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captain planet
07-23-2012, 03:13 PM
First things first, our house is an all electric home build in the late 70's. Furnace is original.

THE PLAN
Convert the house over to natural gas and put in a new hot water tank this summer. In a year or two put in new gas furnace with central A/C and then replace the new electric dryer and range as they fail with gas units.

THE REALITY
The heat pump went out mid week last week and it makes no sense to replace the heat pump on a 35+ year old furnace. So, the gas conversion/furnace replacement has been given a swift kick in the rear. Oddly enough I installed the interior gas line this weekend which was scheduled about 6 weeks ago.

THE QUESTION
The opportunity doesn't come along very often (thankfully) to be able to put in a new heating/cooling system. So, I'm looking at the most energy efficient options. My considerations are putting in a conventional 96%+ efficient gas furnace with central A/C unit. The other option we are considering is putting in a "hybrid" system, which is a gas furnace with heat pump. The way this works is, the heat pump heats the house until the outside temp gets down to around 30 to 32 degrees, after that the gas furnace takes over. These systems can also be changed around to heat with gas at varying temperatures over 30 to 32 degrees depending on the cost of utilities to get the best/lowest heating costs.

Does anybody have one of these systems that can shed light on how much savings in heating costs they have seen with these systems? This is obviously a money decision so I have to weigh whether or not the up front cost is worth the savings seen on the back end. We are planning on being in this house for a while (greater than 10-15 years) so time to recover the up front costs there.

Thanks in advance for any advice you can share with me.

blakehardesty
07-24-2012, 08:00 AM
I have no natural gas to my house. In the early ninetys they put in city water and sewer around the lake. When I bought my house i had a crappy a/c with baseboard heat. Well, long story short, I ripped that out, used my old well and threw in a geothermal unit for a little under $4,000. I pull my water from the well and it dumps right back into the lake. Since then I have converted the business to geo and my dad converted his house. My highest electric bill since I did this three years ago............. $190. I live in Indiana where it gets hot in the summer and cold in the winter.

captain planet
07-24-2012, 08:32 AM
I never considered geothermal. My house was well and septic when built. Sometime in the early 90's water and sewer came through and the well is still there. I'll have to look into that option as well. Thanks.

jkski
07-24-2012, 08:44 AM
I never considered geothermal. My house was well and septic when built. Sometime in the early 90's water and sewer came through and the well is still there. I'll have to look into that option as well. Thanks.

A word of caution...this may be dependent upon the county in which you live but, in my area, when they brought city water through, if you chose to hook-up you had to abandon your well and fill the casing with cement. I hooked-up and simply left my outside faucets still hooked to the well, as they were completely independent lines figuring I was fine and then the county came knocking about 3-4 years later to inspect. Long story short, I played dumb but they did make me abandon my well even though I argued for it as it posed no threat to the city water. They stated that if I wanted to keep my well I would have to install a backflow preventer at a cost of roughly $200-$300 plus I would be subject to yearly inspections that carried a fee of $50 or something stupid like that. I asked what the backflow preventer would do as the water lines within my home were independent of each other and there was no way that well water was going to get into the city water lines but they were not interested.

My point.....if you are thinking of using your well for geo just make sure that they are not going to come by a few or two from now and tell you to abandon it.

JohnE
07-24-2012, 09:06 AM
You will need 20 - 30 gallons per minute from the well to go with a geo system. My choice would be the high efficiency gas system. The new heat pumps are worlds better than the older ones, but I wouldn't bother going with the hybrid. If I were building now (and I hope to within a year) I'd be going high efficiency gas furnace and tankless water heater. (Rinnai)

AFX-15
07-24-2012, 09:17 AM
I installed a hybrid system in my house exactly what you are talking about. Back story.

I have a 2800sf 1925 4 square colonial and when I bought the house it had a forced air gas furnace that was 30 years old at least... cost me $600 a month to keep the house at 65 degrees in the winter months ( I live in SW VA). I put in two carrier systems. In the lower level its a 98% efficiency gas furnace with a 17 Seer heat pump/AC. I set the switch over temp at 40 degrees because after using the system for a few weeks, the heat pump would just run and run from temps 32- 40 degrees.
The savings: I keep my house in the winter at 74 and it costs me around $80 a month.

Additionally, I put a standard heat pump/AC unit in the attic for the upstairs (same SEER rating) and my electric bills despite having two units has reduced by half in the summer months.

