New House - Central Air

[Alan L.]

Alan,

I just installed 2 heatpumps in my house and barn. Ok, I installed the barn, a HVAC contractor installed the house. They did re-use some of the existing ducting, but here is what they did. 5 Ton, Carrier Infinity system, 17 Seer, 2 zones and associated zone controllers and dampers, Honeywell electronic air filter, all runs under the house hard pipe, 2 story, 3800 sqft house with 2 thermostats, etc....$14000.

I think for your size house, you can probably do better, my system is pretty much top of the line, (I did get a bid on a Trane - 8 zones - ~$22000 - so I passed). I chose a heat pump for 2 reasons, electric rates are somewhat regulated (at least the increases are much smaller than gas or god forbid - oil) and the other is that I wanted to replace the oil furnace I had and remove the tank. I am glad I went the electric route, to have gas installed to my property was close to $30000 (I didn't really want to spend that).

The actually install of the system took 2 guys about 8 days (working) and they did a nice job. The finish work took almost longer as they were having some problems with one of the zone controllers, but it is sure nice sending all the cold air upstairs at night and none downstairs, and vise versa during the day.

Derek

How do you think the multiple zones works energy wise vs separate units? Obviously one unit with 2 zones is less money than 2 separate units.

Also, does anyone have a loft? My A/C guy has one (and we will) and says the ac won't stay up there because it goes downstairs. Says maybe not a problem with us since the upstairs will only need serious cooling when we have visitors or we are cleaning up there. The master is downstairs and our kids are grown.

 

[hilld]

How do you think the multiple zones works energy wise vs separate units? Obviously one unit with 2 zones is less money than 2 separate units.

Also, does anyone have a loft? My A/C guy has one (and we will) and says the ac won't stay up there because it goes downstairs. Says maybe not a problem with us since the upstairs will only need serious cooling when we have visitors or we are cleaning up there. The master is downstairs and our kids are grown.

I think the multiple zone's work great and are more cost efficient. The other advantage is that you only have one outdoor unit and 1 indoor unit, but you do have to run the ducting to both floors rather than keeping them seperate. In addition, you only need 1 electronic air filter if that is something you are considering. Make sure you get a variable speed system that can stay running all day (just the fan) and keep the air moving and filtered.

My last house was a 3 story with 3 seperate systems and it worked just fine. The advantage I find with the zone system is that I can control the different floors from one thermostat, rather than running upstairs to turn on the system. Also one place to program and turn on and off.

The advantage to a multiple unit system is that you don't have to run duct work up a wall to another floor and take up valuable space, however, you have to run multiple electrical runs, 1 to each unit as well as copper line sets and drains from the evaps to the compressors. If a system were to fail, you are not out in the entire house - could come in handy at times.

Given the fact I have done it both ways, I "think" I like the 1 unit multiple zone idea, but I haven't had a failure of the unit yet, I did have one of the units fail in my previous house (fan stopped working - took 4 days to get replaced).

Sorry for the confusing answer.

Derek

 

[MF1455v]

Alan, we have a 4ton and a 2ton, both 14 seer on our house. Don't remember the name of the units but the supplier can get about 8 different brand lables for the same unit. Both have voltage monitor installed to protect the compressor from our country voltage sags. We also have return air in every room. The units are installed in the atic with unistrut and chain, not duct strap. The entire cost was $8,000 but that was 6 years ago. My AC guy did HVAC where I work. I could have gotten the job done cheeper but not better. On our next house I will just tell him when to start and give me the bill. I will send you a PM with his number. Give him a call. Maybe he can give you another option.

James

 

[InlineDieselFan]

Alan,

Can you describe some of what you are putting in your house?

Glue lam beams with 20 foot ceilings sound real nice, along with all of the brick work, and Anderson windows.

I know prices vary, and I live in a high expense area, but some prices seem low to me.

Appliances, for $3,500? I was around $10,000.

Flooring is $5.00 sq foot, I would then assume not wood or tile, perhaps soem tile in the master bath? Good Carpet and pad run $4.00 and up per sq. foot.

Electrical per square foot? I would be careful on this, how many can lights, does this include lighting fixtures, in the bathrooms dining room etc? How many plug ins will this give you? How big will the breaker panel be, 200 or 320 amp? Go 320 or bigger if you can especially since you have those two AC units. Also Generator ready? It is fairly cheap to do now, you can get the generator later.

You mentioned the extra money for the doors, be sure to hard shop for those as they vary hugely in price and quality.

steve

 

[VA_Joe]

Think of it as a system - the better you insulate and the better your radiant barrier (i.e. metal roof) the smaller the AC unit you will need (and therefore a lower savings between the 13 and 19 SEER). That foam insulation has amazing R values and moisture blocking properties (just remember to put in a recovery system to bring in fresh air). Have your HVAC guy plug in the different R values into the computer program he uses and calculate the difference in unit size (and system cost).

Another thing you can do to keep HVAC/electrical costs down is to use compact flourescents vice incandescent light bulbs. Incandescents are 99% heat/1%light. CF's will do the same job with much less heat output. I have done this in my house and am benefiting from noticeable drop in electrical usage.

