Duel fuel Hybrid heatpump?

[Mb190e]

We're on our second month of living with the new solar array 8.1kW. After further reduction in use and buying a system slightly oversize for our current use of 6.5kW. We are looking to use our excess electricity production. Looking for thoughts and opinions on dual fuel Hybrid heatpump with the propane hot air furnace. We currently use the propane hot air furnace and about 800 gallons of propane a year. I'm estimating we could have an excess of 4000 kWh's to use. And possibly cut our propane use in half???? Thoughts?

[Willy T]

I have 8.2 kw of grid tie, I bank all my excess production. I installed a duel fuel HP last spring and went into the winter with 2,800 kwh banked. The thermostat has a balance point for heating usually around 30° F, that is the point that it will switch to gas. I played with it by lowering it down as low as 10°F. at that setting I was burning off more electric than I wanted and settled on 15°F. I used a total of $79.00 of gas for heating and hot water last winter and still had 300 kwh at the end of February.

I went a step farther and added a hydronic water coil ( 12" x 12" ) in the furnace plenum that circulates hot water from the hot water heater. It has a outdoor thermostat that will allow it to run when the outdoor temperature drops below 28°F. It has a second thermostat that controls a small circulator pump that will come on with the HP and cuts on when the output air is below 95°F, maybe 5 minutes per cycle. It's a small assist, but makes a huge difference with the air temperature when the HP cycles. It takes about 10 minutes for a HP to get up to a reasonable temperature where to air doesn't feel cold. I have no kids at home and have the hot water heater set at 130°F. I have about $300 or so in it. A HP only has about 50% of it's rated output at 17°F.

Added: This was my second year, I used space heaters the first year to burn off the excess. While it worked, it wasn't very efficient. I like it to be 72°F, I tried a couple degree set back at night, I really didn't think it saved much, seemed like it had to run a long time to get back up to temperature in the morning. I got a 2 1/2 ton , but I needed that much for summer. I really think the heat cycles are more than they should be.

There is one logic issue I have not been able to solve. When the defrost cycle is engaged it will switch to gas. The problem is that a high efficiency furnace has a draft blower that runs a preset time before the gas ignites, during that delay you have colder air for about a minute. Not that big a deal, but it bugs me I can't solve it easily. I have thought about a delay timer on the reversing valve and I may try that this year. My hot water helps, but still have 60°F air during that minute.

[bcroe]

We're on our second month of living with the new solar array 8.1kW. After further reduction in use and buying a system slightly oversize for our current use of 6.5kW. We are looking to use our excess electricity production. Looking for thoughts and opinions on dual fuel Hybrid heatpump with the propane hot air furnace. We currently use the propane hot air furnace and about 800 gallons of propane a year. I'm estimating we could have an excess of 4000 kWh's to use. And possibly cut our propane use in half???? Thoughts?

You have the surplus on a grid tie? 27 KWH approximately equals 1 gallon of propane,
if your furnace is near 100% efficient. That is what happens here. A reserve of 4000 KWH
will replace about 150 gallons of propane in resistance heating. A heat pump will boost the
amount of heat generated many times. Bruce Roe

[russ]

You have the surplus on a grid tie? 27 KWH approximately equals 1 gallon of propane,
if your furnace is near 100% efficient. That is what happens here. A reserve of 4000 KWH
will replace about 150 gallons of propane in resistance heating. A heat pump will boost the
amount of heat generated many times. Bruce Roe

Actually it is better than that depending on the COP of the heat pump - probably 2.5 to 3 times should be.

[Mb190e]

Yes our system is grid tie. So my hopes of offsetting half of our propane is not out of the question? By the calculations above kilowatt hours versus gallon of propane and the heat pump being 2 1/2 to 3 times. I should be able to save 400 gallons of propane? Sweet! Okay next question we currently have central air 92% efficient furnace. house is 2300 square-foot and 3-1/2 years old. any idea what a heatpump is going to cost? I haven't been able to find any prices on the Internet for the Units.

Willy T what part of the country are you in? I'm in upstate New York

[Willy T]

Yes our system is grid tie. So my hopes of offsetting half of our propane is not out of the question? By the calculations above kilowatt hours versus gallon of propane and the heat pump being 2 1/2 to 3 times. I should be able to save 400 gallons of propane? Sweet! Okay next question we currently have central air 92% efficient furnace. house is 2300 square-foot and 3-1/2 years old. any idea what a heatpump is going to cost? I haven't been able to find any prices on the Internet for the Units.

Cost is location, location, location. Mine was $4,300 and I used same furnace for a Trane XR 15 HP. They had to remove the old furnace and reinstall with some new duct work because their coil box was bigger.

I am in Kentucky. get some bids. You have to find someone that is hungry. Time is on your side right now, so you can play hardball. Make a offer on a bid and let them do it when business is slow.

[russ]

The name is interesting - suppliers playing with words to confuse. They are a heat pump integrated into a forced air system. No dual fuel involved.

[Mb190e]

The name is interesting - suppliers playing with words to confuse. They are a heat pump integrated into a forced air system. No dual fuel involved.

Yeah I agree, I understand how they work and are integrated with the hot air furnace. when researching it seems like a lot of companies are now calling them dual fuel heat pumps. But now that I got rid of my electric bill and propane prices hitting $3.20 a gallon here last winter. I figured with the $3-$4000 investment in the heat pump. I think I should have a payback of about 3 years. I need to stay above 400 gallons of use on propane otherwise it's diminishing return. It will cost the same to buy 200 gallons that it does to buy 400.