AFX-15
07-24-2012, 09:18 AM
The two systems installed with extra duct work and moving the cold air return cost $13500. I would do it again and again. Best money I spent on this old house with no insulation in the walls. haha

JohnE
07-24-2012, 09:43 AM
I don't see the point in using a hybrid system. I don't see the cost of the electricity to run the heat pump compressor being less expensive to run than the gas to run the furnace. The reason to use a heat pump would be if gas were not available.

Granite_33
07-24-2012, 09:47 AM
I have no natural gas to my house. In the early ninetys they put in city water and sewer around the lake. When I bought my house i had a crappy a/c with baseboard heat. Well, long story short, I ripped that out, used my old well and threw in a geothermal unit for a little under $4,000. I pull my water from the well and it dumps right back into the lake. Since then I have converted the business to geo and my dad converted his house. My highest electric bill since I did this three years ago............. $190. I live in Indiana where it gets hot in the summer and cold in the winter.


Geothermal systems are great systems. Pump and dump systems are even better since the water is a consistent temperature

captain planet
07-24-2012, 10:04 AM
I don't see the point in using a hybrid system. I don't see the cost of the electricity to run the heat pump compressor being less expensive to run than the gas to run the furnace. The reason to use a heat pump would be if gas were not available.

I have been told that on a gas system when you put 1 BTU in (gas) you get back the efficiency of your furnace. For example, if you have a 96% efficient furnace when you put in 1 BTU of heat by gas, you get back .96 BTU in heat; 96%. Conversely, with electric heat it is 2 to 1. You put in 1 BTU of heat by electric, you get 2 BTU back in heat. The downfall is it is only good down to somewhere in the 30's.

JohnE
07-24-2012, 11:07 AM
I have been told that on a gas system when you put 1 BTU in (gas) you get back the efficiency of your furnace. For example, if you have a 96% efficient furnace when you put in 1 BTU of heat by gas, you get back .96 BTU in heat; 96%. Conversely, with electric heat it is 2 to 1. You put in 1 BTU of heat by electric, you get 2 BTU back in heat. The downfall is it is only good down to somewhere in the 30's.

Maybe, but when you say electricity you mean via heat pump. And the 2:1 is at maybe 50 degree temps, not colder. But what does 1 btu of gas cost vs. 1 btu of electricity? Looking at it in your example even electric resistance baseboard is 100% efficient and would be a better choice than gas. Which obviously isn't the case.

JohnE
07-24-2012, 11:09 AM
Many geothermal systems need electric back-up. I've wired a lot of them.

blakehardesty
07-24-2012, 11:12 AM
Many geothermal systems need electric back-up. I've wired a lot of them.

Mine has an electric backup built in.

AFX-15
07-24-2012, 11:23 AM
The benefit of the hybrid is that you are using the most efficient system depending on the temp and in cooler temps, gas is immediate heat at the cheapest cost. In my set up the downstairs gas furnace will heat the whole house in the winter.

JohnE
07-24-2012, 11:29 AM
The benefit of the hybrid is that you are using the most efficient system depending on the temp and in cooler temps, gas is immediate heat at the cheapest cost. In my set up the downstairs gas furnace will heat the whole house in the winter.

So you think that between 40 - 60 degrees the heat pump saves enough over gas to justify the added expense? Have you used a fuel calculator? I haven't, but I can't imagine any savings.

AFX-15
07-24-2012, 11:39 AM
JohnE.

I have an old house... using a fuel calculator would probably drive me crazy. I have had an energy audit done on the house and I took care of the basic things (replace windows,sealing drafts, insulating the attic). I wont lie, my system runs a fair amount, but it doesnt cost anywhere near what I was paying before. What I can simply say is that the hybrid system wasnt that much more expensive and the money it saves me, based on general estimates of both a traditional system and the old system, I know I am ahead.

Also, the hybrid system gives me the option to be a little more reliable in inclement weather if the electricity goes out in the winter with the small children I have.

