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need expert advice in regards to dual fuel heat pump set up vs other options

need expert advice in regards to dual fuel heat pump set up vs other options


  #1  
Old 02-17-14, 07:03 PM
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need expert advice in regards to dual fuel heat pump set up vs other options

My house is about 30 years old, seems to be halfway decently insulated, about 1000 sq ft single level with unfinished basement in western pa. My current system is a heat pump with auxiliary electric heat. Now this winter has been really bad so it's not a very good example of average temperature s. However last year we used approximately 1800$ worth of electricity for the year. Keep in mind my house is all electric. No gas nothing.

Now I'm considering swapping out my air handler for a 40000 btu propane furnace and keeping the heat pump and auxiliary heat stripes as emergency heat if propane runs out unexpectedly.

My step dad is old school hvac guy so labor basically free. However I assume that it's going to cost about 1000$ for the furnace and gas lines and exhaust lines, misc parts breakers wire ect.
Which is cheap.

My concern is that from what I've researched online and from talking to other people that this furnace could potentially use 100 to 200 gallons a month. I'm guessing that I'd be on the low end of that. My uncle said he never uses more than a full 500 gallon tank (except for this year) and his house is almost twice what mine is. Either way to get started with the propane company @ roughly 2$ gallon (in spring) it's going to be 800$ plus tax and whatnot. So I'm beginning to wonder if it's even worth the gamble messing with a system that works ok. And I'd be spending an entire years energy bill on this project. Besides that I'll be paying on this year's electric budget until December. So all in all with paying for everything and paying current bill off I would anticipate possibly seeing a savings in 2-3 years and by then propane may go up and that could go up in flames. Man I'm really talking myself out of this.

After all the point of this is for saving money. The comfort level with my current system isn't fantastic but we're not freezing to death either. Does anyone have any experience with this? Can I expect to save money in the long haul?

I know the electric stripes are energy hogs but a bit of logic I have come up with is that since the heat pump in temps between 40 - 60s is so efficient that the lack of efficiency between 0-40 kindof even out? I could be completely wrong.

So should I even bother? Any opinions greatly appreciated and considered. Thanks
 
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Old 02-17-14, 08:20 PM
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If you can get away with less than 500 gallons per year in western PA, you are either very frugal or have a very well insulated house. A heat pump with a fossil fuel backup is a good system bukt using propane as the primary????
You need to do a manual J to determine the heat loss for your house, add some insulation, & tighten up the envelope.
 
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Old 02-17-14, 08:44 PM
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No I was going to keep everything functioning as it is now. Leaving the heat pump and use propane as auxiliary heat source and the heat stripes as emergency heat. Is this a good or bad idea? My house is pretty well insulated. We even have insulation in the floor between the basement and 1st floor. I know there is one major source of heat loss and I'm definitely going to square that away.

We actually have an addition that was built about 15 years ago and it's almost too well insulated. It gets so hot in our bedroom at night it wakes me up out of dead sleep sometimes.

If you're thinking that using less than 500 gallons a year is more or less a pipe dream then I might just as well scrap the whole plan bc at that point any hope to save a dollar is gone.

My uncle may indeed be frugal. Him and his wife quickly encroaching upon 60s and there kids are grown moved out ect. I have small children and me an the wife work opposite shifts so the temp in the house has to stay relatively steady. Besides that I hear heat pump works best that way anyways.
 
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Old 02-17-14, 08:56 PM
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Ok, I misunderstood. With a fossil fuel furnace, you would shut down the heat pump if the furnace came on via a fossil fuel kit. Unless you mount the HP coil on the furnace, ducting can be tricky.
 
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Old 02-17-14, 10:15 PM
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Propane in your area may be as expensive as electricity, particularly if you have to shut down the heatpump below 25-40F.

Find the cost per delivered kwh and gallon of propane in your area - based on both you can determine if it makes sense to get a furnace installed. (dual fuel controls alone may be $200-$500, don't count on $1000)

The heatpump portion of your system, provided that it's at least 12 seer/8hspf, is actually pretty efficient but doesn't have much capacity in cold weather. It would be a shame to shut it down as soon as it can't keep up unless burning propane will save you a significant amount of money.

The cost of repairs must be taken into consideration; a modern gas furnace has far more to go wrong than a air handler with heat strips. (a couple of $300+ repairs over 20 year lifespan isn't unusual)
 

Last edited by user 10; 02-17-14 at 10:31 PM.
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Old 02-17-14, 10:25 PM
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Alternative duel fuel setup:

There are high efficiency gas water heaters available which can be used for heating rather than just hot water.

You may be able to have the heat strips replaced with a hydronic coil, fed by a propane water heater which can also provide domestic hot water at a lower cost than electric. (known as "hydro air") Example: http://www.gsw-wh.com/downloads/PDF/GPDVENV0509.pdf

Basically the hydronic coil would function the same way as the heat strips do now.
 
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Old 02-18-14, 03:35 PM
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Ya I think I've pretty much scrapped the idea. I think money would be better spent adding more insulation. I think I'll spend a few hundred on that. I have a door that needs replaced which let's in some cold. I definitely like the idea of replacing the heat stripes with a hydro coil. I'll have to look into that. This is kindof a silly question but do they make a electric version of this?

My bottom line is that my electric bill is never going to go away and I guess it's not really that high all things considered. Adding propane system sounds good but if it's going to cost 1000 $ a year in propane then there's really no benefit. What I'd like to do is get a geothermal heat pump but I've heard it can cost 30k or so to pay for the install. I may be able to buy one and rent a machine to dig a huge hole but this is something that likely won't happen for some time.

Also considering possibly getting some kinda solar panels set up to supplement the electric bill. But that also is a big investment and will definitely take time to pay for itself.
 
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Old 02-20-14, 11:43 AM
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^Unless you've got a standard offer program (large subsidy for power produced by wind/solar) in your area, you'll be better off looking at solar hot water rather than photovoltaic (solar electric).

Indirectly, solar thermal would save far more electricity than a large photovoltaic array would ever produce.
 
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Old 02-20-14, 11:52 AM
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I definitely like the idea of replacing the heat stripes with a hydro coil. I'll have to look into that. This is kindof a silly question but do they make a electric version of this?

Read more: http://www.doityourself.com/forum/ga...#ixzz2ttDKPH6K
Yes, but it wouldn't save you any energy.

Electric is electric.

The idea is to get rid of the electric resistance heat without having to shut down the heatpump whenever supplemental heat is needed. A heatpump and furnace can't operate at the same time.

------------------------
What I'd like to do is get a geothermal heat pump but I've heard it can cost 30k or so to pay for the install.
Very pricey for sure - I wouldn't recommend geothermal.

There are air source heatpumps which are supposed to perform well in cold air for example -> Infinity 20 Heat Pump With Greenspeed - 25VNA0 | Carrier - Home Comfort

They have variable speed compressors which can compensate as the outdoor outdoor temperature drops.
 
 

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