Modern Heat Pumps in a Northern Climate?

[Matt Meiser]

One of the HVAC contractors I had out to quote doing a gas conversion started telling me about heat pumps. At first I thought he was crazy, but apparently a number of people in my are have installed them. He's claiming incredible energy savings and 4-5 year paybacks.

My only heat pump experience was in the mid 90's when I lived in an apartment in Indiana with a heat pump. Once it got down to freezing the electric kicked in and burned up the bearings in our electric meter. Apparently things have changed quite a bit. First they are installed with a gas furnace, and second, they work down to 20 degrees he says. Even in January, our average temperature is 23 so in an average January the heat pump would be in use more than 1/2 the time.

So, who has one?

[Stephen Tashiro]

I have no experience with heat pumps in a northern climate, but let me ask how deep the contractor intends to put the line that gets heat from the deep soil? I think the theoretical effectiveness of the pump depends a lot on that depth. I also think that people usually consider it impractical to go down to the depth where the soil has a constant temperature all year. So the economics of how deep the line can be laid are important.

[Brian Elfert]

Presumably Matt is talking about air source heat pumps, not geothermal.

The old rule of thumb used to be 32 to 40 degrees was the lowest an air source heat pump could handle. I have heard as low as zero degrees now days, but I suspect the heat pump is not running the most efficient at those temps.

[Tom Godley]

Heat pumps are much more efficient than they were just a few years ago -- obviously the efficiency drops as the temperature drops but the relative cost at any temp depends on the alternate energy source being used.

Matt what you are describing is a duel fuel set up -- you run the heat pump to its design efficiency and then you use the gas furnace to provide for the space when the temperature drops below this point or if you require a rapid rise in temp. The old systems were electric resistance -- they had a large heating coil -- essentially electric heat.

The systems with variable speed fans and either two speed or inverter compressors are the most efficient.

[paul cottingham]

I run my heat pump without any backup, and I get heat all the way down to around 22 degrees Fahrenheit. Its a monster, but it works great.

[Paul Ryan]

I use an air source heat pump for 90% of my heating here in the artic of MN. I do not have the room for geo-thermal. I have it set to heat run down to 0 degrees. However I really have 3 heating options, heat pump only, heat pump+electric booster, and gas. The gas only comes on when the elec. company shuts off electic (it is a metered system) or if it gets below zero out. The heat pump runs by itself down to 20 degress, and the heat pump uses the electric booster between 20 and 0. It is a real good system and should pay for itself in about 4 years. I lving in a rural address the electric coop provides a reduced rate on electricity metered and gave me a $800 rebate to install the heat pump. I was able to use my existing gas furnace. The heat pump with the electric booster is still cheaper for me to run than gas was 2 years ago. 2 years ago contracted gas would have been $2.30 a gallon for LP, where I am paying about .065 a kw. LP needs to be around $1.10 a gallon to break even with what the heat pump set up runs me. I also use an electric water heater that is 80 gallons and runs me about 1/2 the cost per year than what my 40 gallon gas water heater ran me. I think heat pumps are a great idea, electric is going to rise but so it LP. And electricity is being produced in more and more ways where LP fluctuates much more with the market. My local coop quoted my $1.90 a gallon for contracted LP for this comming season. I went from burning about 1100 gallons of LP a years (heat and water heater) to about 170 gallons last year even though this was one of the coldest winters in a long time.

[Matt Meiser]

Yes, we are talking air source heat pumps. We are limited on efficiency unless we want to replace the 1 year old furnace but can go to a 15 Seer unit. Beyond that they want a variable speed furnace.

Paul, what happened to your electric consumption when you installed the heat pump, percentage wise?

[Al Willits]

I'd think comparing BTU costs versus each source of heat would be the way to start.

Here in the Metro area Nat gas if by far cheaper than heat pumps, maybe not so in the area's that use Propane or electic resistance heating.

Also then consider maintance and warrtanty/service maybe?

Al

[Mac McQuinn]

Matt,
I'm up by Saginaw and my Son lives around Lexington, Kentucky. He has a heat pump on his new house. It's louder than my Forced air furnace and cost an arm and a leg to operate when temps get below freezing. It relies on electric heat below that temp. He said never again, perhaps in a more moderate climate where the unit does not have to go to electric heat mode so much. Kentucky can get cold, Several times this winter, his temps were actually colder than ours. Perhaps in a area where electricy is cheaper than Michigan, it would be a viable option in colder climates.

Mac

[Ken Garlock]

HI Matt. I have a geothermal system which was installed when we built our home. Here in Texas we have the flip side of your problem. How big does a system need to be to cope with 110 degree days?

