Heat Pump Question

[BParson03]

I am really interested in getting one of those hybrid systems, gas furnace with a heat pump. The only question I have is how effective would a heat pump be in my area? I'm in central Indiana, about an hour north of Indianapolis. I was just wondering how much of the time I would be able to use the heat pump before switching over to the gas furnace.

[Airmechanical]

look at the high and low temps for your area

if you have above 25 degree days for any significant amount of winter time, a heat pump would work well and save money



.

[havdaddy]

Your contractor will have that sort of information when he does his load calculation. It's in the book. They need those numbers in order to size the equipment properly.

[Kevin O'Neill]

Typically above 35 degrees outside, the heat pump is cheaper to operate than the gas. But that is in my area, with the utility rates we have here. In your area it can be different.

Talk to your contractor.

[tedkidd]

Hp also offers broader range because it will produce less heat during periods when less is required. Hybrid combo is really nice for reasons you wont understand until you live with it a while. This can mean much more even temperatures, more comfortable home.

[Joker]

Typically above 35 degrees outside, the heat pump is cheaper to operate than the gas. But that is in my area, with the utility rates we have here. In your area it can be different.

Talk to your contractor.

I have always heard people claiming HP's out perform gas(even in my area) but it must be a local thing because I have lived with gas,HP,Electric and gas under all weather condition beat HP hands down. It wasn't even close.

NG must be high in other parts of the country. The reason I say this because a standard 80% furnace beats any HP of any efficiency level in my area.

I have always believed it was the electric company pushing HP in place of NG units to push up profits!!!! LOL

[amd]

^That's irrelevant because no one knows how much you payed for electricity. Performance is a very vague term.

Heatpumps are more efficient (more heat relative to energy input) than furnaces but not necessarily cheaper to operate.

The terms: efficiency, capacity, and operating cost should never be used interchangeably.

[tedkidd]

NG must be high in other parts of the country. The reason I say this because a standard 80% furnace beats any HP of any efficiency level in my area.

I have always believed it was the electric company pushing HP in place of NG units to push up profits!!!! LOL

This is fairly simple math. If you want to know when and why you are wrong, post your electric and gas costs.

[beenthere]

I have always heard people claiming HP's out perform gas(even in my area) but it must be a local thing because I have lived with gas,HP,Electric and gas under all weather condition beat HP hands down. It wasn't even close.

NG must be high in other parts of the country. The reason I say this because a standard 80% furnace beats any HP of any efficiency level in my area.

I have always believed it was the electric company pushing HP in place of NG units to push up profits!!!! LOL


Post your electric and your gas rate. And did you use night set back with the heat pump.

[Kevin O'Neill]

I have always heard people claiming HP's out perform gas(even in my area) but it must be a local thing because I have lived with gas,HP,Electric and gas under all weather condition beat HP hands down. It wasn't even close.

NG must be high in other parts of the country. The reason I say this because a standard 80% furnace beats any HP of any efficiency level in my area.

I have always believed it was the electric company pushing HP in place of NG units to push up profits!!!! LOL

It depends on outdoor temperature. When it is very cold outside, the heat pump efficiency is low. When it is mild outside, the heat pump is very efficient.

A dual fuel heat pump has both a economic balance point and a performance balance point. They are different ever where you go. It depends on sizing, efficiency, climate and utility rates.

[Joker]

It depends on outdoor temperature. When it is very cold outside, the heat pump efficiency is low. When it is mild outside, the heat pump is very efficient.

A dual fuel heat pump has both a economic balance point and a performance balance point. They are different ever where you go. It depends on sizing, efficiency, climate and utility rates.

No argument. Being from Texas we are either hot or cold. LOL Most dual fuels in my area are turned to off and run straight gas or set to above 50degrees. Except for "old" people(who hate heatpumps) most people don't even turn on the heat until it hits in the low 40's. Probably because the ground is so warm?

Other areas people must have high NG and long mild temperatures which make Heat pumps valuable.

I think I would rather use the extra money that it would cost to purchase a heat pump and get a multi-stage 95% furnace.

Man it was another hot muggy day here, again. Dallas Texas is either hot as hell or cold. I think we run a/c 9 months 2 months of so so weather and a month of bitter cold. Each summer I think of moving north to a cooler place!!!!!!!!!!!!!! LOL

[Gimmered]

Joker I'd really like to see your delivered rates and the COP of your heat pump.

