Heat pump + furnace rec's?

Greg_R

New Member
Jan 25, 2012
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Hi all,
We are considering replacing our existing gas furnace with a new gas furnace, air cleaner, humidifier & external heat pump (for A/C). I'm considering Carrier, Trane, Lennox, and York. Are there any other recommended brands or things to avoid?
 

amirm

Banned
Apr 2, 2010
15,813
37
0
Seattle, WA
You will have one heck of a time researching this field. There is next to no reviews. And claims are made that components are made by a few companies that others package and then resell.

We bought a York furnace when they had rebates for high-efficiency units. It is gas and has a unique feature which is variable speed. It works incredibly well. The unit never cycles on and off but rather, learns over time how much heat your house needs and runs at that level. If that is 28% heat, that is what it provides. As a result, the temperatures in the house are incredibly stable and comfortable.

On heat pump, we have a Carrier Infinity. Two of them as a matter of fact. The unit works fine but compressors are noisy even though this is the best they have with dual cycles and such. With a gas furnace, it is just the air handler that makes noise. With heat pump, the compressor does that too outside. So be sure to place it some place away from bedrooms and such. We had no choice since our vacation house is electric only and no gas feed. For primary house where we do have gas, I would not get a heat pump for that reason. That said, there is something to be said about safety of a no-flame unit.

Our last furnace was a Trane. It lasted 5-6 years before its blower controller went bad. It was going to be a $1,500 repair on a $4,500 unit. Prior to that it had other parts go bad. So bit the bullet and replaced with York, making sure to get a long term warranty on the parts as these controllers do die. So be sure to look for that. I think ours has a 10 year warranty on parts.
 

Greg_R

New Member
Jan 25, 2012
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Amir, a friend of mine just got a heat pump + gas furnace combo and he claims that the furnace rarely needs to kick on because the heat pump can handle daytime heating in the PacNW. I worry about Trane... they advertise a lot so I wonder if that's where their budget goes (instead of into the equipment).
 

amirm

Banned
Apr 2, 2010
15,813
37
0
Seattle, WA
Ah yes. A heat pump gets available heat from the outdoor. That process works most efficiently when the temp differential is small. By the time you get to 30 or so degree difference between inside and out, the heat pump becomes pretty inefficient and past that, it simply cannot keep up with the demand. The solution in the unit we have is a simple electric element. The one your friend has is gas. As with his, our electric element doesn't come on most of the year since our average temps are in the 40s and with indoor in the high 60s, you are still within the range of the heat pump working domain.

On Trane, yes, i crack up when they say "nothing can stop a Trane." Ours sure stopped by itself often like an economy line. :D
 

Greg_R

New Member
Jan 25, 2012
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I thought I'd post an update on my research and purchase for anyone else looking @ heatpumps & furnaces.

The first thing a home owner should do is a Manual-J calculation to determine the heat loss/gain in a home. While there are free programs available, I found this one to be accurate and easy to use (i.e. worth $50): http://www.hvaccomputer.com/

The installation is as critical as the brand of equipment you select. I'm a big fan of picking Angie's List A-rated businesses and for this job I waned the installers to all be NATE certified. Also, companies with their own metal fabrication shop will be able to do a much better job on your plenum and duct work if that is a part of your install. Pressure testing your duct work is always a good idea to find any trouble spots. Duct cleaning is not always necessary and can be done post-install if required.

The next question is which heating method is going to be the cheapest to run in a particular locale. One important point to note is that you'll NEVER pay for a system on the energy savings. You -MIGHT- pay for the difference between a high efficiency and low efficiency option. In other words, don't bother installing a geothermal system if your only reason is to "save money". In my area of Oregon, we have cheap electricity and somewhat cheap natural gas. Comparing the cost of running gas versus a heat pump (given the annual heating load of the home) it was very clear that a heat pump was the best option.

Carrier currently sells the Infinity Greenspeed which is the most efficient non-geothermal heat pump by a significant margin (and it's the most expensive). Again, A/C performance was not a huge issue for my locale so I didn't heavily factor it into the analysis but the SEER rating is also very good on the unit. Of particular note is that it can maintain it's BTU output down into the freezing temperatures while all other HP designs tail off. I determined how much I'd use my gas furnace and it ended up being ~$70 worth of gas a year if I got the Greenspeed HP. Buying a high AFUE furnace in this case makes no sense ($10/yr savings is not going to pay for the $1.5k price difference). I also considered electrical heat strips (they sit in the air handler) but I like the idea of a flexible heating solution if gas prices suddenly become very cheap. This brings me to another positive about Carrier: they sell a high end air handler with an 80 AFUE furnace (80 is not efficient). All the other major brands force you to buy their high end furnaces if you want a fully communicating system. The fully communicating / learning systems is what gets you most of that efficiency. I was able to buy the 80 AFUE option which saved me a bunch of money on the install and equipment costs that I would never make back given my gas usage. Oregon is banning the sale of 80 AFUE furnaces next year so I just managed to squeeze in before the deadline :).

With any quoted system, request the AHRI number and look it up on their database for the "real" SEER and HSPF numbers (the entire system, not just the heat pump).

As for air cleaners, I'm not a fan of the fully electronic options because I forget to vacuum them out every few weeks (reducing effectiveness). There is also the issue of ozone creation with some of these options. Carrier offers a MERV 15 option that uses filter media + electronics with no ozone. A better option would be the IQair MERV16 unit but some dealers don't want to work with parts they don't carry. With any filter, it's critical to ensure that the filter can maintain the required CFM for the system. Also, having a variable speed DC fan in the air handler allow you to run the fan on "low" forever to constantly filter the house air. The fan on 'low' burns about a 60W lightbulb's worth of electricity.