[Willy T]

Yeah I agree, I understand how they work and are integrated with the hot air furnace. when researching it seems like a lot of companies are now calling them dual fuel heat pumps. But now that I got rid of my electric bill and propane prices hitting $3.20 a gallon here last winter. I figured with the $3-$4000 investment in the heat pump. I think I should have a payback of about 3 years. I need to stay above 400 gallons of use on propane otherwise it's diminishing return. It will cost the same to buy 200 gallons that it does to buy 400.

Where you really save is on both ends Fall / Spring, in the dead of winter maybe not so much in your location. 3 years is a short payback window, I thought more like 10-15 year life and divided by 2, so If I get 5-7 years payback I'll be happy. I could have saved $500 on a off brand HP, but decided on a name brand because of better service. Also My POCO will not buy any power, they'll only bank it on net meter.

[russ]

Yeah I agree, I understand how they work and are integrated with the hot air furnace. when researching it seems like a lot of companies are now calling them dual fuel heat pumps. But now that I got rid of my electric bill and propane prices hitting $3.20 a gallon here last winter. I figured with the $3-$4000 investment in the heat pump. I think I should have a payback of about 3 years. I need to stay above 400 gallons of use on propane otherwise it's diminishing return. It will cost the same to buy 200 gallons that it does to buy 400.

As long as the cost of propane is high it is a good deal and it really does not seem that propane will get cheap in the future.

[bcroe]

Yeah I agree, I understand how they work and are integrated with the hot air furnace. when researching it seems like a lot of companies are now calling them dual fuel heat pumps. But now that I got rid of my electric bill and propane prices hitting $3.20 a gallon here last winter. I figured with the $3-$4000 investment in the heat pump. I think I should have a payback of about 3 years. I need to stay above 400 gallons of use on propane otherwise it's diminishing return. It will cost the same to buy 200 gallons that it does to buy 400.

Past winter I had a tank full of $1.49 propane, but got a letter in Feb that the price
would now be over $5. I managed to stretch the cheap propane in my tank till June
at $1.59. Not having a summer reserve the 1st year, I also used $70 of electric heat
to avoid a $3000 propane fillup. I don't understand why 200 gallons should cost the
same as 400, its a matter of buying only in the summer here?

The original idea of payback here was kind of vague, but with this kind of energy cost
fluctuations, it may be sooner than I thought. Bruce Roe

[inetdog]

I don't understand why 200 gallons should cost the
same as 400, its a matter of buying only in the summer here?

The original idea of payback here was kind of vague, but with this kind of energy cost
fluctuations, it may be sooner than I thought. Bruce Roe

1. Supply and demand dictates that for a limited capacity supply chain the price of propane will be higher in the winter than in the summer.
2. Human nature leads to higher prices when you can get away with it because of great need.
3. With annual cycles factored out, propane prices are also just steadily trending upward along with other energy prices. (Except in Texas....)

[Mb190e]

Past winter I had a tank full of $1.49 propane, but got a letter in Feb that the price
would now be over $5. I managed to stretch the cheap propane in my tank till June
at $1.59. Not having a summer reserve the 1st year, I also used $70 of electric heat
to avoid a $3000 propane fillup. I don't understand why 200 gallons should cost the
same as 400, its a matter of buying only in the summer here?

The original idea of payback here was kind of vague, but with this kind of energy cost
fluctuations, it may be sooner than I thought. Bruce Roe

I'm in a propane Co-op. Tiered pricing based on use.

Spot price plus.

1 - 200 gal. + $2.05 per gal.
201 - 400 gal. + $1.20 per gal.
401 - 700 gal. + $ .65 per gal.
701 - 1500 gal. + $ .55 per gal.
1501 - 2999 gal. + $ .35 per gal.
3000 gal. +. + $ .35 per gal.


I'm also guessing if I could get my use down to around 400 gallons I could get my 500 gallon tank filled up once in the summer. Which I already do but then I get it filled up again sometime around Christmas or New Year's and then again and February or March

[DanS26]

I had a leased propane tank which I had to fill 2 to 3 times a year from the leased supplier. Needless to say I was at their mercy every time I had to fill.

Then I got smart, I replaced the leased 500 gal tank with two 1,000 gal tanks that I purchased. Yes the upfront cost was great, but I have already paid for the tanks in fuel savings alone by buying during the summer fill sales. I'm still burning $1.39/gal fuel and expect to buy a years worth of propane this summer in the $1.59 range.

Propane is a by product of natural gas production.....there should and is voluminous supply. The market IMHO is manipulated.

[parish8]

I doubt if this will work for the op but it might for someone thinking about this. I am running some lg mini splits. it worked well for me because I have a boiler and no central air or ducting. they are fairly cheap, quiet, easy to install for a diy person.

the numbers on these things are nuts. 26seer ac and when heating a cop of 3 at -13degf and cop of 4.7 at 47degf

even at -13deg they are cheaper for me to run than using natural gas. problem is the output falls off as it gets colder and at the same time the needed btu's go up. I just set my nat gas boiler stat a couple of deg lower than the minisplit stat and when they fall behind the boiler kicks in to catch things up.