Heat pump vs. Gas Furnace?

[Daltex]

What enviornment does the benifit of the heat pump for heating outway the cost? I have been trying to educate myself on the proper system to replace the worst of the 4 units I have and wouldn't mind spending a little more if the savings is justified. I had read the hp outputs a cooler vent temp then the gas so I had written it off but with a VS blower this cooler heat would be less noticable correct?

House stats- zip 75603 on a lake with the house totaly exposed to the wind. The house was built in the 1950's and has no ext. wall insulation. The cost of elect. is around .10 as is gas. I need to replace an old eubank ac/gas furnace upstairs and a newer package unit w/ elec. heat down. Being on the lake, the humidity is a bit higher than the weather station at the airport just up the street a few miles.

Thanks for any advice.

[firecontrol]

You can possibly get hundreds of different opinions on your question. While you're waiting for them to show up, how about playing with this calculator:

(http://sagoro.wrightsoft.com/bryant/default.aspx)

and help educate yourself so you can ask the right questions when you start getting quotes from dealers in your area.

You'll have to go to the Bryant website below to get model numbers as the calculator is set up for those numbers only. This will at least let you play with what different equipment choices will do to your energy bills.

http://www.bryant.com/products/index.shtml

Good luck.

[Daltex]

Thanks FIRECONTROL! I'll do my educating and see what I come up with.

[2old2rock]

Not having any insulation in your walls is going to be a major factor. A load calculation will be needed, but it will only be useful if all information you, (or your contractor) apply is accurate.
Might want to look into adding some insulation. Keep in mind that sizing a system now, then adding insulation will result in a system with too much capacity.
Good luck.

[tomgeer]

Do both

Hybrid system

Will save money

Will give you the choice to choose source of heat ( heat pump, gas)

[Daltex]

Not having any insulation in your walls is going to be a major factor. A load calculation will be needed, but it will only be useful if all information you, (or your contractor) apply is accurate.
Might want to look into adding some insulation. Keep in mind that sizing a system now, then adding insulation will result in a system with too much capacity.
Good luck.

I agree. I've been on this site for a while now and know about the man. j,d. I'm adding insulation to the attic after the new ductwork is installed but the walls would require foam and the house is over 5000 sq. ' so $$$. I also have a wall of windows (single pane old aluminum swing outs) on every wall. I will have the contractor figure in the additional attic insulation in his load calc.

I was told by a contractor friend in Dallas that he would charge me a grand more if he was doing it and I added the insulation before he installed the new ducts. Joking but I got the point.

Looked at the Bryant site as mentioned before and still don't know what the best climate for a heat pump is. Almost no one in my area has one but it seems the climate could be perfect. I just don't yet know what the perfect climate is.:confused: I'm guessing- sizing for the heat gain would require a HP that is larger than necessary to heat the moderate climate but I was thinking a VS blower would solve that??:confused:

I wanted to have as much info before the bids so that I didn't put them through more hoops than necessary. Also didn't want to find out later that a HP would be better and have to have them re-quote.

[tomgeer]

Think LENNOX

Do LENNOX

Live LENNOX

Save with LENNOX

look for manufacture rebates

[Daltex]

Do both

Hybrid system

Will save money

Will give you the choice to choose source of heat ( heat pump, gas)

Was considering that. Maybe a 80% gas for the few nights below 30* and to quickly ramp it up quicker when necessary.

[Daltex]

Think LENNOX

Do LENNOX

Live LENNOX

Save with LENNOX

look for manufacture rebates

Now what model should I choose? What about a LENNOX?:D

[Zeiss Nut]

at Zip code 75603

I don't imagine you have a very long winter do you ??

Mostly Cooling isn't it ?

[Daltex]

at Zip code 75603

I don't imagine you have a very long winter do you ??

Mostly Cooling isn't it ?

Last 365 days:
Degree Days:
Heating Degree Days (base 65) 35 6 0 2036
Cooling Degree Days (base 65) 23 7 0 2588
Growing Degree Days (base 50) 38 17 0 6325

[tomgeer]

Was considering that. Maybe a 80% gas for the few nights below 30* and to quickly ramp it up quicker when necessary.That is what I have. Lennox 2 stage with a 15 seer heat pump.

[beenthere]

The HP would be sized to the cooling load. If sized to the heating load, you would end up with high humidity in the summer.

You said electric is 10 cents and so is gas. Guessing that you mean gas is 10 cunts per CF, that make it $1.00 per therm, using a 90% furnace for duel fuel.

You would only see a savings as long as the HP's COP was above 2.65, and it didn't go into defrost. At the rates you posted. So do you have a lot of days in the heating season that are 40*F and above.

[tomgeer]

Now what model should I choose? What about a LENNOX?:D
G71p With a xc21 and a pure air:rolleyes:

[hangfirew8]

What enviornment does the benifit of the heat pump for heating outway the cost? I have been trying to educate myself on the proper system to replace the worst of the 4 units I have and wouldn't mind spending a little more if the savings is justified. I had read the hp outputs a cooler vent temp then the gas so I had written it off but with a VS blower this cooler heat would be less noticable correct?