BTW - you probably already thought of this - don't skimp on placement of electrical outlets (you can never have to many).

Hope this helps.

Joe

 

[moss2940]

You might look around this site.
HVAC-Talk: Heating, Air & Refrigeration Discussion - Residential HVAC

 

[Sigarms]

Not sure how they run ductwork in Texas, but I'm assuming the price you got for the HVAC system includes ductwork.

Remember, the ductwork is either going to be fiberglass or metal. If it's metal, it has to either be lined or wrapped.

From last year, sheet metal prices went "through the roof" (no pun intended).

Copper (for your linesets) have litterally doubled in price from the beginning of the year.

Zoning would be an option. I was told by someone here on this board from Texas that load calculations were a waste of time for homes in Texas, so perhaps a zoning system would be no good in Texas, I don't know.

 

[Alan L.]

The on real bid ($13,500) I have so far is for 3 two-ton Rheem heat pump separate systems - 13 SEER I think, maybe 14 SEER. This includes the ductwork and everything. With some exception everyone uses flex duct around here. I am told it is much quieter in operation, although the metal ducts with insulaton are probably somewhat more efficient and durable, but they cost alot more.

My neighbor who is also working on a bid does all the J Load calculations, whatever you call them, and then increases that by a half or full ton. He says the guys that design the compuations just don't understand how much cooling it takes here in Texas when both the temp or humidity or both may be VERY high for a long period of time. We have had 41 days over 100 degrees this summer, and many nights it never gets below 80. Putting in a system by the book will allow you to get your house to 85 when its 105 outside and thats just flat unacceptable.

So, we either have to live with the drawbacks of having too much tonnage in lesser cooling periods causing some humidity problems, OR we can pay double for one of those high priced dual stage systems, like the Trane 19i, or we can just be hot and uncomfortable about 60 or 70 days a year when it is REAL hot.

I experience first hand the problem of having too much a/c - my building has a 3-ton 10 SEER unit in 880 square feet. In the early summer when it is humid we have to cool it down pretty good to get it comfortable, but its nice when its 105 to be able to get it to a comfortable 70 degrees. I did this living quarters all wrong - there is fiberglass insulation everywhere, but I didn't seal the metal skin to the windows properly so the outside air blows right through the batt insulation making it useless.

This is why I really want the foam. The R value is really not that much more than batts when you use the low density foam, but it is the R factor plus air sealing capability that makes it effective. Plus, it achieves the stated R factor in the real world, whereas fiberglass does not. However this is all mostly anectdotal evidence. You can find very little in the way of actual real world testing of foam insulation, sealed attics versus conventional insulation. It is proven that foam/sealed attic gives you a cooler attic, but it is not proven that this results in a lower cooling load since there is no insulation between your 78 degree house and 83 degree attic. Makes it real hard to spend all that money when you don't have much to base the decision on.

I am rambling on, but I am starting to lean toward the metal roof, foam in the walls, and conventional insulation in the attic (although I do have to foam the cathedral ceiling). Plus either 3 14 SEER units or 2 units plus a minisplit for auxiliary cooling in our master bedroom. I'm sure I'll change my mind before its over.

As for the electrical, my friend has seen my plans and all the can lights are on there as are all the plugs and he thinks the electrical will be fine.

As for appliances, we are going with standard consumer grade appliances something like this:

Double Oven $1600
Jenn Air Cooktop $650
Dishwasher $600
Microwave/vent $400

The fridges & freezer are not part of the allowance - we'll furnish that separately.

As for flooring, the allowance might be a little light. We are doing about 750 sq feet of solid oak floors which is $10 a square feet installed over a plywood underlayment. That only leaves about $2.30 per foot for the rest of the house. Thats about $21 a yard for carpet which might be a little short of what we will spend, but frankly, $21 is about all I have ever spent for carpet and have been happy with it. It usually lasts long enough we are tired of it and want new carpet anyway. The carpet we have in this building we paid $16 a yard for, and I like it fine. We replaced the original carpet after 4 years as we were sick of it anyway.

I was not aware of the ability to choose between 200 amp and 320 amp service. I will bring this up. Is that the total of the breakers that will go in the box?

As for the prices, my impression is that things are more expensive in the northern and eastern states because of more unions and more building regulations, but with this I think comes special workmanship.

Please keep the good information coming. This is invaluable information for someone building a house. I fear that after all of this, we will go into debt and spend alot of money and then not be happy because we settled for something other than what we had dreamed our house would be. Or, we spent more than we can comfortably pay for. This is no mansion of course, but we plan for it to be our last house.

 

[CurlyDave]

Jenn Air Cooktop $650

I would scratch the Jenn Air cooktop if it is one of the downdraft vent types. This is the worst idea in venting a cooking surface I have ever seen.

Hot air rises & trying to force it down means too much air flow.

Go for a real hood over a cooktop.

 

[Redneck_Randy]

I'm late getting in on this thread and admit I didn't read all of the replies. When fitting a new home for A/C size the rule of thumb is 1 ton per 600 sq feet. If you go under that rating the unit will not cycle properly.