Know Anything About Heat Pumps?

Thud · November 13th, 2004, 09:56 PM

We moved into a new house early this year, and it is equipped with a heat pump rather than a more typical air conditioner/furnace setup. I'd never even seen one 'til we moved in here, so I know very little about them.

Right after we moved in, the fan on the unit quit (unbeknownst to me), so we were on "emergency" heat. That means the the only heat getting to the house was being generated by electric coils inside the air ducts. This came to mean a couple of massive electricity bills.

When we were on the emergency heat, a red light on the thermostat came on. Now the we've started to run the heat again, there's a green light on the thermostat that says "auxhillary heat". I'd assume a green light to be "good", but I don't believe the fan on the outside unit is running. At least I can never catch it running.

So can someone offer me some insight here? Are we in for a whopper of an electricity bill again, or is this normal?

Redwolf · November 13th, 2004, 10:10 PM

I'm guessing auxilliary heat means you have either a) a gas-powered backup or b) and electric powered backup (just a guess, check it out). It's better than the way it was though. Heat pumps are notorious for not really being 'heat' pumps, and costing lost of money when theres not alot of heat to 'pump'.

RADAR1797 · November 13th, 2004, 10:13 PM

Heat pumps become almost useless under 30 degrees. I remember being out in the field with our ECUs (aka heat pumps) and when it dipped down below 25 the stopped heating. The coils were frozen over and we had no heat until we "acquired" some fuel burning heaters.

-RADAR

TOAD6147 · November 13th, 2004, 10:22 PM

Auxiliary or Emergency heat both use the electric strip heaters as opposed to the reverse cycle of the compressor. Emergency is just that: if the compressor fails to work, at least you have the strip heat to keep warm. They are also used when the outdoor unit goes into defrost to temper the cold air being blown out of the ducts. When the unit goes into defrost it's just like running in cooling mode except that the outdoor unit condenser fan does not run. When it changes cycles like that you should hear a loud hiss which indicates the reversing valve has been engaged. Shortly after that, it's common to see a lot of steam coming off the outdoor coil as the hot gas starts to melt the ice. Auxiliary heat refers to when the heat pump can't keep up with the demand for heat that you're asking for. If the differential between the t/stat setting and the room temp gets usually to 3 degrees, then the electric strip heat will kick in to help maintain the desired temp. Did you say this was a "new" house that you bought? If so, you need to have the A/C people come back and check it out. it should have a one year parts a labor warranty unit wide with up to at least 10 years on the compressor. Have you checked the breakers and disconnect at the outdoor unit?

Redwolf · November 13th, 2004, 10:28 PM

/\ If what he says is true (assuming it is, oh master of the heat pump), I'd be calling the A/C people right about now, even if the house is actually not 'new' but left over from the early colonial period.

TOAD6147 · November 13th, 2004, 10:51 PM

It's true in the colder climes that heat pumps were added on to gas or oil-fired furnaces. In those situations then the fossil fuel was used for emergency/auxiliary heat.

Redwolf · November 13th, 2004, 11:29 PM

I thought there was something like that. We looked at installing a heat pump and one of the options was a 'gas pack', or basically a small gas furnace for when there is no heat to draw from the outside. The A/C guy we asked about this called it an 'auxillary heat source'. I guess these 'heat strips' would do the same thing, just with electricity. Makes sense...

samwichse · November 14th, 2004, 01:48 AM

Yeah, heatpumps are the worst. The colder it gets outside, the colder it'll get inside, that's just the way it goes.

If a gas line isn't availible in your area, I'd recommend looking into getting a propane installation, it's surprisingly affordable, and will eventually pay for itself while making your house WAY more comfortable.

ted61 · November 14th, 2004, 01:59 AM

Heat pumps are terrible. They are for smooth talking salesman to make a quick buck and only work in places like Floriday and Texas.

Virginia doesn't get that cold so if your electric bill is low enough in the winter, just live with it. I would prefer solar heat over a heat pump but you have to take what you have or spend lots of money.

dday · November 14th, 2004, 02:13 AM

Thud, get a meter and ohm out the fan motor windings. Sounds like the condensor fan motor is gone, or possibly the run capacitor is shot.