Heat Pumps and Electric Heating - Heat pump Efficiency
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Willyp923
02-25-06, 07:10 PM
So i have been in the heat pump forum reading for an hour or so, and have learned quite a bit. However i have a couple questions. How efficient are Heat pumps, if they run for long periods using lots of electricity? are they comparable to a 90% efficient furnace?or is that comparing Apples to oranges?
Do you have to have a back-up system for really cold days? or would 2 heat pumps do the trick?
When people talk about balance temp for a dual system, that is the temp. at which the heatpump would (As calculated) not be able to keep up and would shut-down, but if you set it really low as 10 Fah, it would just get cold in your house right?, the heatpump wouldn't freeze up because it is not designed to run at that cold of temps? So if you didn't have a backup system just a couple of space heaters that would help the heatpump keep up on extremely cold days, is this inefficient and stupid?
I hope you can understand my questions, i am really uneducated about heatpumps but am planning to build an extremely efficient house with solar panels and the whole KABANG, and want to find the best system. I live in nothern ohio, as low as 5-10 during Jan/Feb with lots of wind.
Being an electrician you would think i would know a little more about this stuff but not many people are putting heatpumps in yet. I like it when home-owners tell me to do a job the way i would if it were my house, since i enjoy doing things correctly and knowing they don't want to skimp on things, So i am asking all you heating guys, if it were your house without budget what would you do?
Thanks Guys
Do you have to have a back-up system for really cold days? or would 2 heat pumps do the trick?
When people talk about balance temp for a dual system, that is the temp. at which the heatpump would (As calculated) not be able to keep up and would shut-down, but if you set it really low as 10 Fah, it would just get cold in your house right?, the heatpump wouldn't freeze up because it is not designed to run at that cold of temps? So if you didn't have a backup system just a couple of space heaters that would help the heatpump keep up on extremely cold days, is this inefficient and stupid?
I hope you can understand my questions, i am really uneducated about heatpumps but am planning to build an extremely efficient house with solar panels and the whole KABANG, and want to find the best system. I live in nothern ohio, as low as 5-10 during Jan/Feb with lots of wind.
Being an electrician you would think i would know a little more about this stuff but not many people are putting heatpumps in yet. I like it when home-owners tell me to do a job the way i would if it were my house, since i enjoy doing things correctly and knowing they don't want to skimp on things, So i am asking all you heating guys, if it were your house without budget what would you do?
Thanks Guys
Ed Imeduc
03-21-06, 02:58 PM
Well first you want to look at fuel cost for where you are there. Go to
http://www.warmair.com/ and find out what fuel is best for you there.
Down here in Mo all we put in are heatpumps for heat. Now cost ,electric heat is 100 % no loss. So say you pay $1.00 for a kw and it goes in a electric furnace. If you put that same $1.00 for a kw in a heatpump at around 30o outside you will get 3 times more heat for that same $1.00kw
Now like the SEER ## on a AC we have a HSPF### for the heatpump.
The higher the SEER and HSPF are the more the units will cost. So you have to look at where to stop on cost there so you get a payback over time.
Id say its all in how the home is built to how cold outside the heatpump will still heat the home. Anytime the pump cant keep up with the home the electric elements in the unit will come on and heat the home.
Now a heatpump can be put on top of a gas furnace so you have AC and heat from it and you set an outdoor tstat that will turn the heatpump off say at 25o and the gas furnace take over below that. If it warms up the the heatpump will come back on
Hope this helps if not post back here in same post.
ED;)
http://www.warmair.com/ and find out what fuel is best for you there.
Down here in Mo all we put in are heatpumps for heat. Now cost ,electric heat is 100 % no loss. So say you pay $1.00 for a kw and it goes in a electric furnace. If you put that same $1.00 for a kw in a heatpump at around 30o outside you will get 3 times more heat for that same $1.00kw
Now like the SEER ## on a AC we have a HSPF### for the heatpump.
The higher the SEER and HSPF are the more the units will cost. So you have to look at where to stop on cost there so you get a payback over time.
Id say its all in how the home is built to how cold outside the heatpump will still heat the home. Anytime the pump cant keep up with the home the electric elements in the unit will come on and heat the home.
Now a heatpump can be put on top of a gas furnace so you have AC and heat from it and you set an outdoor tstat that will turn the heatpump off say at 25o and the gas furnace take over below that. If it warms up the the heatpump will come back on
Hope this helps if not post back here in same post.
ED;)
airman.1994
03-21-06, 07:56 PM
Sounds good to me!
thermofridge
03-22-06, 09:21 PM
Youre an electrician so you should understand this. At, say, 55 degrees your heatpump is running and drawing 12 amps. Thats not bad considering its not gonna run long to get the house to temp. Now go to 30 degrees. Because of the refrigeration process, the compressor motor actually draws less amps because the difference in the high and low pressure is less. So, as it gets colder, less amps so it can run longer for the same price. Now your question. If it were my house with no budget, I would forget about an air source pump and go with a water source pump. As a matter of fact I have one. In the coldest month of winter, I spend under 100 dollars a month to heat my 1400 sq ft home. There is no substitute. It is by far the most economical system you can have. Oh, and I live in Wisconsin about 50 miles north of Madison. With a water (or groud source) heat pump, the compressor always draws relatively the same amperage because it is using the earths warmth the whole time. For air conditioning, it could be 120 degrees and the pump would be idling along while outdoor condensers would be exploding. Remember, refrigeration doesnt make cold, it moves heat and with this system the multiplier is approximately 4. In other words, buy a Kw and get 4 Kws of heat in return. In other words, its 400% efficient. Hard to believe but its true.