Contractor 4 just left and quoted 5382 for the Trane XL14c gas/electric and 6012 for the dual fuel. I liked this contractor probably second best out of all of them.

frangione

what size pkg unit are you replacing? for what size living space?

you are being quoted a two ton? correct?

I like Contractor 1. The Trane XL14c in both dual fuel and straight gas/electric have a var speed blower which is a big plus. I like the dual fuel which I est will save you apprx 25-30% when heating your home in HP mode vs nat gas. The cost difference will easily be recovered in a short time and I would expect electric rates for NC will be more stable than nat gas rates.

I would get HW VisionPro IAQ stat. It has "dehumidify on demand feature" for AC comfort and Trane offers nothing close to it.

I am attaching fuel comparison calculator.

IMO
Good LucK!

Here is a link that might be useful: Fuel Comparison Calculator

It is a 2 ton unit. The downstairs is 1000 sq ft. The upstairs, which is controlled by a furnace/fan/coil system with outside remote compressor is 1200 sq feet.

I estimate (based on your 30% and assuming 70% of the gas bill is for the downstairs as it takes more heat load) that it would take me 7 years to start realizing savings, given the higher up front cost, and assuming gas rates don't go up a ton. Our gas bill for the winter last year was less than $400 for all 5 months. I am struggling with whether this is worth it. Everything in this house is original, so 15 years old. So we are expecting to have to replace the upstairs unit (which I think I would do straight heat pump for), the roof, water heater, etc. So I am trying to weigh all of this together. I don't know how long we will be in this house. If I knew we would be here 10+ years, I would definitely do the dual fuel.

Based on the calculator you gave me, assuming a COP of 3.4 (don't know if that would be right or not, ust did a quick search?) we would see savings in 3.5 years. The default COP was 1.7 and at that, the heat pump was slightly more expensive than gas.

frangione

either way,the XL14c is a nice unit.What is the BTU output on the gas furnace side? That's a two stg. You should be aware that Trane's sister company AmStd offers the same mdl and may actually be less expensive. You might want to check with AmStd dealer. just an idea.

I also live in Southeast. and have a dual fuel system.

And while I know people do it every day, I think an 80% eff furnace is a dinosaur unless paired with a HP even for our area. Keep in mind for every $100 spent on nat gas, $20 is waste.

I made a quick calculation and believe the difference for dual fuel can be recovered in three to four years and of course you should see some minor savings on the cooling side.

IMO
Good Luck!

Here is a link that might be useful: Heritage Hybrid Comfort System 4DCY4

the BTU output for the furnace portion is 48000 first stage and 64000 second stage. I think I should have pointed out that the $400 I quoted includes the upstairs heat, which is separate. So less than $300 of that would be for the downstairs (I don't know how much higher the heat load for a first floor). Did you take that into consideration for your calculation?

How does the american standard unit compare to the trane?

frangione

first I would recheck those BTU numbers for gas. Whether those are input or output numbers, that would be way oversized for a 2 ton in a Southeast location.

No I misunderstood about your nat gas usage but I still would expect a payback against the cost difference of no more than five yrs. Certainly worth study and consideration.

Trane and American Standard are sister companies,same as Bryant and Carrier. Except for cosmetics primarily cabinetry, the units are identical including warranty. I would not turn around for the difference whether straight gas/electric or dual fuel. Cost and contractor would be the determining factors.

Trane gas/electric XL14c 4YCY4024
Trane Hybrid dual fuel XL14c 4DCY4024

AmStd gas/electric 4YCY4024 2 80.00 14.00
AmStd Hybrid dual fuel 4DCY4024 2 23,600 14 8

IMO

I don't have an answer for you about the btu. I thought that is what was being referred to on one of my estimates. I couldn't find the info on Trane's website...

What did you mean by "I would not turn around for the difference whether straight gas/electric or dual fuel"?

What is your opinion on the extended labor warranties?

"What did you mean by "I would not turn around for the difference whether straight gas/electric or dual fuel"?"

