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Old 11-21-2008, 08:55 AM   #1
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Heat pump or Gas furnace?


Which would you prefer for use in the Mid Atlantic around Philadelphia? Our gas heater needs to be replaced and our HVAC guy is suggesting going with a heat pump because they are cheaper to run than gas furnaces. The install cost is about a wash so which is the better option?

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Old 11-21-2008, 11:35 AM   #2
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Heat pump or Gas furnace?


I just replaced my heat pump with a Carrier Infinity heat pump and love it. It is in heat pump mode even in the low 30's and the air from the supply vents is warm. The variable rate is great in the summer to dehumidify effectively.

I had the option to convert to gas and am glad I didn't. If it gets really cold for extended periods of time there, you could get a heat pump with a gas furnace back-up. Shop around a lot first.

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Old 11-21-2008, 12:18 PM   #3
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Heat pump or Gas furnace?


I just met with HVAC company #2. Didn't recommend the heat pump because of the size of my house (1600 sq ft). He said my furnace is 23 years old...wow...thought it was younger.
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Old 11-21-2008, 01:00 PM   #4
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Heat pump or Gas furnace?


Quote:
Originally Posted by gone_fishing View Post
I just met with HVAC company #2. Didn't recommend the heat pump because of the size of my house (1600 sq ft). He said my furnace is 23 years old...wow...thought it was younger.
Don't use this guy. Size of your house has nothing to do with adequacy of a heat pump, unless he meant something else. Your house is a little on the small size by todays standards, and folks with much more sq ft have heat pumps.

An HP can work in your area, but you will need backup/auxilliary heat. What was recommended there?

To get a better sense of what will give you the lowest operational cost, please post your NG and KWH rates including taxes. I can then post some scenarios.
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Old 11-21-2008, 01:52 PM   #5
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Heat pump or Gas furnace?


Doesn't really matter if your house is 800 sq ft or 4000 sq ft as far as if a heat pump is a good choice or not.

You may wish to check to see what your electric company rates are going to in 2010.
Thats when the deregulation will take effect.
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Old 11-22-2008, 02:28 AM   #6
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Heat pump or Gas furnace?


Gone fishing.... I don't think the size of your house has anything to do with whether or not you use a heat pump or gas. I just had a new heat pump system installed at my home last month, sq. footage right around 2900. I had old carrier heat pumps and I was never really happy with their performance in the winter, but I just replaced them with some high effeciency Air Ease ( division of Lennox ) units and so far they work great. Tonight for example it's around 32 degrees, the stat is set at 70 and it's maintaining ( with the help of aux. heat ). I have heard that the colder it gets, the less efficient heat pumps become, but living down here in the south, that's not a major concern... I was surprised you said the price between an h.p. and a gas furnace was about the same because down here the heat pumps are considerably more, but since I don't have gas, well there you go. Good Luck.

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Old 11-22-2008, 10:38 PM   #7
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Heat pump or Gas furnace?


His point was that the savings during the winter months from the electrical company's discount wouldn't make it worthwhile to make the switch.
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Old 11-23-2008, 05:35 AM   #8
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Heat pump or Gas furnace?


Quote:
Originally Posted by gone_fishing View Post
His point was that the savings during the winter months from the electrical company's discount wouldn't make it worthwhile to make the switch.

Can you post what your gas rate is.
And what your winter electric rate is, all taxes and fee's included.

Just as an example.
NG at 1.81 a therm, is $19.05 for 1,000,000 BTUs of heat delivered to the occupied area, at 95% efficiency.
A heat pump at a COP of 3, and electric at 12 cents per KW is $11.72 for the same amount of heat.
At a winter electric rate of 9 cents per KWH, it would be $8.79 for that same 1,000,000 BTUs.
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Old 11-23-2008, 07:40 AM   #9
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Heat pump or Gas furnace?


beenthere is correct. You are looking for lowest BTU cost. We need to know what your utility rates are and what efficiency furnace you are considering. We can then give you a firmer answer.
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Old 11-23-2008, 08:04 AM   #10
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Heat pump or Gas furnace?


Just remember the most important step here is proper sizing. If either are oversized they will both cost more to operate than need be.
The cost annaylasis programs are only accurate if the unit is properly sized.
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Old 11-24-2008, 01:59 PM   #11
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Heat pump or Gas furnace?


I am not sure if I am posting the correct numbers but here is my last bill:

Gas: 23 CFM $43.72 total. $1.18623 is the natural gas charge. The rest is Distribution, balancing service, gas cost adjustment, state tax.
Electrical: 505 kWH @$.06590 = $33.28. Total after fees/taxes $79.48.

Average Ccf per month: 54
Average kWh per month: 645

My contractor came back with the following quote:
"Install new gas heating system using 95% efficiency variable speed heater, matching evap coil, 16 seer condenser, refrigerant piping, condenser pad, electronic thermostat, PVC venting. $8130 plus $850 for chimney liner."

"Same job as described above except instead of gas convert to 16 seer variable heat pump system. $6500 plus $850 for chimney liner.

Thoughts?
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Old 11-24-2008, 03:08 PM   #12
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Heat pump or Gas furnace?


To get your total cost just take total bill and divide by therms, CCF or KWH.

Cost per therm/ccf $43.72/23 = $1.90

Cost per KWH $79.48/505 = $.157

Compare the cost of 1 million btu's of heat.

Gas furnace with gas at $1.90 per therm, 95% efficient furnace:
(1,000,000 / 103,000 btu per therm) x 1.90 / .95
= $19.41

16 SEER 3 Ton Goodman Heat pump with electricity at 15.7 cents per KWH , C.O.P. = 3.5 at 35F:
(1,000,000 / 3414 btu per KHW) x .157 / 3.5
= $13.13

All HP's performance changes as outdoor air (COP its called) and so cost changes also.
At some point your HP will become equal in cost as your furnace (economic balance point), so you might as well use the furnace at that point. With these assumptions that COP gets hit around 10F.
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Old 11-24-2008, 03:23 PM   #13
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Heat pump or Gas furnace?


I was just told that the first 600kWh is normal rate and the rest is 50% from Oct to March.
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Old 11-24-2008, 03:36 PM   #14
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Heat pump or Gas furnace?


Don't assume you'll have a COP of 3.5 as an average.
Only certain HP's in certain sizes will have that.


Sounds like your on PECO.

Find out what your rate will be if you have a HP installed.
They have discounts for HP's.
Part of your gas bill may also be the monthly fee you pay, weather you use any gas or not.
So in the cost comparison, that fee is not included, since your already paying it.
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Old 11-24-2008, 03:44 PM   #15
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Heat pump or Gas furnace?


Quote:
Originally Posted by gone_fishing View Post
I was just told that the first 600kWh is normal rate and the rest is 50% from Oct to March.
That will make a difference in your heating bill with a HP.

If your looking for comfort, and eonomy, a dual fuel will save you 100 bucks plus, per year on heating compared to a HP only.
Or, over 300 bucks a year compared to a gas only heating system.

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