Newbie building home..PLEASE help with setting up ideal heating and cooling system?
Just found this site and love it so far! I'm building a home and I want to make sure I make the right decisions on the heating/cooling setup. I'm a newbie but I've spent countless hours online researching things, then found this site and figured this would be a great resource. Here is my information..I figure I'd give you more than less to better help answer my questions.
-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. Short of spray foam, 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 3140 sq ft., about 1550 on 1st floor and 1550 on 2nd floor. See attached pictures. 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.
1. Do you agree that the heat pump with propane back up is preferable to the propane furnace?
2. I'd like to utilize the wood fireplace to push heat to the rest of the house. One suggestion is to send it to the basement and duct it directly into the main heating system trunk. This would push the heat throughout the house. Another suggestion is to send it to the basement, duct it across the house to the opposite corner (living room) and have a vent there. This would keep that area from becoming a cold zone when the fireplace is running and keeping the family room/kitchen area toasty. Thoughts on this?
3. Does it sound like I'd need a 2 unit/zoned heating system, one for each floor? The builder says I'm right on the edge of needing 2 units but he'd have to have the York guys run the numbers to determine, I assume using a Manual J. Also, would they take the fireplace into consideration at all for this calculation, or not b/c it still needs to be big enough for cooling? I assume the latter.
4. I've researched like crazy and often read that heat pumps aren't too effective once the temp hits, depending on who you talk to, 35 or 30 or 25 degrees or whatever. But then I hear that something like a 2 stage Greenspeed unit WOULD work OK as temperatures plummet into the teens. So what's the deal with the capability of heat pumps in cold weather, and in my area (see the stats above) and my wood burning plan, is it a concern?
5. Does a heat pump with propane backup, mean that I basically have a heat pump AND a (backup) furnace, or is it one unit? Trying to project the price of it compared to the builder's proposed 85% furnace.
6. If the house turns out to be 2 zones/units, does that mean I need 2 heat pumps?
7. If I get a heat pump with propane backup, should the furnace part be ultra efficient (95%) or is it not worth spending the extra money since it hopefully won't be running that much?
If this is too many questions at once, please let me know for the future so I know to tone it down a bit.
Thanks so much in advance!
I'll try to answer your questions.
A heat pump (HP) is like an air conditioner (AC). It is a separate unit vs. the furnace or air handler (which moves the air and will be the back-up heat).
Most HPs, to be most efficient, need to shut down around 30 degrees. Then the back-up heat (gas, propane or electric) turns on. The "variable speed" (not 2-stage) Carrier Greenspeed is the most efficient HP and doesn't need to shut down early.
Some utility companies will give a big (rate) break to a home that is all electric. You then would need electric air handlers (with staged electric heating). I believe you can still have the LP hot water heater, stove and dryer to receive the special rate. Something to look into and consider since you will be heating mostly with wood.
I would recommend two systems (that'll be 4 major pieces, 2 inside and 2 outside). Both furnaces could be located in the basement or a utility room for the second floor system is even better. Both furnaces should be designed to have zoning. Note: Carrier also makes a killer (Infinity) zone system.
Regarding the furnace efficiency needed. I like the 90+% AFUE because they use (you need to ask) outdoor combustion air. This should be an obvious reason in itself. But it also keeps the units quieter than the 80% furnaces. Of course, if you go with electric AHs none of the venting or combustion air becomes an issue.
The major problem you'll face is finding a good HVAC contractor to properly size and install the equipment. Make sure to go with "variable-speed" blowers and good air cleaners. Carrier offers the best options there as well. Some on this site say they don't like Carrier. However, ALL the technology we now enjoy, came from Carrier's R&D.
Yes the fireplaces are accounted for in a manual J. They add a little loss unless they are air tight.
2 units, or zone it. Other wise you probably won't get even temps from one floor to the other.
With dual fuel, you'll an outdoor unit, and a furnace with a coil attached to it. You would be better off with a 95% furnace then a 85%.
At the propane rate you posted, 85% furnace is 3.57 for 100,000 BTUs of delivered heat, 95% is 3.20 for that same 100,000 BTUs of delivered heat.
Are concerned about about indoor air quality? Mainly fresh air ventilation and humidity control? If not disregard.
Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
Use +Merv 10 air filter. -Don't forget the "Golden Rule"
Got it, variable speed, not 2 stage. I have read that the Greenspeed is the most efficient HP, just wondering if it's something I should push for in my situation (with my weather), as opposed to just a typical heat pump.
I'll check with the utility on the electric break rate.
With the 2 systems, I don't have a utility closet space upstairs (there's likely enough room but we'd have to redesign the home) so they'd likely put both in the basement.
So back to my other confusion (questions 5 and 6), does that mean I'd have, on the inside, 2 heat pumps along with 2 furnace/air handlers?
I agree about the challenge of finding the proper HVAC guys who know what they're doing. My fear is with the builder pushing propane, that is what he and his subs are used to. I want to make sure we use someone who knows what they're doing with a heat pump install. I'll mention the variable speed blowers and good air cleaners.. but what exactly do these do to benefit the system?
Originally Posted by George2
If the HVAC subs your builder uses aren't carrier dealers. You don't want someone installing a Greenspeeed.
Yes...you'll have two furnaces/fan coils inside and two HPs outside. The Carrier dealer will have a program that will show you exactly (in a matter of seconds) the operating costs of all the systems that are of interest.
Did I also mention that Carrier has the best zoning. Note: Some have copied it (the modulating zoning) as well and try to take the credit. Just a FYI.
Regarding the use of propane, check with your utility company to see if they'll give you a electric rate break.
Carrier wasn't the first to come out with a Mod furnace. Rheem/Ruud was, and it was about 15 years before carrier. carrier wasn't the first to come out with a variable AC, Trane was, about 20 years ago. Nordyne came out with a modulating heat pump 4 or 5 years ago, so carrier didn't invent that technology either. Not even sure Carrier was first to come out with a 2 stage A/C. So Carrier's R&D didn't come out with all the technology we enjoy in HVAC today.
Originally Posted by George2
Okay, maybe I exaggerated just a wee bit............ They do offer a few good ideas. It's not a bad line is my main point.
OK, got it. So the heat pump sits outside much like my current compressor does for my AC unit? I guess that's where I was confused. I thought it was on the inside. I told you I was a newbie.
So with that said, if my builder currently includes a 85% propane furnace (doesn't state single or dual zone/unit) in the contract, and I say I want a dual zone heat pump with propane backup, that essentially means he has to put in 2 more heat pumps and 1 more furnace than he had planned, right? How much in material and labor am I looking at for this? Just trying to budget as best I can and not be shocked by the numbers.
I plan to check with my electric supplier for any breaks.
Originally Posted by George2
No its not a bad line. You pay for all the advertising they do, and that large R&D department they have.
Originally Posted by George2
And their mod zoning system is top of the line.
Noted. My fear is that unless the Greenspeed is stated in the contract, and he usually works with York guys (York unit is stated in the contract), the builder may give pushback on me wanting to use the GreenSpeed unit. Or may charge an arm and a leg since I'm not using his normal subs.
I guess that's why I'm curious, for MY SITUATION, would I definitely be better off with the Greenspeed or would I be OK with a standard heat pump?
Originally Posted by beenthere
Last edited by mbarson; 01-06-2013 at 06:06 PM.
Reason: Forgot the rules! Deleted post.