Opinions wanted on dual fuel heat pumps

[higgins]

I'm considering a dual fuel hybrid heat pump system, with propane being the gas fuel. I'd like to hear from people who have lived with them one through an annual cycle or three.

I like the idea of not being tied to one fuel through heating season, particularly with the volatility of propane prices. I would have the comfort of gas heat during colder periods and the efficiency of a heat pump when it's only moderately cold.

I like the idea of having backup electric heat if the gas system malfunctions.

I live in the upper southeast so a heat pump will suffice much of the time, but we do have the occasional cold spell. It's already been in the upper teens several nights this season. Thanks for your help.

[Superfly]

Are you talking the hrdronic in floor hear using propane and electric boilers ?????

My bud has both in his house he uses more propane as it is cheaper in the long run and he works for the electric Company.

I have straight electric in my shop and if you have the heat up around 50 degrees it kills your check book.

[uscra112]

I'm no fan of heat pumps, unless you live where it never, ever gets below freezing. Any colder and they get very inefficient, and I once had charge of six industrial units on the roof of a 40,000 square foot building on Long Island that would ice up so bad in cold damp weather that we sometimes had to shut the plant down for a long weekend. How many hours I spent up on that roof thawing those bloody things out I don't wanna remember. It was like being on the deck of a carrier in the North Atlantic.

When I bought my current retirement hideaway, I looked at them again, but ye gods, the prices! I settled for wood, with electric cove radiant in the bedroom, bath and kitchen, which are pretty much the only rooms I use in the winter anyway. Does run up the electric bill, so I leave 'em off 98% of the time. And I'm on a co-op, so my rates aren't quite so onerous as they would be if I were getting my power from a for-profit utility corp. Not that that will last, the closing of coal plants by the OBama EPA is going to double the rate by 2016, they say.

Look into natural gas, if that's an option. The price of natgas is down to less than half of what it was 5-6 years ago, and with all the production that's gonna come on line from the Marcellus Shale in the next 2-3 years, it might go even lower. The main holdup now is infrastructure - processing/pumping stations, pipelines. They've started on one of those processing facilities 4 miles up the road from me. I reckon two years and it'll be on line.

[schutzen]

I use a water source heat pump, but my son uses a dual fuel unit. His brother-in-law is a heating and air tech. His advice to my son was get the dual fuel unit, the energy savings will offset the extra cost within three years. We live in the Ice Belt" and heat pumps are only efficient 9-10 months a year. The son keeps his set to switch from electric heat pump to gas furnace at 38-40 degrees F. He has been very happy with the unit and it's operating cost.

Do not forget that caulking and insulation will save you at least as much as a new heat/air unit will. Seal up all cracks, add extra insulation to the attic, place plastic on the ground in the crawl space (if you have one); in short anything you can due to reduce air exchange (inside to outside).

[06ackley]

Being in the hvac trade I personally like heat pumps.If propane is your fuel then I would definitely go with a heat pump.Yes they get inefficient if it gets too cold outside but if you are running it with an outdoor sensor and t-stat you can have the heat pump shut off on its own if it gets too cold.I don't like running heat pumps with a dual fuel kit.Being in the southeast you should be fine.You might also want to look at the geothermal systems.Very efficient and work really good.

[turmech]

When I think of a dual fuel heating system I generally think of a gas furnace with an heat pump coil located on top of the furnace connected to a heat pump outside unit. These set ups have to function so the gas furnace does not generally come on at the same time as the heat pump. This is because the gas furnaces output temp will actually overheat the heat pump if ran at the same time. This once made the installations somewhat difficult requiring a complex control to interlock the two systems (defrost cycle added to this but more than you need to know). Now we have thermostats which can handle the staging making it quite simple to control and can even incorporate out door temperature in the staging.

I suppose another type of hybrid system would be a heat pump fan/coil indoor unit, a heat pump outside unit, and a hot water coil in the duct work supplied by a oil/gas boiler. This type of system does not present the same staging issues as the hot water coil is upstream from the heat pump coil. This is opposite of the first system as the gas furnace has to be before the heat pump coil due to the coil would rust out the furnace during A/C mode. This system would allow for easier installation of electric back up heat as the fan/coil would have a location for it. The first system would require a duct mounted electric heat package. The duct mounted ones are a little pricey, non-stock, and difficult to find room to mount in a lot of installations.

I would have a load calculation of the home done and if the cooling load matches heating load I would personally just install a heat pump. Not to ruffle any feather but LP is hard to justify base on operating cost for a lot of homes. I personally like heat pump paired with a wood or pellet stove for feeling cozy on the extra cold nights.

[Three44s]

That last post resembles us at the end!

We have an electric furnace/heat pump. We added a big wood stove on a 2400 SqFt. energy efficient home in Dec. of '10 ...........

We are now happy campers! Warm and cozy!

But we have our own forest wood and the tools and equipment to take most of the fight out burning wood.

My wife and I really struggled with the decision on propane vs. wood.

We were up watching a forest fire near our family's forest land ...... I decided right there and then and my wife was spot on with that that we'd be absolutely crazy to not burn wood for as long as our bodies would allow to.

When the time comes, we'll take out our wood stove and put in a propane unit.

Power outages are not nail biters anymore either!

Best regards

Three 44s

[smoked turkey]

We have a heat pump here. Nothing fancy. Just the air to air unit. We have ceiling cable for a heat source when it is below freezing. But I do have a wood stove in the basement and I greatly prefer it over any other heat source. People accustomed to wood heat always say its the warmest heat they know of. I too feel that way. As long as my wood supply holds up that is what I like.

[Taylor]

When it does get below 30,our house will never get above 60.I like the duel fuel idea.

[Lloyd Smale]

my dad was a furnace man most of his life. His advice to people up here where it gets real cold is to foget the heat pumps. For what one cost over the suplementle heat source you will need it would take the lifetime of the unit to recoup the cost if in fact you ever did. If your living in an area that rarely sees temps below 30 and need air more then heat there a good deal but for most in the colder areas buy the best high effiecientcy gas furnace you can afford.

[376Steyr]

My first choice would be natural gas heat/electric cool, with no heat pump. If natural gas isn't available, a heat pump with an auxilary propane furnace is a good way to go. As the above posters said, run the heat pump until it gets down to 30 or so, then switch to propane. Get the biggest propane tank you can fit on your lot (fire code limits the sizes based on distance to house and property line) and fill it when prices are lower.