develops. In comparison if you call a company --- any company that shows up the representative of that company is likely shackled as to what they can offer you as a solution.

So because they depend on selling you something to get paid, they will gloss over problems... whatever they may be. Probably even worse when it comes to new construction because they build and move on. I'm not here to 'sell you' the points I have made in this thread -- the rebuttals to them make no difference to me. Everything I have stated in this thread stands.... ultimately the choice is the OP's to make.

I chose what I chose primarily for 'cooling' the little heating I needed was a big fat bonus.

I service the Katy, Texas area. I am licensed for HVAC (cooling and furnace work only)

kevin9408 Thank you for your advice, Kevin. I will definitely speak with the professional regarding the fresh air exchange. The reason we are considering the mini split is due to the fact that my spouse has severe allergies and don't want any ducts in the house, not to mention the extra cost of installing forced air system in addition to radiant.

JJ, I've been away and haven't had a chance to review all the posts, reading it now and am going to determine who won the "reward" I figure most people would like a Starbucks gift card for a drink or two?

Who wouldn't?

@sprink1es and @mmmm12COzone5, Thank you so much for sharing your experience. @David Cary, @fsq4cw , and @Austin Air Companie, thank you for your advice, and it shows that I have a lot to research and learn. I still haven't decided 100% what to do. I'll need to speak with local heating and AC companies. Some of the posters' advice was very inspiring, but didn't suit my situation due to the cost issue. I would have to say that mmmm12COzone5 has won the reward simply because she has shared her experience of living at a house that's very similar to the one we are building. I'll PM to send the Starbucks card!

@mmmm12COzone5 I PMed you regarding the "reward".

We have decided to install radiant heating for the basement and the top floor combined with a supplementary mini split system. No ducts due to my family's severe respiratory allergies; we can't have moving air. Some commenters on this thread mentioned newer and better technologies, and the Austin plumber recommended the good old air forced system, but after weighing the costs, pros, and cons, we decided on the hydronic radiant and mini splits.

Now I have to decide whether to install a ceiling fan for the really high ceiling. Personally I hate the look of the ceiling fan, not to mention the additional cost. Our allowance for heating/AC is $45,000. Yesterday, I contacted a bunch of heating experts to get an estimate as to what I could get with that budget, but none have called me back yet. Our GC told us today that with our budget, he could install radiant on both the top floor and the basement and use the same pump system. Though I am glad that we could have radiant on both floors, I find it disheartening that originally, he told us that he could do radiant just in the basement and installing it elsewhere will exceed our budget. ONLY AFTER we pushed back, and told him we want it on the top floor, now he's saying that he could install in both floors. If we didn't question him, then he probably would have just installed the radiant in the basement. That would've been bad.

So far we have the foundation/cement component poured. We asked him for the list of subcontractors that he will be using for our house, and he said that he has a lot of them, and sometimes, last minute, the subcontractor he uses may change. On his GC builder's contract we had reviewed by an attorney prior to signing, it clearly states that he will be giving us the contact info of all the subcontractor. Currently, our GC is getting the money directly from the bank (who's financing our custom house), and I am thinking that I should be more involved and know exactly how much our GC is paying who, so that I have better insight. I have lost a bit of trust with my GC due to what has transpired with this radiant heating issue. So much to research, think, and decide. . .

Thanks C.J. S. for the gift card! Good luck with your custom home! I'm sure it will be beautiful.

Thought I'd throw in $.02 on the ceiling fan. We have a really high big one with all sorts of programmable features (dimming, speed, timer, wireless remote etc). While we have used it (mostly for drying the floor after it has been washed) we don't really use it for part of the heating or cooling. Next to it, above our two sided cat walk, we have a compact cassette mini-split. It throws out the cold air in all directions so that takes care of the cooling. In the winter the floors are heated on the catwalk and on the floor below so all the heat is right where you want it at your feet.

Plus it is a pain to clean. And we have to hire people with special ladders to change the light bulb or clean out the light fixture that gets dead bugs in it. The ladder has to be a very tall inverted V shaped ladder since there is nothing near it to lean an extension ladder on. Almost no one has a ladder like this except painters. That is who I hire to service it.

All our bedrooms have ceiling fans. Don't really use those either except for the light feature on a wireless remote so I can turn the lights off while in bed and on in the middle of the night with the dimmer feature to get up and use the restroom. So if you don't like ceiling fans I would skip them. Go for wireless lights and whatever smart home features you want.

The ceiling cassette above the catwalk is a breeze to clean since it just requires a normal step ladder. Try to locate all your ductless minisplits in locations where you can get to them with a ladder you can manage. We have one smoke detector that is 3 stories up and needs a 24" extension ladder to change the battery. We have the 10 yr lithium in there but my husband is never pleased to be hauling that monster ladder into the house when the thing is beeping in the middle of the night and scaring the dogs.

I'm sorry C.J.S. but you need air movement in the house FOR health health reasons and by code. With your family's severe respiratory allergies as you claim, you must take active involvement or end up with substandard air exchange, filtration and a conditioning system that could risk the health of those living in the house.

Settle mechanical code chapter 4, ventilation- dictates what the requirements are.

http://www.seattle.gov/documents/Departments/SDCI/Codes/MechanicalCode/2015SMCChapter4.pdf

You will be required by law to have air movement in the house, and with the health concerns you stated do not let the GC decide, you need better than minimum equipment.