House stats- zip 75603 on a lake with the house totaly exposed to the wind. The house was built in the 1950's and has no ext. wall insulation. The cost of elect. is around .10 as is gas. I need to replace an old eubank ac/gas furnace upstairs and a newer package unit w/ elec. heat down. Being on the lake, the humidity is a bit higher than the weather station at the airport just up the street a few miles.

Thanks for any advice.

Buy a gas furnace for instant heat, quick recovery from a cold soak, and keeping up with the wind on a cold, windy day.

Buy a Heat Pump for economy, and no other reason.

Put them both together for a very comfortable system with good economy but higher upfront costs. In TX, you can get a modest 80+ system and it will serve you well.

I went into adding a gas furnace to go dual fuel with the lowest possible energy costs in mind. The resistive electric backup was breaking the bank on cold Winter months. I came out realizing my highly efficient, mod gas furnace with VS fan was a break-even at best when it came to energy cost, but oh, the comfort difference.

I got my economy by removing a layer of felt-like lint from the bottom of the Heat Pump's A-Coil during the install. Now my Heat Pump works like it should.

-HF

[beenthere]

I got my economy by removing a layer of felt-like lint from the bottom of the Heat Pump's A-Coil during the install. Now my Heat Pump works like it should.

-HF

If you get it serviced every year, you won't get that layer of lint.

[timby]

The HP would be sized to the cooling load. If sized to the heating load, you would end up with high humidity in the summer.

You said electric is 10 cents and so is gas. Guessing that you mean gas is 10 cunts per CF, that make it $1.00 per therm, using a 90% furnace for duel fuel.

You would only see a savings as long as the HP's COP was above 2.65, and it didn't go into defrost. At the rates you posted. So do you have a lot of days in the heating season that are 40*F and above.

Please forgive me for hijacking the thread .... :o

I continue to see COP ratings but only associated with HP's and Geo-thermals. I don't quite understand how a HP can produce more than what it takes in. :confused:

IF a unit costs x-amount to cool how can it be more efficient to use it to heat?

Sorry .... :o

I now return the control of your sets back to you .... :D

[beenthere]

Heat pumps don't make heat.

They absorh heat from the outdoor air(air to air HP ), and pump it to teh indoor coil, where the heat is rejected to the indoor air.

The warmer it is outside, the more heat there is that they can absorb.
It cost less to pump the heat, then it does to convert another form of energy to heat energy.

[timby]

So what your saying is the an HP takes the outside heat and pumps it to the inside as well as condensing it. This heats the air. So the HP really doesn't generate heat. It just moves it around.

So as long as the temperature difference is not too high the efficiency is much better than generating heat via burning fuel or using a heating element.

I think I got it. Just seems weird ....:cool:

[beenthere]

Correct, the cooler(cooler then the hot gas) air in the house absorbs the heat from the hot refrigerant gas, and as it gives of its heat, the hot gas condenses to a sub cooled liquid.

[beenthere]

I think I got it. Just seems weird ....:cool:

Well, do you think this is weird.

You can get more heat out of 212*F steam, then you can out of 220*F water.

[Daltex]

Thanks for all the replies. Summary: Cost more for HP upfront but with dual fuel (and properly serviced- Beenthere:)) should be less expensive to run. The best use is any climate but the energy savings is based on fosil fuel rates vs. electric rates. I know I could use electric strips but then the cost of usage would be greater (unless electricity is much cheaper than fosil) but the systems initial cost would be lower.

Similar systems: cost least to greatest / efficiency least to greatest

standard ac w/ elect. heat
standard ac w/ gas heat
HP w/ elect. strips
HP w/ gas furnace

Am I close? Thanks!

[hangfirew8]

If you get it serviced every year, you won't get that layer of lint.

Oh? Please explain this.

I had it serviced, if not every year, almost every year. At no time did any service man drain the refrigerant, pull apart the air handler, separate the electric coils from the A coil and vacuum off the bottom of the coil.

If I had it serviced all six instead of four years out of six, how would have that mattered? Is there some secret schedule for complete disassembly and cleaning that I somehow skipped? :rolleyes:

-HF

[beenthere]

Apparently so.
Are you getting the discount price annual service. Where the tech is the guy just out of school. Low air flow over the indoor coil shows up when you check the charge.
Now if the techs your getting are looking at pressures, and not saturations, SH, and SC. You aren't getting good techs. And should say something to the company thats doing your service.

[Daltex]

If you get it serviced every year, you won't get that layer of lint.

I guess someone didn't understand you meant "properly" serviced.:)

[hangfirew8]

I guess someone didn't understand you meant "properly" serviced.:)

Yes, those someones would be the 20-some year experienced techs from two different local companies that have been servicing my HP.

