Seeking Information About Dual-Fuel Heat Pump Systems

Marp2 · ‎01-31-2012

I need to replace my AC system and within the next day or two I have to make a decision about whether to go with a straight cool AC and continue using my propane fueled furnace for heat or to get a dual-fuel hybrid system.

Since I don't know anyone with a hybrid system I'm hoping to find input on the pros and cons from any here that may have or knows about these units.

kittymomNC · ‎08-09-2012

If you're talking about a combination heat pump and propane hybrid, my son put one in when he bought a house about 3-1/2 years ago because natural gas is not available to him yet. It has worked well - it heats with electricity most of the time, but when the outside temp drops down to a set temperature, it turns on the propane part. If it had to heat solely with electricity when it gets really cold, it would be difficult since a heat pump doesn't actually produce real heat like a gas furnace - somehow it takes heat out of the outside air (don't know yet how it does this when it's cold!)

Where we are, we don't have really cold weather too much of the time, although we do have it down in the 20's and below-even down to the low single digits at times. He filled his 300 gallon propane tank when he got the unit installed, and has only added 100 gallons one time since then. He moved in in June of 2010, so he's been through 4 winters. What you decide might depend on where you live, if you're in a colder area where the propane would kick in more often. And the price of propane has been pretty high in our area. If this isn't what you're talking about, I'm not familiar with any other hybrid units. Hope this helps.

I just realized you're in western NC - we're in central NC in the Piedmont, so you do get more colder weather than we do probably. But at least you're not someplace like Michigan where it seems to be really cold and snowy all winter!

RedTop · ‎09-01-2010

While I don't know any specifics about dual-fueled hybrid heating systems, I feel sure there are energy savings involved. I would guess the original expense for this type of heating system would be substantial, but would pay off in yearly savings.

Personally, if I were building a new home, I would likely consider a dual-fueled hybrid heating system option. If I were retiring soon and needed to upgrade my heating system before I quit work, I would probably consider this option. However, if my propane fueled furnace was relatively new and working well, and my propane source was secure, I would choose to keep my current heat system, and just add a heat pump for the air conditioning feature. For me, overall cost, and the efficiency factor for my home would play a strong role in my decision. If your home is older, is there anything else that has to be done for this hybrid conversion? Wishing you well with finding out what you need to know before making your decision!

scotttie · ‎03-09-2010

We have an LP bottled gas and heat pump. I think it tends to use a lot of electricity, other than that, i don't have any info.

kittymomNC · ‎08-09-2012

Red Top's post just made me think about the cost -the original unit was all propane and outside the house (like a "gaspack" unit for natural gas). This one is about the same size unit and installed on the same concrete slab. It was put in by a local company my family has used for years, and they said the cost was not much more than a natural gas unit would have been if that option were available to him. It might also depend on the size of your home. I know that propane goes up and down in price, and lately it has been pretty expensive, so he felt this was his best option until and if they run natural gas out a little further.

Marp2 · ‎01-31-2012

Thank y'all for your replies. They have helped give me direction and clarity.

Kittymom,

I've educated myself as much as possible on how the system operates and my two biggest hesitations at this point is the max heat it appears the heat pump throws out (about 105 degrees compared to about 135 degrees by the gas furnace) which with milder outside temperatures will not be an issue for taking the chill off and how much it will increase my electric bill versus how much it will save in propane.

We do get colder than the piedmont but I'm below 3500 feet so it isn't usually bitter cold (last winter excepted).

RedTop,

From my research it seems the increased cost of this type system is between $600-1,000. That is if my existing furnace is compatible which is questionable. If I don't have to replace the furnace to get the most benefit from a hybrid the cost difference will only be a consideration not a definitive factor. If I'm told I need to replace the furnace I hope there is a package deal. The more I learn about the hybrid system the more I like the idea.

DoubleDog2 · ‎03-09-2010

About 30 years ago we put in a heat pump/ac unit which is outside, and an LP furnace that is in the attic, and have been very happy with it.

The heat pump works great until the temps get down to around 32 degrees, after that it is not very efficient at all and the LP furnace automatically kicks in. We had to replace the outside heat pump about 6 years ago but the furnace is still doing great.

In some areas you may be able to get a break on the equipment or financing through your electric company. Also, I think you may get a rebate on your taxes for installing energy saving equipment. Unless that program is over by now.

Marp2 · ‎01-31-2012

Thanks DoubleDog. Do you find that in the winter the heat pump uses a lot of electricity? From some articles I've read I get the impression that as long as the heat pump is generating heat it uses less power than when cooling but that conclusion is only supposition. Do you find that or is the electric usage about the same as when cooling?

DoubleDog2 · ‎03-09-2010

On 5/12/2014 Marp2 said:
Thanks DoubleDog. Do you find that in the winter the heat pump uses a lot of electricity? From some articles I've read I get the impression that as long as the heat pump is generating heat it uses less power than when cooling but that conclusion is only supposition. Do you find that or is the electric usage about the same as when cooling?

The way I understand it there is no difference in the amount of electricity used in cooling vs heating and I have not noticed any difference in our bill. The heat pump does not manufacture heat, it has no heating coils or anything, it just transfers heat from one side to another. When it is in cooling mode it takes the heat out of the house. When it is heating it just reverses that process and takes heat from the outside. It's all done with condensers.

Sorry, I'm not good at explaining it. Some around here (I live in the country) have installed ground source heat pumps. They cost more but you probably won't need a furnace or LP gas because the ground stays at a constant 55 degrees, that makes the heat pump efficient no matter the weather. There are also some that have large, deep ponds and use them as a source for the heat pump.

Hope this helps... Lynn

Marp2 · ‎01-31-2012

DoubleDog said, "The way I understand it there is no difference in the amount of electricity used in cooling vs heating and I have not noticed any difference in our bill."

I think that answers one of my primary concerns, the cost of electric. It is the compressor running that uses the most power and while my summer electric bills are high they are not outrageous (compared to where I used to live) but my winter electric bills fall by about 55% once the air is off and the heat is on.

So much to think about and evaluate, so little time.