Settle is one of the most humid cities in the united states, fungus and mold love humidity and you'll need to control humidity. You'll also need a HEPA filtration system for the fresh air that is exchanged with the old nasty air in your house to remove pollen and spores along with the dust and these systems require ducts.

I really do not think you can get away without ducts of some sort in your new house.

Just to throw in an agreement by example - hospitals have a lot of ducts. And a lot of air movement.

Given the concern for mold in ducts, wouldn't a dehumidifier be a helpful tool?

I still find radiant in a PNW basement overkill. The heating load in a mild climate new house basement is very close to zero. The mechanicals generate some heat - in your case presumably the hot water heater and the boiler for the radiant - and the heat loss is so small. But the humidity is significant - and radiant doesn't do anything for that. A mini would of course.

So what is your humidity plan? I can think of zero way of removing humidity without moving air. And of course, minis still "move air".

The inside of a new house is loaded with VOCs - what is your plan to remove them?

Random internet quote:

Volatile organic compounds (VOCs) are one of the major ambient air pollutants and are emitted from diverse chemical sources in common daily use. Exposure to VOCs may cause upper and lower respiratory symptoms and contribute to the worsening of asthma.

I don't know anything about air movement per code, but all builders in my area (WI) talked about with homes being built so "tight" these days (insulation), moving air is incredibly important to prevent mold and mildew since houses no longer "breathe" like they used to. VOC's, germs from humans sitting, dust, etc are all further examples of why air should move and be filtered

This is why it's wise to let systems be engineered by a hvac professional. There are always "above and beyond" filtration methods that can be done

To be fair - not sure how many systems are "engineered by a hvac professional". I would suggest an outside engineer doing the design. I haven't been terribly impressed with "hvac professional" and they aren't getting graduate degrees in HVAC design.

@David Cary Yes, that's a great idea. I wonder what kind of an engineer would be best, and what their advice would cost. . . I will install a dehumidifier in the basement. I agree that in the Pacific Northwest mold and mildew is a major problem, especially in the basement. Thank you everyone, I will definitely have to think about air exchange and air quality.

@mmmm12COzone5 Experience matters! I never thought about the difficulty of reaching high smoke alarms, etc. Thank you, I'll definitely make sure things are more accessible. What kind of floor do you have with your radiant heating? Tile, concrete, or engineered wood? Do you happen to know what type of floor is the best?

@kevin9408 Wow, so much to think about. Thank you for pointing that out. I will have to makes sure that we get a great HEPA filtration system. Any advice on what type, Kevin?

@sprink1es Yes, air filtration without ducts could pose a major challenge, but I really want radiant floors. . .

Based on this article: https://www.thisoldhouse.com/green-home/21014891/whole-house-air-purifier I don't seem to have much options other than portable air purifiers. I'll do more research, but curious about how @mmmm12COzone5 circulates the air since she doesn't have any ducts in the house. Surely, there has to be a better way to purify the air without ducts? Or maybe that mini split system could somehow exchange the air? Maybe something like this? https://www.rgf.com/products/air/mini-split/ or https://www.skylandsenergy.com/ductless-heating-cooling/ductless-mini-split-indoor-air-quality

We have wood look tile on most of the main floor. We put it in 18 years ago and I still love the look. The larger stone look white tiles with light grout, I don't like as much because the grout has been a pain to keep clean. Slate look tile also ages well due to dark grout.

Pros of tile are that it is hardy, easy to deal with dogs and clean ups. Hard to damage. Cons are hard to replace if damaged, grout is annoying and cracks at the expansion points between room pours of the gypcrete. And it is hard on your feet.

If you get tile make sure they have a expansion line at the doorways that has flexible caulk and not grout. For grout get the premixed kind that doesn't require sealing. Better yet get epoxy. We found the premixed kind cracks less. The problem with tile that spans across pour areas or from one room to the next that is on a different heating loop is that it expands and contracts at different rates, thus cracking the tile and grout at doorways.

We have had two rounds of carpet. The first included radiant floor rated rubber pad and low pile berber carpet. This was perfect and transmitted the heat well.

When we replaced it we got the current version of the radiant floor rated rubber pad and a thicker plush carpet. The plusher carpet does not transmit the heat as well. The same manufacturer rubber pad (just their current model) stunk for 5 years of rubber. It was really bad at first and got better with each year but was just noxious. We had the manufacturer rep out and of course he couldn't smell it. For years we aired out the house at every opportunity and kept those bedroom doors closed 100% of the time unless we had all the windows open.

It was strange because the first version of this same pad had no odor at all.

We also have tarket fiberfloor in a bathroom. It is soft and easy to lay but it is easily damaged so good for low use areas.

If I could go back in time I would have used a sheet linoleum like I had in my old house. It was a solid surface (color all the way through) sheet flooring and not the printed picture under a piece of thin plastic type. It may have been commercial grade but I'm not sure. I got it as a remenant and the installer loved it so much he stole the left overs to use in his own house. We didn't put it in because we didn't think it would be high end enough looking. But after dealing with cracked tiles, grout cracks, grout coming up and stinky carpet pad for years I would have loved to have gotten what was practical and let the next owners worry about looking posh.

In terms of finding a hydronic professional look at who is teaching the on-line seminars for installing hydronics. Contact the people you are impressed with and see if you can hire them or if they have a recommendation.

For instance this guy:

https://www.youtube.com/watch?v=raHCtObGOhY

I highly second finding someone who specializes in this to design your system.