Heat Pumps

paintr56

Any experience with heat pumps or geo thermal heat pumps? I am looking to build a new home and have been thinking for a long time that one of these two heat sources would be the way to go. The only thing holding me back is they just have not really caught on and I am concerned I am missing the reason why. Any first hand info would be a big help. Thank you


Jim Bunton

HVAC Doc

I am unsure as to what you mean by heat pumps have not "caught on". Depending on your location/region, you can find at times more air to air heat pumps than gas furnaces/oil furnaces. As for Geo-Thermal heat pumps, the main draw back is the high initial cost. If you don't plan on being in your home over 10 yrs., you will not see the payback. On the plus side, they are EXTREMELY efficient as I have seen some total (everything in the house) electric bills for 3500+ sq. ft. homes only be $150/mnth. As I mentioned before, the draw back can be the installation cost which can start easily at $20K and go up from there depending on the loop system or well set up.

mdshunk

In my area (just north of the Mason-Dixon line), a heat pump is the normal heating and cooling system installed in new homes. The backup heat can either be the regular electric resistance heat package or a gas or oil furnace. For higher end homes (350K and up), they generally do it with a geothermal heat pump to avoid the ugly condensing units sitting outside the home.

NickTech

check to see what the cheapest fuel source is in you area. in my area its natural gas, second is oil, and last is electric heat(barring coal and wood). electric heat has always been the most expensive to use. as for a heat pump, they are only as good as the area they are installed in. meaning they are fantastic in arizona, or florida but not so good in new york or new jersey. they will always heat the building up to the right temp but that due to the back up electric heat kicking in. it is running on the same cost basis as your A/C. do you want an A/C bill all year round? a standard acceptable fuel bill is about $600 a season( a season being from nov to mar 5-6 mos). if your a/c - h/p is drawing $175 a month then you are looking at a seasonal heating bill of almost twice that. also, dont confuse efficiency with fuel cost per btu output.
heatpumps are designed for areas where the outdoor ambient temp is about 40 degr. at best. at this temp there is enough energy outside to pull in and heat up a home. once the temp gets lower than that then the electic backup heat kicks in. this is where you bills go up. geo thermal is a good method, but it may get pricy.

mdshunk

Nick, whatcha' mean?

Cost per BTU (or more normally, $$ per Therm) is the only way to compare 'apples to apples' heating costs, isn't it? Maybe I'm confused with what you meant.

HVAC Doc

A good way to compare "apples to apples" is to use these formulas to determine which will be your most cost effective solution:

http://www.thermopride.com/pdfs/fuelcostcomparison.pdf

This also allows you to play with costs and see what anticipated fuel costs might be in the future.

NickTech

100 cu' of nat gas yields 100,000 btus (1 therm) and might cost about $.90
1 gal of #2 fuel oil yields about 144,000 btus (1.4 therms) at about $2.50/gal
3413 btu's per kilowatt/hr. 29kwh = 1 therm @ $2.50

1 therm nat gas = $0.90
1 therm #2 oil = $1.70
1 therm of electricity = $2.50

apples to apples
you decide what you want to pay for heating your home.
efficiency is only how much of those btus are actually going into your home to heat it vs. how much go up the chimney for flue exaust. compare initial cost with seasonal efficiency to see what your pay back will be.

NickTech

that thermopride site is pretty cool, but the prices are way outdated.

HVAC Doc

Actually, you are supposed to enter the prices that are relevant for your geographical area. The prices listed there are for example only to show a person how to figure the formulas correctly.

NickTech

ooooooooh