Our system consists of a 5 ton compressor by "Water Furnace", a Trane evaporator, 3 independent zones, and 4 geothermal wells, each 300 ft. deep. The well need to be deep enough to be in soil that is of constant temperature the year around. In our case it is in the 60 degree range, and that requires drilling 300 ft. WE do not have supplemental resistor heat. This last winter it got down to 9 degrees and the 3200 sqft house maintained 68 deg.
Yes, I realize that 9 is nothing compared to your weather, I grew up in Ohio where I once experience a 27 below night.

I hope that Lee Schierer will comment, he lives near Erie Pa. and give you a good valid opinion about geothermal in the cold north.

[David G Baker]

Matt,
Have you researched Geothermal heat and cooling? The initial investment is more but in the long run it may be considerably less than other heat sources. There are several ways to accomplish a geothermal set up and it is absolutely essential that you find the right contractor to do your work because there are some snake-oil folks in the business.

[Paul Ryan]

Matt,

My electric usage went up. It basically trippled my electric bills for Jan, Feb, and March. My normal electric bill is $100 when very little heat to no heat is used. In Jan. and Feb my bills were $300. The later half of Dec added about $100 and the early part of march added about $100. In the summer the heat pump saves me about $30 per month if the AC is used heavily because it is much more efficent than the old AC unit. I also have a 15 seer unit. I could have went up to 19 if I wanted to replace the furnice. My furnace is a newer carrier unit. I am very happy I did it, but you need to crunch the numbers. I am not sure the conversion between natural gas and electrcity. But as I said earlier if you buy electicity for about .0065-.007 kw LP needs to $1.10 to be equal. Changing my water heater to an electric save me a ton of money as well. Gas water heater are very ineffiecient around 70-80% but usually make up for it because gas is cheap. But an electrical water heater is 100% efficent and being on a reduced rate save me a lot of money. We needed a larger water heater also. My wife's 90 gallon tub takes a lot of hot water to fill.

[Matt Meiser]

I was researching geothermal with the plan to do that in a few years. Then our furnace went out one cold day last year and had to be replaced RIGHT NOW. I was telling the contractor that came about this and that's when he told me about the new heat pumps. They are no longer the all-electric system Mac talks about.

The contractor tells me that the really high SEER units rival Geothermal for our area. "Splitting hairs" different in his words but a lot cheaper to install.

[Larry Edgerton]

Matt, how well insulated is your house? This is the first place to look for efficiency, heat loss.

I recently restored a 3600 sq. ft. home and cut the fuel costs by a little over 50%. An extreme example, but considerable savings are common.

The 130 year old house in Jackson I am working on now has seen considerable savings, hard to say just yet as we were improving all winter, but they saw smaller bills than they have ever seen as we progressed with new windows, Sturdy R wrap, and tightened up all of the areas shown up in the thermal imaging. A thermal scan is a relitively low cost way to attack the problem, usually in the $500 dollar range, pinpointing exactly where your house is losing heat.

With a thermal scan in hand there are many things you can do yourself to tighten up. If you want I can give you the number of the fellow that I used down here for the house in Jackson.

My own house is 1000 sq. foot, and my nat gas heat bill is about 70-80 dollars in the worst months of the winter. I plan on cutting that in half on my new house, again a 1000 sq. ft. house, but built to be efficient from the ground up.

As far as air heat pumps, up North they are not really viable, but we are a little colder than you. I would still be leary of there ever being a payback, especially as the system is more complicated, so will have more maintainance costs as it grows old.

Insulation never breaks, keeping what you have paid for [heat] in the house has always been to me the best investment.

[Matt Meiser]

Larry, the house is 19 years old with 5 year old Anderson 400-series windows. We re-insulated the attic and insulated the rim joist last fall and replaced a couple skylights with broken seals between the panes (among other problems.) We also enclosed the previously open basement stairs that lead to a currently unfinished basement at the insulator's recommendation. This seems to have made a huge difference in our gas consumption over the winter, to the tune of the gas company owing us $800 back on our pre-buy. I thought maybe it was warmer this winter but we are way behind where there computer says we should be. And I know I left the heat on high (60 instead of 40) in the shop for a couple weeks straight and needed an extra fill in that tank. The insulator's next recommendation was to insulate the exterior walls in the basement which we will eventually do but not for a while.

The thermal scan sounds interesting. I assume they can they only be done in the cold months? Ballpark pricing, what do they run?

At some point we'll have to replace our AC unit and he said the heat pump is only about 15% more than an AC only unit. The heat pump quote is about $4100 +/- 300 depending on whether we need 2.5 or 3 ton which would be determined by heat loss calcs they will do if we get serious. For giving me quotes he used the size of our current AC and used the square footage rule of thumb to check that it was sized at least close to where it should be--not a safe assumption since the previous homeowner put it in himself with the help of a son-in-law in the biz.