My heat pump was sized with heating in mind and doesn't switch to the gas backup until 5° and it is still cheaper to run then the 95% gas furnace.

[tedkidd]

Rates have been asked for 3 or 4 times. How often temps are mild in his area is tracked.

Some people prefer not to do the numbers, particularly when it's likely to prove them wrong.

[Joker]

This is fairly simple math. If you want to know when and why you are wrong, post your electric and gas costs.

12 cts a Kilowatt hour, NG I want to say $4.5 per MCF. Not real sure. Pay online and could not find a rate. Dallas/Fort Worth Texas.

80K 80% gas furnace 2.5 ton 13 seer a/c 4 ton blower.

This is my bills electric/gas since December.
Month----- TXU----Atmos
7-----------144----12
6-----------81------11
5-----------61------14
4-----------71------17
3-----------91------78
2-----------76------120
1-----------59------131

[tedkidd]

Cool, thanks. I'll run opcost on that this weekend when I'm at my computer, unless someone beats me to it. Some fudging is required to match cost. Generally you have to drop the equipment size a little to get the usage to true up.

Anyone else find that when you use actual size these programs tell you you spend double what the bill says?

Mcf - what's that in therms?

[beenthere]

Mcf - what's that in therms?

Should be 10 therms.

M would be 1,000. So 1,000 cubic foot.

[tedkidd]

45 cents per therm!? Including delivery? Electric include delivery?

[Airmechanical]

i have only lived in heat pump land for 5 years, but from what i have seen

it's cheaper to run a heat pump than a furnace at temps of around 25 degrees and above

if your system is undersized the above mentioned 25 degree number can be as high as 40 degrees

can one of you number crunchers come up with an actual "theoretical" number to make my semi-real numbers more accurate?

i am looking for some numbers like

how much a furnace costs to operate per hour at 30 degrees

then compare it to a heat pump at the same temp

then use different temps,



.

[BParson03]

Joker, I would double think that before saying you want to move to a colder place up north LOL. Our winters absolutely suck, and I am only in Indiana. I can't imagine what they are like even farther north than us.

[martyinlincoln]

Our gas rates are .90 for the first 20 therms and .69 after that. Electric is .08 a KW for the first 900 then .04 after that. Both have customer fees and taxes that amount to aprox $20 a month. No idea what my hp cop is but the ahri number for the system is 551617 if that helps. Actual temp where the hp can no longer maintain our house is 9 degrees. Economic balance point is?

[Airmechanical]

Our gas rates are .90 for the first 20 therms and .69 after that. Electric is .08 a KW for the first 900 then .04 after that. Both have customer fees and taxes that amount to aprox $20 a month. No idea what my hp cop is but the ahri number for the system is 551617 if that helps. Actual temp where the hp can no longer maintain our house is 9 degrees. Economic balance point is?

you have to figure as soon as the system requires auxillary heat, that's the point where the furnace gets cheaper to operate

so, heat pump plus auxillary heat equals more power usage cost than just a furnace

now to throw a bump in the road sometimes if it's not that cold, but cold enough to use the auxillary heater lets say for 5 minutes out of each hour use, at that point the heat pump is still cheaper to operate



.

[Gimmered]

you have to figure as soon as the system requires auxillary heat, that's the point where the furnace gets cheaper to operate

so, heat pump plus auxillary heat equals more power usage cost than just a furnace

now to throw a bump in the road sometimes if it's not that cold, but cold enough to use the auxillary heater lets say for 5 minutes out of each hour use, at that point the heat pump is still cheaper to operate



.

Dual fuel doesn't use auxiliary heat. It is heat pump or gas.

[drewski11]

Our gas rates are .90 for the first 20 therms and .69 after that. Electric is .08 a KW for the first 900 then .04 after that. Both have customer fees and taxes that amount to aprox $20 a month. No idea what my hp cop is but the ahri number for the system is 551617 if that helps. Actual temp where the hp can no longer maintain our house is 9 degrees. Economic balance point is?

wow, it get's cheaper the more you use? i need to move to Nebraska!!

