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Discussion Starter · #1 ·
Hi folks. I am building a new home and have to decide on whether to use a heat pump or central air here in St. Paul, MN. I know how each works and the theory of why they work. I am in USDA climate zone 4a. We normally have about 2 weeks of fall and 2 weeks of spring where the outdoor temperature is between 25 and 45 degrees F. From mid April to mid Nov the outside temperature is between 40 and 100 degrees F, with extremely high humidity from June through Sept. From mid Nov to mid April the temperature ranges from -40 degrees F to 70 degrees F with a relative humidity of about 15%.

My question is which system would work most efficiently/effectively in this climate without regard to the discussion of electricity or gas cost / usage? Geo thermal costs about $25K so this is not even an option. Any opinions based on actual personal usage of a heat pump in this climate zone would be appreciated.

Thanks,

Ken
 

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Without consideration of operating cost.

Hard to have any real discussion about it.

If operating cost is not a concern. Then electric baseboard in each room.
 

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Discussion Starter · #3 ·
Thanks for the reply beenthere

As I stated in the post, the question posed is which system would work most efficiently, effectively in this climate; not a about the cost which is based on KWH / therms and varies from supplier to supplier. Thanks again for your reply.:thumbsup:

Ken
 

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The best of all worlds is the Dual Fuel set up. Gas Furnace and Heat Pump.

Cooling is cooling, the heat pump will not be any more efficient as an air conditioner. With your winter temps and short daytime/low sun angle for heat accumulation, you will spend most of your day loosing the heat pump battle and will either be running aux electric heat or the gas furnace back-up.

The 30 days of combined spring/fall that you get would of course be great for the heat pump, but in my estimation, the cost savings is barely worth the upgrade from a standard AC unit.

If it were me, and I was building NEW, I would insulate the heck out of the house, and go with a high efficient 16SEER AC (or higher depending on budget) and solid 93% (or higher) gas furnace.

Good Luck.
 

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Since electric baseboard heat is 100% efficient. It would be very efficient.
 

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We normally have about 2 weeks of fall and 2 weeks of spring where the outdoor temperature is between 25 and 45 degrees F. From mid April to mid Nov the outside temperature is between 40 and 100 degrees F, with extremely high humidity from June through Sept. From mid Nov to mid April the temperature ranges from -40 degrees F to 70 degrees F with a relative humidity of about 15%.
Use your outside temps along with your COP
http://en.wikipedia.org/wiki/Heat_pump
to figure your energy-in/energy-out ratio.

Removing humidity, but not too fast, is another matter.
 

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I'd put in a nice Modulating 98% gas furnace.
With 2 stage A/C.

Comfort baby, comfort.
 
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