Whole house A/C, heat pump or just A/C?

Hi,
I'm just about to bite the bullet and fit whole house A/C. I already have gas powered water filled radiators but since the cost of a heat pump is only $250 more than straight A/C I was thinking for spring/Fall heating (in DC) it might be a good idea. Never owned a heat pump but the sales guy claims they are just as efficient at making cold as regular A/C. Anyone wish to share the pros/cons?
Thanks
Nick..
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Find your cost per btu, for Ng electric. For me in the midwest electricity is 3x the cost of Ng. So electric will never pay for me. Post your Kwh and Ng costs with all taxes etc included. Radiators heat better - more evenly . You Sales Guy ? is a Sales guy, Is he BuBBA
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On Sat, 12 Feb 2005 18:08:16 -0600, snipped-for-privacy@webtv.net (m Ransley) wrote:

Nahh, Probably just some stupid uninformed dork wanna be trailer trash webtv idiot.........like you Ransley.
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m Ransley wrote:

Yes, but the heat pump has a COP (coefficient of performance) that may exceed 3, meaning the BTU of heat is a factor of 3 higher than the BTU of electricity put in. Thus there could be monetary savings even though electric costs more per BTU.
%mod%
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This is turtle.
Now speaking about Heat Pump verses the straight A/C system as cooling only. There is no difference between the two as efficient ability. They are rated in SEER .
Now Heat Pump verses the gas type hot water circulation systems. Here in Louisiana NO way use the Hot water circulation for we don't have winter. If you live in the Northern states AWWWW it is hard to figure but you will have to get with the locals and see what is right for your area.
TURTLE
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TURTLE wrote:

cost
for
cooling only.

rated in

in
winter. If you

have to get

I live in the Philadelphia area. When it gets much below 40 deg outside, I find the heat pump pretty useless.
When it gets below 32 outside, the heat pump coils can ice up and the defrost cycle pretty much negates any efficency savings the heat pump may buy you.
It is pretty good to take the chill off the house when its 45 or so outside. If thats worth $250 to you, then go for it.
Mark
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This is Turtle.
Here when they say we are going to have a hard freeze over nite they are talking about 25F or so. We have only about 3 or 5 days a year where back up heat on the heat pumps will have to kick in.
When you start talking about weather below 20F for week on end , well My thoughts on which system would work best would have to be just go Gas Hot air furnaces to keep up. Now here heat pump is fair to use but the state of Louisiana produces a lot of the Nature Gas supply of the 50 states and Natural Gas is fairly cheap here compaired to electric. Louisiana pipes a lot of Natural gas to the Ohio and Illinois area for their supply of gas. By the time the gas gets up there it cost about 35% higher than what it sells here for. This also changes too much for me to try to speak as which would be best up there.
TURTLE
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On Sat, 12 Feb 2005 23:40:44 GMT, Nick

If you compare SEER to SEER there is no difference in cooling efficiency. The heat pump is just an air conditioner that can be reversed to take heat out of the air instead of the opposite.
If you intend to keep your existing heat system, there may be no compelling reason to get a heat pump until you examine the costs of electricity and NG where you live. In our case, we heat and cool with the same unit. Called a gaspack. Electrical A/C combined with NG forced air heat. We have on order a dual-fuel heat pump which switches over to natural gas at about 38F. This gives us the best of both worlds. We can use electricity to heat until it is less efficient than NG, then it switches over. If I had a separate heat system as you do, I would have to do a completely different evaluation.
Dick
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Well if you regular heat went out on any given weekend in the next 20 years you could probably save the additional cost by turning on the heat pump and waiting until Monday to call out the repair person :-) Seems it would be worth the extra expense just for that reason alone.
Steve B.
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On Sun, 13 Feb 2005 08:43:45 -0700, Dick <LeadWinger> wrote:

Another thought too. In my home, I have oil fired baseboard hot water and replaced my conventional A/C with a heat pump this winter. Since the HP becomes my primary heating, I qualify for an electricity discount in my area (Philly region). The discount is such that after paying for the electricity for running the heat pump, my total electric bill is barely higher than it was without the heat pump but paying full electric rates. So in essence, I get very low cost heating for ~75% of my winter.
One additional piece of information - my heat pump is a geothermal unit. BUT it was installed in such a (crappy) manner that the efficiency of a good air source heat pump (>2.5) is better any time the temp is >~30 out. So if you do get electric discounts and your KWh usage is pretty high (my daily usage runs 60-120KWh), then you'll probably find your total utility bill to be very favorable when using a HP as much as possible when the temps are above freezing.
Here's an example. Numbers are based on my typical usage patterns when temps are in the mid 30's. non-discounted electric: $0.142/KWh discounted electric: $0.11/KWh daily usage before heat pump: 56KWh usage with HP, 6 hours/day: 80KWh electric cost, non-discounted: $239 HP cost, discounted: $264
actual cost to heat house using HP: $25.
If I were using oil as my primary heat, I'd still be paying the $239 for electricity then add on top of that the oil costs and electricity to run the circulators and burner. For me at current oil costs, this adds $100+/month under the above conditions (i.e. 30+ degree weather). So, roughly speaking, I would save $75/month during the winter.
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Interesting numbers. I also looked at those costs when making a decision on a dual-fuel heat pump vs our current gaspack. We have timed electrical service where we live. You have to apply for it. The meter measures power consumed during on-peak (9:00 A.M. to 9:00 P.M weekdays) and off-peak (week-day nights and week-ends.) The cost varies slightly between summer and winter, but right now we are paying $0.107/kwh on-peak, and $0.041/kwh off -peak. We try to shove as much useage into off-peak as we can. Hot-tub heating, dish washing and clothes washing are all done off-peak. We bring the house down to 65F at night in the summer, so we set the thermostat to start cooling down after 9:00 P.M. weekdays.
At the same time our natural gas runs as high as $1.14 per therm and continues to climb. Our heating cost in the winter can be as high as $200/month. By using the dual-fuel heat pump, I can heat the house with electricity down to about 38F. Anything below that will require natural gas. There is a large part of the year when our temperatures are above 38F, but we still need heat. Whereas now we use natural gas for all heating, I can limit it to those times we get below that. Also, with a SEER rating of 12.0 vs the 8.0 we have now, cooling costs will be significantly lower too. We should be getting our new system within the next 2 or 3 weeks.
Dick
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On Mon, 14 Feb 2005 08:48:55 -0700, Dick <LeadWinger> wrote:

I went over the electric costs again today and found that my numbers were in error. My providers have altered their rate plans quite a bit, so now, after the first 600kwh, my electric is $0.061/kwh (after the first 600kwh at normal rates) compared to $.125 non-discount. So the above numbers should be $210 and $185 discounted rate, making it $25 cheaper to heat the house with the heat pump than just the normal electric bill with no heat! The savings then increase to about $150/month below regular electric + oil heat.
Good luck on our new system. Let us know how it works out for you.
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On Sat, 12 Feb 2005 23:40:44 GMT, Nick

I went thru the same drill in VABCH last fall, after much research. Had 32 y.o. AC and oil-fired hot water baseboard. Installed heat pump. Although there are outside sensor/thermostat type gaqdgets that will do it for you, I simply watch the outside temperature. I set in my own mind a crossover point of 35 degrees. If I see the temperature is going to go and stay above that point, off goes the baseboard, on comes the heat pump. (Did that today after nite temps appear to have stabilized above 35 degrees at least until Thursday) Since I do not heat the house at night, if I want to hurry the warm-up in the morning, I may frun both systems until I get it where I want it, then secure the baseboard. Am gathering data now for comparison---whjich is mostly going to be a SWAG due heating considerations unique to my installation. And, I can't isolate those electrical expenses due only to the heat pump. Works for me. YMMV. If you want to discuss further, send me an email Roy
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Because there are advantages and disadvantages to both a heat pump and gas furnace based on the outdoor temperature, the dual-fuel solution really does give you the best of both worlds. It's the most comfortable heating system at any outdoor temperature, as well as one of the most efficient, versatile, and economical heating-and-cooling systems you can buy.
A dual-fuel heat pump is an electric heat pump and a gas furnace all in one. In the Tennessee Valley, where temperatures are typically above freezing and we enjoy some of the lowest electric rates in the U.S., a heat pump is the most efficient way to heat your home. In those few instances when the temperature drops below freezing, a gas furnace provides heat more economically. By combining the two, you can have the benefits of both systems.
On Sat, 12 Feb 2005 23:40:44 GMT, Nick

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Those are all good points....
Another factor to throw in is the wear and tear on the compressor. How often does the compressor need to be replaced and how much does that cost. You'd have to save a lot of oil to cover the $250 inital cost plus wear and tear on your A/C system.
There used to be a funny ad in Phoenix regarding heat pumps (yep we needed heat in Phoenix in the winter)
it's a pumpin in the sumer and it's a pumpin in the winter until it pumps its little guts out.
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The Trane dual-fuel heat pump we are buying has a 20-year warranty on the heat exchanger, and 10-years on everything else, including the compressor. Hopefully, it won't break right at 10-years. We do live in Arizona, but at 5,000 feet.
Dick
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