[Airmechanical]

Dual fuel doesn't use auxiliary heat. It is heat pump or gas.

did someone say they did not know what a dual fuel system was

this is not the first time and it won't be the last time we been off subject

my statement was in regards to the difference in cost to operate a heat pump compared to a furnace

anyhow, have a good one!



.

[Joker]

Joker, I would double think that before saying you want to move to a colder place up north LOL. Our winters absolutely suck, and I am only in Indiana. I can't imagine what they are like even farther north than us.

Im a summer guy so I work all summer and sit around all winter. I would rather work all winter and be off all summer! ;)

[Joker]

wow, it get's cheaper the more you use? i need to move to Nebraska!!

Thats just socialist states control energy that cause high energy cost.

Everywhere else energy is somewhat cheap.

[tedkidd]

Joker,

I used zip code 76013 and 8.5 hspf. I assumed about 800 therm annual use/$400. Is that close? If you really only pay 45 cents per therm and 12c per kwh, your economic breakpoint is around 62 degrees.

Since electric and gas are somewhat tied together, those prices surprise me. Are you forgetting the per therm deliver charge?

If you take the therm cost to $1.00 - still a low number - the breakpoint becomes 44f. That's assuming a 95% furnace.

With an 80%er the breakpoints are 62f @45c and 25.6f @$1. Not sure why the inefficient furnace break point is impacted so much more dramatically by changes in fuel cost. This indicates a heat pump on an in-efficient furnace offers significant protection to swings in gas cost even when gas is really cheap, not so much if you have a high efficiency furnace unless the therm/kwh price is higher than 9/1 .

Might also have something to do with your temperature zone. Hard to pin down.

The other thing the numbers showed is a high efficiency furnace is likely to save about 20% in gas cost. Even at $500 annual gas cost that's a pretty good #.




Very rough numbers. I need your annual therm usage and KWH usage to true this model to you.

[Joker]

Joker,

If you really only pay 45 cents per therm and 12c per kwh, your economic breakpoint is around 62 degrees.



This is what I have found too in my area. NG being so cheap that its just not worth doing dual fuel or heat pump if you have NG. I have quized my customers for decades to come to my conclusion. Trane reps kept pushing dual fuel and claiming how great heat pumps were in against NG but not once have I seen it in my neck of the woods.

Most people really don't use heat or cool when lows are between 45 and 60.

With the manufactures coming up with 2 stage and 3 stage furnaces heat pumps just are not worth it when you add in loss of a/c efficiencies, cost of maintenance and cost of repairs.

Now if you have high NG and low electricity then this would be a whole other argument.

[martyinlincoln]

I think that's exactly why they're so popular in our area joker. Electric is dirt cheap compared to gas. Most of what the HP uses is in that 4 cent tier and gas is usually 80 cents to a buck a therm.

[Joker]

I think that's exactly why they're so popular in our area joker. Electric is dirt cheap compared to gas. Most of what the HP uses is in that 4 cent tier and gas is usually 80 cents to a buck a therm.

That would explain it. Electricity is relatively high here and NG is cheap.

[beenthere]

12 cts a Kilowatt hour, NG I want to say $4.5 per MCF. Not real sure. Pay online and could not find a rate. Dallas/Fort Worth Texas.

80K 80% gas furnace 2.5 ton 13 seer a/c 4 ton blower.

This is my bills electric/gas since December.
Month----- TXU----Atmos
7-----------144----12
6-----------81------11
5-----------61------14
4-----------71------17
3-----------91------78
2-----------76------120
1-----------59------131

Doesn't Atmos have a 16 dollar a month meter fee?

[Joker]

Doesn't Atmos have a 16 dollar a month meter fee?


$7. I found my bill. I pay $5.1 per MCF. I was close.

I used .4 MCF last month! LOL

Foamed walls is the way to go! I need to find a way to shut off some of the vents under my house that way my NG bill will come down. I have 60% peer and beam with 40% slab. I bake on the slab to keep the peer and beem side warm. I put return grills on my manhole(2 of them) openings. Great for summer suck in winter!

[tedkidd]

At those gas rates not sure how much you can justifiable spend based on gas savings. For comfort and ac savings this thread (http://hvac-talk.com/vbb/showthread.php?t=603512) may help.