Frangione

This is what I meant. Whether the gaspak or dual fuel, the Trane and AmStd mdls are basically the same and either would be acceptable. I would let the cost and comfort with the contractor be the determining factors.

I have the ext warranty on my Trane four yr old system and as of yet have not used it. As a general rule of thumb, the cost is about 10% of the installed price of a new system. It's nothing more than an insurance policy. It leaves a bad taste though to be purchasing a new system and then to buy the ext warranty.

I still would recheck those BTUs on the gas furnace. Even at 80% eff, they seem high especially for your climate.

IMO

I am confused about the BTUs. Isn't this dependent on the equipment and the tonage? I was quoted for 2 tons, and 2 tons is what our old unit is and load calculations said that is what we need, too. If I can't find the info on the trane website, I don't know how I am supposed to check the numbers.

frangione

call your dealer's salesman or perhaps refer to a brochure. package units are sized to cooling and what will sell the most on the heating size. Both Trane and AmStd should have this on their site but in fact they don't.
not a big deal other than you will never use second stage gas heat unless NC goes into a deep freeze.

IMO

American Standard lists 2 tons and 23600 capacity for their hybrid. I don't know if the capacity is for cooling or heating?

One of my quotes lists 60000 btu input and 48000 output and one of the load calculations lists a heat load of 38000 (I assume this is just the first floor).

Trane has a $300 rebate offer right now, so I am going to assume that will negate most savings on the american standard. I would like to make a decision as we currently have no heat and the temps will be dropping next week.

I appreciate all of your attention to my posts. I will probably go with the dual fuel. If we move soon, oh well.

frangione

that 23,600 BTUs is cooling output.

12,000 BTUs=1 ton
24,000 BTUs=2 tons

as said previously, either the XL14c gaspak or dual fuel will do a nice job for you. don't worry about the BTU output of the gas furnace-you will never use the second stg unless NC goes into a deep freeze. I would though ask the salesman to confirm the output BTUs.

yes,I was looking at next wk's forecast and it looks like a light freeze by tues/wed so you better decide and get install scheduled. I assume this is a one day install. correct?

I do recommend the HW VP IAQ stat with outdoor sensor and set changeover pt at 35 deg if you go dual fuel.

Let us know about your install and initial impression of operation. A very nice unit which should provide good service and comfort for your family.

TD
Good Luck!

Thanks. I pulled the trigger on the dual fuel unit and have an install scheduled for Monday. We got lucky because someone had to reschedule their install which opened the Monday slot for us. I am geting the HW IAQ. The installer I chose always uses that tstat, says it is the best. I will let you know how it goes. It is a one day install, so we should be ready for the cold weather.

frangione

good timing on install...

one other thought. you have a central return on first floor and change filter out once/mth?

Congrats!

TD

Not familiar with all the lingo, I assume you mean the intake located indoors? I do replace the filter, but not that frequently (more like 3-6 months). I will definitely be better about that stuff with the new system.

Thanks again for all of your help.

frangione

I would ask installers to make at least a cursory inspection of your ductwork if they haven't already.

I assume you have at least one central return for first floor. these filters should be replaced on a regular basis to have good indoor air quality, protection of evap coil and blower, and to have good airflow to all rooms covered by this system. filters should not be too restrictive and I suggest you ask dealer for recommendation. changing filters on a regular basis is just good practice and cheap insurance.

IMO

We have one return on each floor.

Two of the four contractors that gave me quotes did very thorough inspections (thorough being more than just a quick glance) and said the ducts were good. I will have the installers look over them again. They will be putting in some dampers anyway as we have problems cooling/heating one of the rooms (large room with cathedral ceilings, skylights and faces west).

frangione

dampers really will be of little value. you need either another supply run to this room which is best choice or second choice a larger supply run. in other words, more CFMs to this room. it works and will make a noticeable improvement for comfort both cooling and heating.

TD

Thanks for the info. They aren't charging us extra for the dampers, so we will have them do it anyway and see what happens and deal with a larger duct later. How do you know how much larger the supply run needs to be? I think it currently is 9 inches.