2RLAKE
07-25-2012, 07:58 PM
i studied things 7 years when we built our new house ... 2x6 walls, high thermally efficiency windows/doors, all brick or natural stone, etc. I found several website that were very helpful ... you enter your zip code, house size, numbers windows, 2x4 or 2x6 etc and it helped you decided which direction to head. In my neighborhood we have propane which is much more expensive than NG for each BTU. I went all electric. My house is 2x bigger than my previous cookie cutter house yet my average bill, summer or winter is less

2RLAKE
07-25-2012, 08:03 PM
i would have gone with geothermal (we have 2.5 acres) but there were no tax incentives in my specific county (not trying to be a whiner) ... it was hard to amortize the extra $15k over the annual savings. In hindsight i wish i would have gone geothermal with a propane backup ... but we were running over budget anyway at the time

Now i just need a wind turbine and i'll be self sufficient!

JohnE
07-25-2012, 08:08 PM
JohnE.

I have an old house... using a fuel calculator would probably drive me crazy. I have had an energy audit done on the house and I took care of the basic things (replace windows,sealing drafts, insulating the attic). I wont lie, my system runs a fair amount, but it doesnt cost anywhere near what I was paying before. What I can simply say is that the hybrid system wasnt that much more expensive and the money it saves me, based on general estimates of both a traditional system and the old system, I know I am ahead.

Also, the hybrid system gives me the option to be a little more reliable in inclement weather if the electricity goes out in the winter with the small children I have.

I dont think there is much difference. I just don't think there is much if any savings with the heat pump. And there isn't a huge additional cost, either. To me, the reason to go HP is if gas isn't available. The only way to tell is with a calculator. Or compare one season to the next since you have both options.

akps190
07-25-2012, 08:59 PM
Where I live, HPs are not cost effective. However, they can be cost effective compared to gas, depending upon the cost of gas vs the cost of electricity. For example, where I live the cost of electricity is approximately 3 times more expensive than gas on a BTU to BTU basis. This is because our electricity is generated using gas, so there is obviously some expense in using gas to produce the electicity and distribute it. So, if the HP pump in the given environment can produce 2 BTU out for every 1 BTU in, then it would be an approximate wash if the cost of electricty is twice the cost of gas. You can look at your local utility rates and there are some convertor web sites that will compare apples and apples for gas vs electricity. Geothermal HPs are more efficient and can produce more BTU out vs BTU in, because they have a higher temperature heat sink (ground/water); but they also cost a lot more. My experience is that HPs are cost effective where electricity is low (hydro source) and gas or oil is high. 5 years ago, HPs were a hot commodity; but now gas prices are at a near historic low and no expectation to rise in the near future.

JimN
07-25-2012, 09:46 PM
First things first, our house is an all electric home build in the late 70's. Furnace is original.

THE PLAN
Convert the house over to natural gas and put in a new hot water tank this summer. In a year or two put in new gas furnace with central A/C and then replace the new electric dryer and range as they fail with gas units.

THE REALITY
The heat pump went out mid week last week and it makes no sense to replace the heat pump on a 35+ year old furnace. So, the gas conversion/furnace replacement has been given a swift kick in the rear. Oddly enough I installed the interior gas line this weekend which was scheduled about 6 weeks ago.

THE QUESTION
The opportunity doesn't come along very often (thankfully) to be able to put in a new heating/cooling system. So, I'm looking at the most energy efficient options. My considerations are putting in a conventional 96%+ efficient gas furnace with central A/C unit. The other option we are considering is putting in a "hybrid" system, which is a gas furnace with heat pump. The way this works is, the heat pump heats the house until the outside temp gets down to around 30 to 32 degrees, after that the gas furnace takes over. These systems can also be changed around to heat with gas at varying temperatures over 30 to 32 degrees depending on the cost of utilities to get the best/lowest heating costs.

Does anybody have one of these systems that can shed light on how much savings in heating costs they have seen with these systems? This is obviously a money decision so I have to weigh whether or not the up front cost is worth the savings seen on the back end. We are planning on being in this house for a while (greater than 10-15 years) so time to recover the up front costs there.

Thanks in advance for any advice you can share with me.

I bought two furnaces (gas) from www.alpinehomeair.com and haev been very happy with them. Two-stage blower, not super high efficiency (house isn't terribly large) and they have distribution locations all around the country. I don't think it took more than a couple of days to get here, either time. They're Goodman and, while most of the HVAC contractors I called about installation dumped all over them, none of what they mentioned as bad aspects is true. They also double the manufacturer's warranty on the heat exchanger, from ten years to 20. Great service and they have people on hand to help with tech questions and design.

JimN
07-25-2012, 09:47 PM
Many geothermal systems need electric back-up. I've wired a lot of them.

Do you do any solar power installations? PM me, if you get a chance.