Building a new home..2 units OR 1 unit with zoning? Newbie needs help..

[lithnights]

I've done 2 systems in homes keeping both in the basement and I've had builders but the utility room on the second floor. With todays taller ceilings the ductwork can stay out of the attic.

Yes I've seen this before as an option. But with the current design, there isn't really a place to put such a utility room on the 2nd floor. The 2nd floor is huge, so it's not like room couldn't be found, but with the design as is, there's not a dedicated space. It's something I'll have to discuss with the builder.

[NY2GA01]

Regarding the 2nd/3rd opinions, how would one do that if the builder is in charge of the HVAC and uses a certain HVAC sub? Does one ask them to go out and get a 2nd opinion, or does the homeowner find that 2nd opinion?

I would never build a house with 2x4 outside walls, 2x6 is the only way to go.


This is your house, not the builders, so that would be your guys at your cost if any, not his. Nothing says you have to use the builders contractors.

I am pretty certain the builder has shopped out who is going to do his work for the lowest rate, and that usually does not mean quality work.

[arc8]

I would never build a house with 2x4 outside walls, 2x6 is the only way to go.


This is your house, not the builders, so that would be your guys at your cost if any, not his. Nothing says you have to use the builders contractors.

I am pretty certain the builder has shopped out who is going to do his work for the lowest rate, and that usually does not mean quality work.

I concur..

[arc8]

Normally I would go with one system except he's thinking of using heat pump(s). One (1) five ton (approx. 45,000 Btus) HP won't do him much good. He'll be on back up (electric) heat all the time.

I missed something!
I did not see his Heat Load anywhere, nor did I see his utilities rate..

If his electric rate is high and his Heat loss is higher than 45,000, then I can agree, till then, I can't agree just yet...

[George2]

I missed something!
I did not see his Heat Load anywhere, nor did I see his utilities rate..

If his electric rate is high and his Heat loss is higher than 45,000, then I can agree, till then, I can't agree just yet...

You gotta chill....LOL. Correction on my part......a 5 ton HP will put out approx. 55,000 Btus. I'm just saying (hypothetically), for 3,300 sq. ft. with a full basement, he'll need at least that much heat. Throw in zoning and he'll have a lot of airflow with only one zone calling.

I hope he let's us know the heat loss/heat gain of the home. It sounds like it'll be a tight home with good insulation.

[tipsrfine]

i.e. PECO $0.096 / kW-Hr after 1Apr13

http://www.papowerswitch.com/shop-fo...eco-energy/rh/

Builder and mechanical contractor/HVAC should pay any electric cost for heating > $600 / year for 10 years
( pro-rated to $0.096 / kW and 5,000 Heating Degree Days [ HDD])

If there are only 4,000 HDD in a Winter season, any annual electric heat cost > $480 to be paid by builder/ HVAC installer.
........................6,000 HDD .................................................. ..................> $720 ........."....... " .......... "...............

Is the part in red just your opinion, or is it part of some rule or program?

[lithnights]

Just to give a bit more info, see below. I pasted this from a different thread I had done earlier about heat pump vs. propane furnace. But it will probably help here..

-Philadelphia, PA area. Number of days that AVERAGE 32 degrees or below..35. Number of days that the LOW temp drops to 32 degrees or below..100 (basically Dec through mid March). On average, the lowest temp of the year is 23 degrees.
-House will be well insulated. 2x6 walls. R19 in walls, R50 or so in attic. I have stressed the importance of insulation to the builder. Assuming I go forward with the spray foam (builder estimated about $6K extra), the house should be as tight as I can make it.
-Gas is not available unless I want to spend $60,000 to extend the line
-Propane about $2.80ish a gallon
-My current electric with PECO is $.165 a Kwh
-House is about 3200 sq ft., about 1600 on 1st floor and 1600 on 2nd floor. Basement is just as big, and will likely be finished in the future.
-I plan to have an efficient woodburning fireplace (RSF brand..heat capacity 1500-3000 sq ft) in the family room, which should be able to heat much of my home..at least the first floor from what I am told by the fireplace experts. I understand I'll be loading this fireplace several times a day.
-I prefer propane for the range and hot water heater, and I plan to install a whole house generator in the future, so I want to have an underground propane tank (500 gallon or so?).
-My contractor is pushing a 85% efficient propane furnace. I want to do an electric heat pump with a propane backup.
-I plan to be in the home 20+ years.