The dampers are better than nothing in my opinion, but as tigerdunes noted, typically more extensive ductwork modifications are needed to fix a deficient ductwork system (i.e., poor airflow).

frangione

it is very common for rooms with high cathedral type ceilings to be undersized on ductwork. shouldn't happen but it does.

I am by no means a ductwork expert but I believe that's about 350 CFMs on a 9"??? which is less than a ton of conditioned air. also depends on distance from the main supply trunkline. salesman really should have performed a man j heat/cool load calculation to properly size your new system. your problem raises the issue of whether a 2 ton is correct size for first floor.

the dampers can marginally help in rediverting conditioned air but keep in mind you can only get a specified amount through a certain size ductwork. that is why I suggested another supply run for adding additional CFMs. as long as ductwork and location of another room register is accessible, then this is not necessarily a big deal or very expensive.

Your question. "How do you know how much larger the supply run needs to be?" Salesman should perform a man J broken out by each room with special attention to your large room. he can then readily determine the amount of existing CFMs vs what his measurements call for. it's that simple for an experienced person, not so for a salesman only replacing existing equipment.

if this was my home, I would try to answer these questions while you have the dealer's attention. now,not later.

if this issue was known by salesman up front, then a good salesman would try to find out and address problem with solutions. dampers though will not help if you are short on CFMs.

IMO

When I first started getting quotes, I had never heard of a man j calculation. One of the contractors did a load analysis and gave me a copy of the calculations. I don't know if it is a man j calc or some other kind of calculation. I don't see anything to suggest that individual rooms were analyzed separately, just listings of windows, directions they were facing, sun/shade exposure. These calculations said a 2 ton was enough. I did want to point out that it is just the one room that has cathedral ceilings, not the entire downstairs. It only has 2 vents and this room is on the opposite side of the house from the unit, but the duct goes straight from the unit to this room. But, the other split-offs for the other rooms occur first. I mentioned that the room was hotter in the summer and 3 of the 4 contractors suggested dampers. Only one of those 3 also suggested increasing from a 9" to a 10" duct, but did no calculation to arrive at that suggestion. From what I have heard on other forums, it is very common for people to not do a man j cal, so what am I to do? It is too late to cancel the install, but I can try to discuss the ducts some more. I'm just not sure how far I will get.

Also wanted to add that when I say it is hotter, I am thinking 2-3 degrees difference, maybe. Also, I think it would be possible to add another vent. The ducts are in a crawl space, so very accessible. Is it better to just increase the duct size or to add another run?

frangione

the Man J is a computer generated software package used for properly sizing residential HVAC. it will clearly be identified as such. the true professionals will use the Man J because it is a measure of protection for both the dealer and the homeowner against sizing errors.

as said many times, dealers who refuse to do it fall into the following categories.

1.don't know how, ie ignorant
2.too damn lazy-yes it can take an hour or two to perform
3.don't give a xxxx about their customer.

a couple of ideas.

1.where is thermostat located? preferably it should be on inside hallway near the return away from any windows, heat source.

2.the temp differential of this problematic room that is the room furthest from the outside pkg unit is not unusual. I would continue with your damper changes to see if this helps. also, I would run the var speed fan/blower in the continuous "on" position to see if this smooths out temp differences throughout home.

3.what size is this room? what is ceiling height?

3.how is this room insulated? can any inexpensive improvements be made?

4.how many supply vent/registers serve this room?

5.verify the size of the supply duct(s) serving each vent/register. this is important.

6.I would ask dealers to measure CFMs entering this room. before install and after install.

7.I assume that room is hotter in summer,cooler in winter. correct?

I probably would not make any ductwork changes without knowing more information particularly the airflow before and after install.

anyway, hope your install goes well and uneventful today.

TD
Good LucK!

The thermostat is located in the hallway, with no vents near it. The return is below the thermostat.