In terms of downside, Carrier does not have an internet-ready thermostat (Trane does). They are supposed to come out with something late this year but they've been promising that for 2 years now. You need to use the Infinity thermostat to get the benefits from the communicating technology (high efficiency) so aftermarket solutions are a non-starter. The thermostat keeps track of the pressure and CFM in your ducts and will alert you when there is a drop (i.e. time to clean or replace the filter).

For the data geeks -->
You will have one heck of a time researching this field.
You were not kidding. That Home Site had some good information to get me started. My next step was to perform my own heat loss/gain calcs and plug everything into a spreadsheet. I took the high and low temp of my location for every day since 1950 and calculated how many BTU of heating and cooling would be needed each day (Heat loss/gain = (home constant) * dT where dT=temperature difference between the inside and outside). Using that information, I could determine how much each option would cost me based on my utility rates (careful with the rate tiers!). For each system, I found the AHRI ratings which allowed me to produce a crude output curve for each system. Finally, some systems are variable (energy use is somewhat linear) while others are 2-stage or on/off (stair step plot for energy usage). Merging all of that data together allowed me to determine which system would be the lowest cost option after X years. For our home, the Greenspeed HP became the cheapest option after 3.5 average years of operation. I did factor in consumables (filters, etc.) but not repair costs. Carrier has a 10yr warranty if you register the equipment through an authorized dealer.

Anyway, I hope that this helps the next person who comes along!
 

Gregadd

WBF Founding Member
Apr 20, 2010
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Metro DC
Don't forget to check for tax breaks and rebates.
 

Greg_R

New Member
Jan 25, 2012
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Stick with Lennox. My guy sells trane and carrier too and doesn't recommend them. The high efficiency Elite series with variable speed blower motors are best. I just replaced my 20 year old furnace back in June. 90,000 btu's 96% efficient.
http://www.lennox.com/products/furnaces/EL296V/

About $4,600 installed.

Hmm... my Trane guy carries Lennox and didn't recommend them :). I think it has more to do with dealer kickbacks & promos than equipment longevity. At any rate, go with a dealer with excellent support of their system/product... that's the important thing.
 

Greg_R

New Member
Jan 25, 2012
95
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0
Stick with Lennox. My guy sells trane and carrier too and doesn't recommend them. The high efficiency Elite series with variable speed blower motors are best. I just replaced my 20 year old furnace back in June. 90,000 btu's 96% efficient.
http://www.lennox.com/products/furnaces/EL296V/

About $4,600 installed.

Paying more for an efficient furnace was a complete waste of money for me given my HP selection... see above. Obviously for different locales the math is completely different (type of home, how cold does it get, cost of gas, etc., etc.).
 

Garth

Member Sponsor
Feb 23, 2014
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I have had the same heat pump since I had the house built in 1988 with under floor heating. I think it is the best way to heat a house
 

rockitman

Member Sponsor
Sep 20, 2011
7,097
412
1,210
Northern NY
Paying more for an efficient furnace was a complete waste of money for me given my HP selection... see above. Obviously for different locales the math is completely different (type of home, how cold does it get, cost of gas, etc., etc.).

The best furnaces have two stage variable speed fan motor. They comtinue to periodically circulate the air w/o the furnace kicking on and maintaining a better, more even heat/humidity environment. To me, that is more important than pure efficiency. I just replaced my AC unit with their top of the line, perfectly synergistic with the furnace. Once again, variable speed fan motor. More even cooling, better humidity control and it's the most sear efficient. YMMV
 

Greg_R

New Member
Jan 25, 2012
95
0
0
The best furnaces have two stage variable speed fan motor. They comtinue to periodically circulate the air w/o the furnace kicking on and maintaining a better, more even heat/humidity environment. To me, that is more important than pure efficiency. I just replaced my AC unit with their top of the line, perfectly synergistic with the furnace. Once again, variable speed fan motor. More even cooling, better humidity control and it's the most sear efficient. YMMV
Yes, a VS fan motor (or at least a 2 stage) is critical. Continuous air circulation also helps with air quality (more filtering). I was pointing out that the furnace burner *can* be a separate decision. Some brands (Trane, etc.) only offer the best fan tech in their most expensive furnace. If you're rarely using the gas furnace then IMO the pricey variable gas burner is a waste (but good for Trane's bottom line).

I imagine in NY you definitely need the gas heat during winter so it wasn't something you had to worry about. Where I live in Oregon it is very rare (few days a year) for the gas furnace to kick on to supplement the heat pump. Paying an extra $2k to go from 80 sear to 95+ sear (both units with VS fans) would give me a total savings of $5-$10 a year (not worth it :) ).
 

rockitman

Member Sponsor
Sep 20, 2011
7,097
412
1,210
Northern NY
Yes, a VS fan motor (or at least a 2 stage) is critical. Continuous air circulation also helps with air quality (more filtering). I was pointing out that the furnace burner *can* be a separate decision. Some brands (Trane, etc.) only offer the best fan tech in their most expensive furnace. If you're rarely using the gas furnace then IMO the pricey variable gas burner is a waste (but good for Trane's bottom line).

I imagine in NY you definitely need the gas heat during winter so it wasn't something you had to worry about. Where I live in Oregon it is very rare (few days a year) for the gas furnace to kick on to supplement the heat pump. Paying an extra $2k to go from 80 sear to 95+ sear (both units with VS fans) would give me a total savings of $5-$10 a year (not worth it :) ).

yes, the extremes in temperature are greater here in Upstate, NY for the most part. Temp can hover in the low teens to single digits during the winter and in the 90's during the summer.
 

GaryProtein

VIP/Donor
Jul 25, 2012
2,542
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NY
The most elegant furnace I have ever seen is my friend's gas fired Buderus condensing boiler.
 

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