-HF

[luckyair]

Was considering that. Maybe a 80% gas for the few nights below 30* and to quickly ramp it up quicker when necessary.

Let's cut to the chase here. Most likely your electric service is not big enough to hand the 20kw - 305kw of back electric heat that comes with a (2) heat pumps. Unless you are prepared to spend another $1000 - $2500 for electric service upgrade then you cannot do the heat pump.

Is the power wire coming from the pole old also? How much to rebuild your electric service?

Forget about a hybrid system, same problem for electric. And not very many manufacturers make gas package unit with heat pump back up.

[luckyair]

Buy a Heat Pump for economy, and no other reason.

-HF


this here ain't Maryland, ya'll

[beenthere]

Yes, those someones would be the 20-some year experienced techs from two different local companies that have been servicing my HP.

-HF
Then you know not to use those techs/companies anymore.

[tomgeer]

good idea to drain r22 from system .

like changing oil

must change after so many miles:rolleyes:

[Daltex]

Yes, those someones would be the 20-some year experienced techs from two different local companies that have been servicing my HP.

-HF

Now, thanks to Beenthere, you'll know to make sure next time you hire a company to do PM checks, that they check the SC, SH. That's what's great about this forum, you learn something new every day.:)

[Daltex]

Let's cut to the chase here. Most likely your electric service is not big enough to hand the 20kw - 305kw of back electric heat that comes with a (2) heat pumps. Unless you are prepared to spend another $1000 - $2500 for electric service upgrade then you cannot do the heat pump.

Is the power wire coming from the pole old also? How much to rebuild your electric service?

Forget about a hybrid system, same problem for electric. And not very many manufacturers make gas package unit with heat pump back up.

I have 2 package units and 2 splits. The package units are both electric heat. Don't know the size strips but AC's are 4 ton and 2 ton. I assume the strips use more juice than 4 HP's combined but I'm just guessing. I think 305kw of back electric heat is way more than I need. Maybe a mis-type on your part. I was considering getting a quote on replacing the split unit with a hybrid. Don't see this being a problem. I may be wrong. I was wondering if they made a gas pack hybrid but could use strips if elect. service can handle.:confused: I'm not an electrician but my highest elect. bill last summer (previous owner's records) was over $800 so alot of juice flows through the lines. If the properly sized, properly installed HP's use more than this than I may be installing a windmill.:rolleyes:

[Jack2007]

Guess I need to look for a different company also. Never saw the "A" coil cleaned or even inspected.

After reading this forum, sometimes I get the feeling only "hacks" are in business around me.

I had two estimates last year. Both asked what I wanted, all I knew at that time was a "manual J". They never suggested different possibilities.

I had an aquaintence who is in the business, he suggested tearing out all my duct work. When I asked why, he said he did not like duct board. That would cost as much as a complete new system.
*sigh*
.

[Daltex]

Guess I need to look for a different company also. Never saw the "A" coil cleaned or even inspected.

After reading this forum, sometimes I get the feeling only "hacks" are in business around me.

I had two estimates last year. Both asked what I wanted, all I knew at that time was a "manual J". They never suggested different possibilities.

I had an aquaintence who is in the business, he suggested tearing out all my duct work. When I asked why, he said he did not like duct board. That would cost as much as a complete new system.
*sigh*
.

I think Beenthere was implying that you can check the sub cool, super heat to evaluate the evap. coil without tearing into it. Your company may have been taking these readings. I would just ask next time.

[hangfirew8]

I think Beenthere was implying that you can check the sub cool, super heat to evaluate the evap. coil without tearing into it. Your company may have been taking these readings. I would just ask next time.

Sorry to have hijacked this thread.

The in-law apartment gets a regular maintenance soon, I'm calling a different company and asking for a super heating/super cooling check. We'll seewhat the reaction is- "OK", "we only do that if it's broke" or deer-in-the-headlights-look. :confused:

-HF

[beenthere]

By checking SH, and SC the tech should be able to tell if there is an air flow problem.
Then he knows to check filter, and to make sure all grilles and regs are open and not blocked. And then he should know to check the blower, and if all is good with the blower, the coil needs cleaned.

Don'r need to rip things apart to see if its dirty or not.

[luckyair]

I think 305kw of back electric heat is way more than I need. Maybe a mis-type on your part.

Wow! when I make a typo I make a big one. No, I meant to type 30kw not 305kw.

My apologies on my previous post. I thought you were trying to replace a gas pack with a heat pump.

[ndiglo]

Did you say the house is on the lake? Why not go GEO? Ask a contrcator in your area if it is an option in your area.

[Daltex]

Did you say the house is on the lake? Why not go GEO? Ask a contrcator in your area if it is an option in your area.

No one on the lake has done it. The contractor that did service for me gave me a quote on a standard system and I asked about going with a geo system and he said wouldn't work. I know now that it would work but I think the payback would be impossible to recover. Also no one with experience installing.