[lithnights]

I would never build a house with 2x4 outside walls, 2x6 is the only way to go.


This is your house, not the builders, so that would be your guys at your cost if any, not his. Nothing says you have to use the builders contractors.

I am pretty certain the builder has shopped out who is going to do his work for the lowest rate, and that usually does not mean quality work.

Noted. I've never built a home before so I simply am not sure of the options I have as far as subs. i.e. if I wanted a different electrician to do the work, I didn't think I could tell the builder to use ABC electric instead of his sub. I assumed the same goes for HVAC but I guess not.

[lithnights]

You gotta chill....LOL. Correction on my part......a 5 ton HP will put out approx. 55,000 Btus. I'm just saying (hypothetically), for 3,300 sq. ft. with a full basement, he'll need at least that much heat. Throw in zoning and he'll have a lot of airflow with only one zone calling.

I hope he let's us know the heat loss/heat gain of the home. It sounds like it'll be a tight home with good insulation.

So how do I know/get the heat loss/heat gain of the home? Is that something I can find out now, or do I have to wait on the manual J to tell me that?

[dan sw fl]

I did read the reply in post #6 but don't see where it mentioned that 3 tons could be too much. Am I missing something?
I'll be sure to look into spray foam for the roof underside.

O Ceiling R-45 ... spray foam on underside of roof ... ALL ducts in conditioned space
O Walls R-16
O Windows U < 0.3*
O Air Change per Hour (A.C.H.) < 0.25*
_ _ If one Strictly Adheres to the 4 mentioned energy conservation measures

" Builder needs to Guarantee performance < 16,000 BTU/Hr @ 10'F per floor."

//.. < 32,000 BTU/Hr total < 3 tons.

[George2]

So how do I know/get the heat loss/heat gain of the home? Is that something I can find out now, or do I have to wait on the manual J to tell me that?

You can do it yourself off your house plans. Or have someone do it for you. I have seen services on the internet that will do it for less than $100.

[arc8]

lithnights,

Your average HVAC won't do it or don't know how to.. If I were building MY house, I would find and demand my choosing of companies unless this builder is a Topnotch company, speaking of which, I haven't found any in my area that I could rely on 100%...

Best of Luck..

[lithnights]

Just a followup, now that I'm deep into the house build. I am in a bit of a bind. After asking for the Manual J analysis for weeks, the builder never sent anything. Then I met with the HVAC guy on site one week ago, and was told for the first time that they are doing a single unit 5 ton 95% 13 SEER heatpump (with propane backup). ONE UNIT? Not 2 units, not even zoning.

Before we signed the contract, the builder said they almost always do 2 units for anything over 3,000 sf. Now suddenly my 3,250 doesn't need 2 units? The contract simply stated.. "Heating: Electrical heatpump with propane backup" Yes, very generic, and I should have called for more detail, but I didn't know. Contractually I'm not sure how this is handled but that's a question for a real estate attorney I guess.

How can a 3250 sf two story house be comfortable with just one unit? Builder and HVAC guy assured me it would be fine of course, but I have my doubts. Keep in mind, this builder has been working with the HVAC company for decades, so neither wants to step on the other's toes. My guess is the builder basically told HVAC they're doing 1 unit so make it work. So it seems like the fox guarding the henhouse. Know what I mean?

Anyway, I'm in SE PA area, 2x6 walls, Andersen 200 windows, house faces south, almost no tree coverage. I asked for some analysis and they simply provided me with what you see attached. What does this truly tell me? I've heard that the Manual J doesn't truly specify whether 1 or 2 units is needed? Is this true? If it doesn't, what tells us that?

I had another HVAC guy come through, and he said I'd be "OK" with one unit, he would have done 2 units (bigger heat pump in basement, smaller heatpump in attic). So now I want to get a 3rd opinion, or is there a way that I can run it myself? I believe there are programs out there. Any suggestions?

The builder said I could pay $3600 for a 2 zoned setup, or pay $6100 for a 2 unit setup. I never budgeted for that, so now I'm in a major bind.

Bottomline, what SHOULD this home have to have acceptable heating/cooling? I don't want a 5 degree differential between floors for the next 20 years.

Help!?

I posted this as a separate thread recently, but just wanted to update this thread as well since everyone had been so helpful when I originally started thinking of 1 vs 2 vs zoned..

http://hvac-talk.com/vbb/showthread....50-sq-ft-house