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My heat pump
My heat pump
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Old 9th February 2018, 03:32 PM   #21
TheGimp is offline TheGimp  United States
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I think my last electric bill was $240, and I burned about $40 in fuel pellets. 2400sq-ft floors pace, with an additional 600sq-ft for the garage, which I keep heated to about 55f.
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Old 9th February 2018, 06:31 PM   #22
Tubelab_com is offline Tubelab_com  United States
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I wouldn't fool with wood, or pellets, or other survivalist type stuff, personally. There could be insurance issues
We had our house built by a "budget" builder. The exterior walls are mostly plastic (styrofoam panels) with wood in the high strength areas (corners). All very flammable.

If I were to build some type of auxiliary heat, the combustion system would be located well away from the house. There is a guy about a mile down the road from me who has a cube shaped steel box about 6 feet on a side with a chimney sticking out of the top. It sits away from his house and barn but is always smoking in the winter. I need to stop in and see what it's doing. It could be heat for his barn since he has cattle and chickens....lots of chickens, fresh dead ones on the road every few days.

First upgrades will be insulation in the basement. That's where my lab is and spend quite a bit of time here. I keep one end of it heated to somewhere in the mid to high 50's. I'm sure a lot of that heat is wasted through the concrete block walls.

Get a different controller.
The heat pump and controller are what the builder provided, which is again budget stuff, probably the minimum EER. The controller does seem to have some intelligence. It will engage the heat pump first under normal operation and then turn on the electric heat if the inside temp doesn't drop after trying heat pump only for a while. When the heat pump goes into defrost mode every 5 minutes, it also turns on the electric heat. This can happen even if the outside temp is in the low 40's and it's raining.

When my wife isn't home I keep the house at 63 degrees or less. When she gets home I turn it up to 68 for a while, then 65 overnight. I have learned to raise the thermostat in 1 degree increments. A quick change in setting will bring out the coat hanger!

the garage, which I keep heated to about 55f
We had insulation installed in the walls between the garage and the house, but there is no heat in the garage. The water that dripped from the snowblower due to engine heat is still frozen on the garage floor. My wife won't go in there. The cars are kept outside.
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Old 9th February 2018, 07:40 PM   #23
Ripcord is online now Ripcord  United States
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Originally Posted by w5jag View Post
Get a different controller. Our second house uses a heat pump and the thermostat controller has two heat positions - one is for heat pump only, the second engages the electric heat bar.
I like this idea. Not sure about the wiring though. Here is a picture of my thermostat. The resistive heat element turns on automatically. Is it possible that it is controlled by one of the mercury switches?
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Old 9th February 2018, 07:54 PM   #24
TheGimp is offline TheGimp  United States
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I have a bypass switch for my emergency heat strip, so I can force the heat pump to run by itself. I keep the EHS off except when the outside temp is below 12F.Above that temp, the 15.8 SEER heat pump is supposed to be above 1:1 on efficiency. (1:1 is the point where the energy consumption of the heat pump is equal to the heat capacity for pumping heat.)

I think Fujitsu claims they have one that doesn't go below 1:1 until it gets below 0F.

I have a NEST thermostat, and have the temperature programmed with slow increases from 7 in the morning until around 1pm (66F), then hold until around 8pm and gradually start back down again at night (to 62F).

I don't mess with the thermostat.
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Old 9th February 2018, 08:01 PM   #25
Juergen Knoop is offline Juergen Knoop  Germany
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Is your heating system correctly adjusted? Maybe there is room for improvement, like lowering the temperature inside the heat storage and exchange tank (boiler?), thus the heat pump would see a lower temperature difference and operate at higher efficieny?
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Old 9th February 2018, 08:03 PM   #26
mike567 is offline mike567  United States
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the thermostat is held on with 6 captive screws located thru holes around the bulbs and pivot.
Loosen the screws and the thermostat will seperate from the subbase. the heat strips will be controlled from the lower bulb through the w2 terminal on the subbase if i remember correctly. that t-stat is at least 15 years old.
Note :
the strip heat is staged in behind the heat pump by 1.5 to 2 degrees.

Tubelab: If your heat pump is defrosting every 5 minutes it is broke. Small control board in outside unit may have jumpers or dip switches to adjust the defrost interval. Also improper freon charge will play havoc. Cycling on pressure switches will some times seem like defrost mode.

Last edited by mike567; 9th February 2018 at 08:12 PM.
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Old 9th February 2018, 09:15 PM   #27
billshurv is offline billshurv  United Kingdom
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My heat pump
It's funny, when I saw the Tongan flag bearer at the winter olympics opening ceremony I immediately thought of George. 23F...nah don't need a shirt
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Old 9th February 2018, 09:48 PM   #28
kevinkr is offline kevinkr  United States
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My heat pump
We have natural gas and a moderately well insulated antique house, and last month we had a $500 gas bill. It was a rather cold month even for January. We have a modern "high efficiency" steam boiler, and steam heat is not particularly efficient, this boiler has an AFUE of about 84% which is about as good as you can do without superheating which is only available in larger boilers. There is no energy star option.. It does keep us comfortable for the most part.

