# Air Source Heat Pump in Minnesota?



## Vikeologist (Sep 5, 2008)

I currently have a 1960's Lennox Oil Furnace.  I am looking to replace it, and was going to go with Natural Gas, but found out, they were not able to get a line up to my house, so that option is out.

I talked to my local plumbing/heating company, and they told me about an air source heat pump.

After talking to him, i talked to some other people, and also did some research online, and some people have told me that air source heat pumps are not a good idea in Minnesota, where the winter temperatures are very cold.

The plumbing/heating company told me that their heat pumps that they install will work down to 15 degrees...then they install a plenum heater or resistance heater, cant remember what he said, and that will kick in and help the heat pump when temps get below 15.

Temps here in Minnesota sometimes never get above 0 degrees in the winter for several days...Is this still a good idea?

Please help, as  winter is coming and I need to get something done here in the next month or so.


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## woodchuck (Sep 5, 2008)

With those temps I wouldn't do it unless electricity for the backup heat was cheaper than whatever else you would put in. Yes it will probably work with even less than 15 degrees but the efficiency really starts dropping around 32 degrees. If you turn your thermostat back at night it won't recover without the backup heat. Our backup heat has to help if the high doesn't get out of the 20's. My heat pump IS about 30 years old but the principal hasn't changed.


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## Vikeologist (Sep 5, 2008)

so what would you recomend in my situation?  So natural gas is out, an air source heat pump is out...

what is left besides propane or all electric?


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## glennjanie (Sep 5, 2008)

Hello Vikeologist:
All hope is not gone, there is still the ground source heat pump. It is a little expensive to install but it will pay for the difference in price in five years.
It sounds like you may be in a rural location with plenty of land. I would recommend that you contact the Rural Electric Cooperative (if you are on that kind of power) because they push geothermal heating and cooling. In our area, for a replacement system, they will finance it 100% and will let you pay for it on your bill over a three year period. When compared with resistance electric heat, a geothermal will make its own payments.
There are different ways to tap the geothermal mass; I used deep wells, there are some in trenches where buried lines circulate the water underground and allow you to use the constant temperature of the earth, some use deep lakes with a circulating coil in the bottom of the water.
It sure is worth checking it out.
Glenn


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## CraigFL (Sep 6, 2008)

I lived in Fairmont,MN for years and had an air source heat pump. It wasn't uncommon to see -35F at night and I can remember one day where it never got above -30F.  We always remember the coldest days but forget that are many days with warmer temperatures too. In spite of what you think, it will still save you money over straight electrical heat.  

Of course it would be better to use geothermal but the initial expense is high. 

One other point is that a cutoff of 15F for a heat pump sounds high. I lived in MN in the 1980s and back then my cutoff was 15F. With the increased efficiency of the units today, I would have expected a much lower temperature.


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## handyguys (Sep 8, 2008)

What is wrong with staying with oil heat? Ask if you can get a more efficient burner/boiler setup? Electric heat is the most expensive option 'round here. Plus you would need ducts. Only advantage in my mind would be easy central AC for the summers.


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## CraigFL (Sep 9, 2008)

handyguys said:


> What is wrong with staying with oil heat? Ask if you can get a more efficient burner/boiler setup? Electric heat is the most expensive option 'round here. Plus you would need ducts. Only advantage in my mind would be easy central AC for the summers.



Have you heard what the price of heating oil is going to be this winter?   And, I assumed he has forced air and not a boiler but we don't know for sure...


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## handyguys (Sep 9, 2008)

CraigFL said:


> Have you heard what the price of heating oil is going to be this winter?   And, I assumed he has forced air and not a boiler but we don't know for sure...



Yea - All energy is going up. Electric, gas and oil. I am not sure if it would be wise to spend thousands to maybe save a few dollars. Bottom line - the OP needs to do the math to see if he will save and if so how long until he recouped his costs. The OP may better spend his money on insulation and other energy saving schemes. Good point on boiler and ducts. around here 99.99% of oil heat is boilers and radiators.


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## Vikeologist (Sep 9, 2008)

I have an Oil Burning Furnace that is forced air, so the duct work is already in place...

Like i said, i spend around $2500/year just on oil alone to heat my house for a bout 6-7 months...

I was told with a geothermal heat pump, I would pay around $400-500 all year to HEAT and COOL my home...

That alone would be enough of a savings wouldnt it?

$2,000/year for 7 years and I would probably have the heat pump paid for.

Any other suggestions?


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## handyguys (Sep 9, 2008)

$500 per year to heat and cool? Sounds too good to be true. I would ask for some documentation on that. Remember, geothermal uses electricity and thats going up too.

Lets say that your number is way off. Lets say it costs 1200 per year, just to be safe. That's a savings of 1300 per year. How much does geothermal cost to put in? $25,000? If it were $25K upfront then you would get a return in just under 20 years (about the time you would need to replace many components). Using those number it wouldn't make sense. On the other hand - If it cost $10,000 to put in you would recoup your investment in under 8 years. I also didn't factor in that your current 2500 does not include your summer AC.

OK - Enough rambling - See if you can get documentation on the operating costs of geothermal in your area and also get some estimates on install.

If the numbers you have are accurate and you can do it on your property I would definitely consider it.


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## Vikeologist (Sep 9, 2008)

I dont have any documentation yet, but the guy giving me the estimate has geothermal, and he heated and cooled his own home for around $800 last year, and his house is much larger than mine. 

Im in a small town, so i do know this guy and how big his house is.

I'm still waiting on the exact estimate, but he thought it would be in the neighborhood of about $13,000.

My local power company will also finance $12,000 of it at 2.9% interest for 5 years.

Im just looking for options, but what else is there if i cant get natural gas?


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## inspectorD (Sep 9, 2008)

What is your house like, There are always ways to improve the envelope before you upgrade the system. Your actually putting the cart  before the horse.
My opinion is to do an energy audit on your home before you upgrade. I have experience in this area and recommend it to everyone before you do a mechanical upgrade. If you do it this way, you save thousands up front that year. To many things go wrong in a home over time, insulation settles or was never installed in some areas ,ductwork works loose, systems get out of wack, the list goes on. I enter a home with an Infrared camera and see the heat leaving building which have an energy star rating. 
Many systems are oversized already because of the envelope not able to support a smaller system. The HVAC company does not have faith in insulators, been like that for years. I don't blame em either.
I don't know how many more ways to say it...you need an evaluation from someone OTHER than a heating guy. 
Sorry if I'm  being forward, but I see it done in the wrong order ALL the time. We need to change that. 

Envelope first, system sized second.
Sorry HVAC guy's.


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## Vikeologist (Sep 9, 2008)

I appreciate you being up front...how much does an energy audit cost?

Also, i have recently replaced the windows, put R-board and new fiber cement siding...

blown in 18" of insulation in the attic...not sure if the walls are insulated or not...


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## inspectorD (Sep 9, 2008)

I would contact as many companies as I can in your area. Try some home inspectors and some HVAC companies for some reputations to go by.
Anywhere from $400 on up. 
Get a company who does infra red thermography and blower door testing. You will save money in the long run, that I am sure of. 
Walls should be insulated, foundation can be insulated, fireplace chimney can be made more efficient. There are many things I would spend money on before upgrading a system.

It does not matter how big and efficient the motor is if your tires do not hold air. 

Educator had an energy audit done , with great results.http://www.houserepairtalk.com/showthread.php?t=3139
and http://dailyhomerenotips.com/energy-conservation/


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## runfast (May 7, 2010)

Here is a page that shows how they work. www.heatpumpmn.com/


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