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Vikeologist 06-28-2008 11:57 AM

Questions about Heat Pumps
I currently have a very old oil furnace. Its a Lennox, probably installed in the mid 1950's. Still heats very well, but the problem I have is with the blower fan motor. It doesnt run fast enough and so it doesnt blow much air out of the ducts. I have tried speeding it up, but its going as fast as it will go.

Question is if I get a heat pump and use my old oil burning furnace as a backup, will the heat pump run off the furnace? Therefor my new heat pump will not be working as well as it should be.

Or would I be better off getting a heat pump and a new natural gas furnace? Only problem there is we are talking about $12,000 for both the heat pump and the new gas furnace.

By the way, I live in Minnesota, so the winters get very cold, so I definately need a backup heat source.

Thanks in advance!

geo 06-28-2008 07:52 PM

heat pumps
do some research but if you want to upgade you should definetly look into a direct exchange geo thermal heat pump these systems can handle all your heat all your ac and about 80% of your hot water all for about 1000 a year. that being said standard practice on a traditional heat pump is to install a resistance heater in the airhandler wired to an outdoor temp sensor which turns it on when the temp drops below eff operating conditions

CraigFL 06-29-2008 06:45 AM

My guess is that anyone that is going to bid/install your heat pump will want a new furnace/air handler because yours is so old. They would be worried that your heat exchanger may be cracked or that the evaporator coil for the heat exchanger may not fit well with your existing ductwork.

You should check oil & natural gas costs in your area but in a lot of places electric is very competitive. This means the suggestion of a heat pump plus electric resistance heating as your backup might be the best alternative.

The geothermal might be nice but if you thought $12K was a lot....

Vikeologist 06-29-2008 07:39 AM

geothermal would be nice, but i cant afford that...

So if i went with a heat pump, and an electric resistance heating, would that be like baseboard heat, or would it still be forced air...

i have never been a fan of electric heat in the baseboard type.

i am new to this so sorry for all the stupid questions....

geo 06-29-2008 11:17 AM

warm air
just like a electric base board eccept the coil is in the airhandler . chances are you wont know the difference between the heat pump and when it switches to the resistance

Vikeologist 06-29-2008 12:03 PM

I have heard that air source heat pumps in Minnesota really dont work that well.

Since the air temp in Minnesota in the winter is below 30 degrees for much of the winter, the savings is minimal.

Maybe it would be better to just put in a natural gas furnace...yes it will cost a bit more to run...but it will take years to make up the price of the heat pump, especially if it is not running all that often anyways..

heat pump in Minnesota would maybe only run October-November, then maybe March-early May.

CraigFL 06-30-2008 05:48 AM

I owned a heat pump in 1983 when I lived in Fairmont,MN. This was in the time when heat pumps weren't as efficient as they are now. Mine changed to alternate heat(electric resistance) at about 16 degerees back then. Your changeover point will depend on your units efficiency and the cost of electric. I think you would be surprised at the savings. Even with the occasional -35F in Fairmont, heat pump still worked on those days where temperature warmed up some...

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