Techtechheatpumpshousecold

Sat Feb 4, 2017, 11:35 AM

Heat pump replacement

Any thoughts on a way to keep my house warm when it gets like this?

Technically I'm in the south just barely below the Mason-Dixon line. High today supposed to be 25, been like this for a couple days now. Anytime it gets like this the pump just stays on, house is set to 68.

The pump seems to work okay as long as it stays above freezing, but if get's to single digits, forget it "emergency heat" stays on.

Not an oil fan, and the nearest gas pipe is about a mile away.

Thanks

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Arrow 9 replies Author Time Post
Reply Heat pump replacement (Original post)
def_con5 Feb 2017 OP
fszwfnj Feb 2017 #1
BuzzClik Feb 2017 #2
Aldar Feb 2017 #3
KAT Feb 2017 #4
fszwfnj Feb 2017 #5
Daves Not Here Man Feb 2017 #6
def_con5 Feb 2017 #7
It Guy Feb 2017 #8
oflguy Feb 2017 #9

Response to def_con5 (Original post)

Sat Feb 4, 2017, 11:38 AM

1. Have you thought about a pellet stove to supplement heat on very cold days

Not very expensive and easy to operate as long as you don't mind lugging 40-pound bags of pellets into the house a few times a week.

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Response to def_con5 (Original post)

Sat Feb 4, 2017, 11:38 AM

2. We use our fire place.

We get about 5 to 10 nights per year below 35, and one or two below 25. The fire does a nice job keeping things warmer and taking the stress off the heat pump.

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Response to def_con5 (Original post)

Sat Feb 4, 2017, 11:40 AM

3. I have a heat pump

when it was installed, they also installed a 15kw strip heater in the fan unit. It can keep the house warm down to 20 or so. I live in Texas.

Try a kerosene catalytic heater. We have one of those for emergencies, puts out 23000 BTU, runs about 20 hours on 1.5 gallons of K1 kerosene. Can heat the front part of my house with it.

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Response to def_con5 (Original post)

Sat Feb 4, 2017, 11:42 AM

4. Wood or propane.

 

You can get a ventless propane heater pretty cheap. I have a NG one and it cranks out the heat.

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Response to def_con5 (Original post)

Sat Feb 4, 2017, 11:42 AM

5. I have one of these as well

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Response to def_con5 (Original post)

Sat Feb 4, 2017, 11:45 AM

6. I second the pellet stove.

We've had a few. I bought them off Craigslist. Very reliable and easy to clean. You can get the smaller ones and they'll warm up your place nicely. I had one in my old house as my main source of heat with kerosene as a back up. At $250 a pallet (50 bags) it was waaay cheaper.

We bought another one after we moved to a new home. I turned the garage into a den of sorts and needed a heating source. The thing kicks ass.

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Response to def_con5 (Original post)

Sat Feb 4, 2017, 11:52 AM

7. Thanks all

Lots of good options to consider. I'd never heard of a pellet stove. Gonna check it out.

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Response to def_con5 (Reply #7)

Sat Feb 4, 2017, 01:18 PM

8. The other thing to consider would be to bury a hundred yards or so of the evaporative line in

the earth. It acts like an earthen heat source as the earth just a few feet down remains at 55 deg F. That's plenty of latent heat to do the job. These lines can be either vertically placed, 10 feet down or so or laid out in a grid pattern 2 to three feet down

In the summer and when the coolant flow is reversed, the earth acts as a heat soak, again supplying 55 deg differential, which is much more efficient than shedding heat in 100 deg F air.

This system is called geothermal heat pump.

https://energy.gov/energysaver/geothermal-heat-pumps


Geothermal heat pumps (GHPs), sometimes referred to as GeoExchange, earth-coupled, ground-source, or water-source heat pumps, have been in use since the late 1940s. They use the constant temperature of the earth as the exchange medium instead of the outside air temperature. 

Although many parts of the country experience seasonal temperature extremes -- from scorching heat in the summer to sub-zero cold in the winter—a few feet below the earth's surface the ground remains at a relatively constant temperature. Depending on latitude, ground temperatures range from 45°F (7°C) to 75°F (21°C). Like a cave, this ground temperature is warmer than the air above it during the winter and cooler than the air in the summer. The GHP takes advantage of this by exchanging heat with the earth through a ground heat exchanger.

As with any heat pump, geothermal and water-source heat pumps are able to heat, cool, and, if so equipped, supply the house with hot water. Some models of geothermal systems are available with two-speed compressors and variable fans for more comfort and energy savings. Relative to air-source heat pumps, they are quieter, last longer, need little maintenance, and do not depend on the temperature of the outside air.

A dual-source heat pump combines an air-source heat pump with a geothermal heat pump. These appliances combine the best of both systems. Dual-source heat pumps have higher efficiency ratings than air-source units, but are not as efficient as geothermal units. The main advantage of dual-source systems is that they cost much less to install than a single geothermal unit, and work almost as well.

Even though the installation price of a geothermal system can be several times that of an air-source system of the same heating and cooling capacity, the additional costs are returned to you in energy savings in 5 to 10 years. System life is estimated at 25 years for the inside components and 50+ years for the ground loop. There are approximately 50,000 geothermal heat pumps installed in the United States each year. For more information, go to:


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Response to def_con5 (Original post)

Sat Feb 4, 2017, 02:09 PM

9. def_con, are you the same guy on here that said his A/C unit would not cool your house

Last edited Sat Feb 4, 2017, 02:53 PM - Edit history (1)

this past summer?

Air source heat pumps extract heat from the air outside and transfer it inside the house in the winter. Of course, the colder it gets outside the less heat is available in the outdoor air and the air cooled HPs efficiency suffers.

Essentially what an air source heat pump does is change what is the indoor coil in the summer to the outdoor coil in the winter and changes the outdoor coil in the summer into the indoor coil in the winter. Instead of capturing heat inside the house and expelling it outside, which is what every other "normal" A/C unit does in the summer, an air cooled HP functions the same way in summer, but captures outside air heat and expels it inside your house in the winter. This is done by reversing the flow and thus the role of the refrigerant from season to season.

A troublesome situation develops with air source HPs in the winter. Because the outdoor coil is operating below 32 degrees, it tends to "ice up" or form a layer of ice on it. As you can well imagine, a thin layer of ice on the outdoor coil is detrimental to heat exchange, so on either a timed basis or due to a thermometer imbedded in the outdoor coil, the HP returns back to its summertime mode whereby it ABSORBS THE HEAT YOU JUST PUT INTO YOUR HOUSE and sends it outside to melt the ice! While this is happening, your "emergency" heat strip comes on to temper the cold air coming out your air registers so you don't freeze to death.

So you can see why air source HPs are not good candidates for northern climates.

The better choice (in all climates) is a water source HP. Now, the HP uses heat from the ground to heat your house and dissipates heat into the ground in the summer to cool it.

You didn't say which type HP you have. One possible solution would be to find out what KW your electric "emergency" heat is. Some installers go lean on the "emergency" heat because they are not concerned so much for your comfort in winter if they think it never gets real cold in your locale. They are sometimes more focused on how much heat you need only while the HP in in the defrost mode. If your electrician ran a big enough wire to the indoor unit, you might have gotten lucky enough to simply add more heat strips. (they come in 5KW increments and are relatively inexpensive and easy to install). Of course heating your house with electric strip heaters is expensive, but if it only gets real cold for just a few days a year, this might be more appealing to you than hassling with a big ole oven and the fuel it requires.

Feel free to ask questions.

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