The room is 26.5 ft x 12 ft. The cathedral celing runs through 19.5x12 ft of the room. It starts at 8 ft and goes up at a 45 degree angle to about 15 feet. There are only 2 vents in this room. The room is obviously hotter in the summer. I can't say for the winter for sure as I haven't taken a real measurement and I am always cold. I think the skylights are a big problem. We don't have any kind of shades or anything in them. That might help for the summer heat.

I assume the insulation is typical for a house bult 15 years ago. I don't know if that can be improved without getting someone out to take measurements of any heat loss/gain.

The installers are here and say that they don't have equipment for measuring air flow with them. That is a bit bothersome.

frangione

at the very least, verify the size of the supply runs to this room, that you have adequate insulation R8 recommended , and properly connected and insulated at the main trunkline and at the boot to the supply registers(no leaks). if you don't have R8 insulation on these runs,I would strip off the old and add R8-something you could do yourself. Insulation update doesn't have to be done today but both you and installers should check these runs to this room very thoroughly.

TD

When you are talking about size of the supply runs, you mean the diameter of the duct, right?

I don't go into the crawl space, I leave that to my husband. But I have peeked in there before and I don't think the runs are insulated. I don't know about the trunkline and boot. Is the trunkline and boot normally insulated (even for a 1993 house)? I can get my husband to add some insulation.

"When you are talking about size of the supply runs, you mean the diameter of the duct, right?"

yes, without any insulation on top.

"I don't know about the trunkline and boot. Is the trunkline and boot normally insulated (even for a 1993 house)?"

all ductwork including main trunkline and return plus supply runs should be insulated with at least R6 insulation.

as stated in earlier post, these supply runs to the room in question should be thoroughly checked as to leaks at the connections plus good insulation.

and I don't care for crawlspaces either.

Good Luck!

Okay, so the install is done and everything is working. We spent a little time adjusting the dampers. They make a big difference in the air that comes out of the vents. It is really coming out of our problem room. Whether that matters or not, we will see.

The supply run is 9". The runs that go from the box to the individual vents are 6". All the ducts are insulated with R-4.2, so that can be improved at some point.

I got the thermostat all set up and changed the balance point to 35 degrees and will go from there.

frangione

Congrats on install. Replacing HVAC can be very stressful.

I am happy to hear that airflow to problem room appears to be much improved. if you are so inclined, you might want to take some temperature readings from the rooms this system serves. they should be very close within 1-2 degrees. and please keep those filters changed.

If your home is comfortable at 35 degrees outside temp when in HP mode, then I would reduce changeover point down to 32 degrees. keep in mind the main idea of dual fuel is to leverage reasonable electric rates vs more expensive nat gas rates but still maintaining inside comfort.

new system has the var speed blower and you might consider placing fan in "on" position and run continuously. cost is really inconsequential since the var speed is DC motor.

Good Luck!
TD

I was reading this posting with much interest - I have an 11 year old home, cracked heat exchanger and an a basic Trane unit. I have been recommended a Carrier 48XZ Hybred which appears to be variable speed motor with gas furnace/electric heat pump - with humidity control...

My issue is finding a contractor since we are new to the area, and the home warranty company is recommending Carrier as a replacement for the Trane.

The unit above is a major investment over the cost of the basic unit, but reading your post seems to indicate that it is a good idea for living in NC?

I can't help you much with regard to brands. TD might have more to say about it. I think Carrier is a fine brand, but Trane is a little bit better. One of the installers that gave me a quote said that he has had lots of issues with Carrier units in recent times and felt that they were going down in quality a little bit. How true that really is, I don't know. You can always get the extended labor warranty to protect yourself.

I think a lot of people recommend dual fuel, regardless of climate, just because of the cost savings when comparing gas/electric. I don't expect to get a lot of use out of the gas being here, but it will kick on from time to time. For me, it came down to whether I thought I would be in this house long enough to realize the savings because of the higher up front cost (about $600 for me).

I am assuming you are in NC? If you are in the Raleigh area, e-mail me and I can give you specifics on companies I got quotes from.