My parents have lived with heat pumps since the early 1980s and used supplemental heaters scattered around the house to avoid resistive heat. The concern I think with running the heat pump at low temperatures is you are not getting a lot of heat and while the cost relative to resistive heat might be attractive in the short term I wonder what the effect is on compressor service life - i.e. if it shortens the life of the compressor by several years the savings may be negated by early replacement.
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Old 9th February 2018, 10:05 PM   #29
Ron E is offline Ron E  United States
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Originally Posted by Ron E View Post
1 Therm = 100000 BTU = 29.3 kW-hr
Costs perhaps $1 as natural gas, and roughly $3-3.50 as electricity.
Figure above is electricity at ~$0.10-0.12 per kW-hr, as it is here.

Looks like cost for propane is close to electricity, as it is ~$2.6 per gallon and a gallon is 1/1.09 therms - so roughly $3 per therm, but variable.

I have a drafty 59 year old house with not a lot of insulation, my bill for heating and electricity combined is (in Minnesota) ~$180-200 in the worst months. 96% Natural gas forced air furnace. Temp setpoint 68 when home, 60 when not.
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Old 9th February 2018, 11:40 PM   #30
PRR is offline PRR  United States
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Originally Posted by Ripcord View Post
....heat pump. ...below a certain temperature a resistive heat coil turns on .... Very inefficient. .... What makes heat while drawing little current? I thought about disconnecting it ...
There is no free lunch.

Electric heat is 100% efficient. (Minus much of what you lose in leaky poor-insulation ducts in attic/cellar.)

Heat-pumps *exceed* "100% efficiency". They pump heat uphill. To a point, an electric freon machine can pump-up more heat energy than the electric it sucks. (Still no free lunch: you are making the outside colder.) But there is a limit, where efficiency drops below 100%, and electric would as good and less mechanical wear/tear. Sadly this limit does not cover your coldest days/month. The heat-pump company in Maine went out of business, possibly because he over-sold the benefits and the poor pumps died trying to cover January.

But we do NOT really (individually) care about "efficiency"! As you say, it is COST. George could move up in the hills and get scrap coal for free. It may not burn well, he may not get 20% of the potential heat in the coal, but FREE! I just cut 20 large trees, more wood than I know what to do with, I could build a bonfire in the yard and capture 1% of the "free" heat through my windows. (But just bucking-up big trees is real work and expense.)

Above "a cold day in the northern US", a heat-pump can run over 100% efficient, but on expensive electricity. For long periods of spring and fall, it is the cheapest to run (unless you can find free or very-cheap fuel).

Coal is cheap per ton in large quantities. The burner is expensive, labor-intensive, not efficient in small sizes, the smoke and ash are dirty. Coal was THE fuel until over-exploited coal miners tried to upset the economics and basically pushed all small burners to oil fuel (car fuel byproduct).

In much of the US, pipe-gas is cheap per BTU and the burner is inexpensive. If available, this is usually your Best Deal.

For small occasional heat where pipe-gas is not at your house, electricity does OK. Especially because past policy has left some very low electric rates in pockets of the country (TVA, Oregon).

For larger loads, Fuel Oil and Propane compete. They both come on a truck so are available almost everywhere. Propane looks cheaper per gallon (most winters) but has only 2/3rd the BTU per gallon of Oil. Oil smoke has sulphuric acid so is not worked to high efficiency (exhaust temp well over 212F, leaving much heat un-caught); Propane is generally cleaner and my heat exchanger exhausts at 110F (drippy) and just warm enough to warm the house. I believe a 95% propane burner equals +/-10% a "85%" oil burner on cost, depending on market. (And I'm in an Oil market, my best propane price is high.) 80% gas burners are also available a bit cheaper, and seem to make sense in Texas and other places where gas is cheap or loads are not-large.

> disconnecting it ...

There's a big wire going to that coil. Find a switch or disconnect a wire. (Do not get killed or burn down the house!!) Your heat pump will moan and moan. It may be able to pump-up some more than it does. (However that thermostat suggests it is already getting cold in the house, heatpump maxxed-out, by the time the coil is cut in.)

Your next step would be to replace the electric coil with a fuel burner. Electricity is much "too good" to use for heat; it's just easy/convenient. Coal oil gas etc give much more BTU per $. Just as before, you run the heat-pump until it can't keep-up, cover the difference with fuel. However that coil is maybe $50. If you could buy a fuel furnace without the house-fan it would be $500+; over $1000 installed for gas, $2000 for oil. Are your heating costs that bad? (Yes, they sure can be; you may have been over-sold on that heat-pump.)
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