residential air-air heat pumps FAQ

We had our old oil furnace and old AC replaced with a Rheem heat pump in October. It has a ten year warranty and annual service cost will be $140. Do not know what weather is like where you live but we had many weeks of freezing this winter here in Delaware and it worked fine. I believe if it gets real cold there is additional electric heating. Electric bills were high but maybe half the cost of oil we would have needed. My wife is very happy with the cleanliness in replacing the old oil furnace.

Thanks for your reply. I'm in southwestern Ontario. The existing propane furnace can operate from my little Honda 5 kw generator during Jan. - Feb. power outages. I suspect that your heat pump's aux. electric heating would require something bigger ? John T.

My house came with the builder installed Trane. My climate is milder than yours, but it works well and trouble free in just over 5 years.

When switching from one mode to the other, it takes a few minutes for everything to switch.

My house is 1583 sq ft and the lowest temperature I've ever seen here is

You would probably need to keep the propane or some other heat source when the temperature gets below around 25 deg F. The aux heater in my heat pummp is 10 kw and I am in the middle of North Carolina. I have a wood stove for backup if the power is out which it seldom is for more than a day. Where you are it would probably take much more than 10 kw of aux heat and more than 5 kw to run the heat pump if the aux heat was not on. I would run the heat pump for heat to the temp gets below 25 or so deg F and even compair the electricity rate for the aux vers the propane for even lower temp.

John has the right idea - Propane when power is out. Not at all practical to run the heat pump on a generator - or aux electric heat. If John contacts me off-line I can give him the name of a local guy who is doing a fair number of heat pumps - a friend of mine

Not just aux electric heat. A furnace is a minor load. A heat pump is a much larger air conditioner. Check if you generator will start and run what you think about buying.

It is a problem that my generator cannot handle the heat pump as it did the oil furnace. We had a two day outage this winter and had it lasted longer we would have gone to a son's house. Along with fireplace I now have a couple of propane heaters for backup. We had considered a whole house generator but without natural gas service wife did not like the need for a large tank of propane for the generator. Whole house generator can use 2-4 gal. of propane an hour. My brother has had one for over a year and has yet to need it yet it costs about $300/yr to maintain.

We had to get rid of the oil furnace as it was aging and then we found the oil inlet to the basement tank had rusted through and there was water in the oil.

It all depends on how much you are willing to pay for the generator system . For me I can not afford to pay a large amount and our power is seldom out. I have a 3.5 kw gen that runs on propane or gasoline. I only run it on propane, but have a 5 kw older generator for the gasoline and to power for longer periods of time. With a heatpump I do not want to pay the cost to run it but have a wood stove in the basement for heat and while i would not use it a fire place in the main part of the house. If I just had a fire place I would install a wood stove insert or similar.

So there are two basic ways to go. Small generaor to get by and another source of heat or large generator with much cost.

For tose with many days below 25 deg F it will probably need a oil or propane heat for the cold days and the heat pump for the AC and days it is more efficent to use the heat pump instead of the gas or oil het.

My mother had a standby generator installed and she lives in Naples, FL. After the last hurricane which knocked out power for a couple weeks, the two old people living there wouldn't accept that anymore. She doesn't have a natural gas pipeline so a propane tank was installed underground. I think the generator is automatically tested every week or two so the propane truck has to come by every so often to fill it up.

Don't quote me on this, but I think the total cost for the generator, propane tank, installation was around $25,000 in affluent Naples prices. It's likely much less in other areas.

I seldom use the fireplace but have an insert that blows heated air from the grates. Actually have two fireplaces but closed one off as it had a sharp bend that could break. We had that problem with the oil furnace and had to line the chimney. Wife never liked me burning wood.

I always thought the testing of the propane generators was a big waste of fuel and money, but if they could afford a $ 25,000 system then money must not matter too much. I bought a dual fuel 3.5 kw and only ran it on propane. Ran it for about 15 minutes when I first got it about 4 years ago to see if it would run. Have only started it 3 times and it started right up each time. I would probably test that generator a month before hurricane season.

I guess that at my age and what I have in an IRA I might be tempted to do the same if I had power problems.

I hadn't given any thought to running the heat pump from my portable generator - A/C wouldn't be critical during a summer power outage. but it does raise a good theoretical question - if the modern heat pump technologies would possibly allow it ?