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Conflicting info about heat pumps in Georgia

Posted by katy_bug (My Page) on
Wed, Dec 14, 11 at 12:14

Hi! Our 19 year old furnace died and instead of propping it back up we decided to do an energy efficient overhaul on the house. Because we currently have no heat, we art trying to get something installed as soon as possible and utilize as many rebates and tax credits as we can. Here are our stats:

* We live in Athens, Georgia (NE)
* House was built i 1961
* 1602 sq ft of conditioned floor area
* currently we have a
- 0.8 AFUE Natural Gas Furnace
- 9 SEER Central AC
* Georgia Power is our electric retailer and the rate is $0.10 per hWh
* gas rate is $0.72 per therm

We are looking for a good combo of efficiency and comfort. Everyone has a strong opinion on Heat Pumps and they offer conflicting advice. I need help from someone who is not trying to sell me something.

Our local HVAC people quoted us:
Lennox 16.2 seer 14acx-036 ac with an 80% 70K BTU horizontal gas furnace = $4095
10 year parts and compressor warranty. A 5 year coil warranty and a 1 year labor warranty

The HVAC people recommended by our energy auditor are out of Atlanta and they suggest:
16 SEER AMANA Heat Pump, 3 Ton, System Install - we are in the process of getting all the details and quotes on this one.

The energy auditor said a heat pump was determined through the Beacon Report to be the most efficient device and would also save the most money year after year in addition to getting the most back In rebates. Others say that the heat pump will never keep our house consistantly warm in the winter during the few extreme weather spells that we have.

Any thoughts?


Follow-Up Postings:

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RE: Conflicting info about heat pumps in Georgia

Katy

Mdl numbers are important.

You did not provide the Lennox furnace mdl number. The AC condenser is low end Lennox. I would not have it for my home.

If the rates you provided are all inclusive, nat gas would be cheaper to operate than a HP as long as furnace was a high eff mdl.

I would look at a two stg var speed 95% furnace model.

Where will new furnace be located? In a crawl space?

I have no idea about your budget.

My first choice would be a high eff furnace with AC.

Second choice would be high eff HP with 80% two stg VS furnace.

That would be my starting point.

IMO


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RE: Conflicting info about heat pumps in Georgia

Tigerdunes,
Thanks for your quick response. I don't have the mdl#s but I will request them. I am speaking to the HVAC people out of Atlanta today.

Our furnace is currently in the crawl space but we are going to move it out of the crawl space to a more accessible area for an extra $950.

Right now our budget is $5000-$5500 but I will consider spending more if it is worth it.

Any questions you recommend for me to ask the HVAC person while talking about our options today?

Thanks again.


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RE: Conflicting info about heat pumps in Georgia

FYI: going from a 9 to 16 SEER unit will give you a 'vast' improvement, ie lowering, in you electric bill for cooling.

I would also recommend a variable speed blower with the furnace so that the AC gets better humidity reduction in the summer.


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RE: Conflicting info about heat pumps in Georgia

Katy

Where is your ductwork located?

And could you elaborate why you want to relocate furnace from your crawl space? It is quite common in the South that furnaces are placed in crawl spaces. That's where mine is located.

IMO


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RE: Conflicting info about heat pumps in Georgia

Our furnance is located really far away from the crawlspace access and it is in a space that is so small, we are limited to which units we can purchase because of some of them won't fit. We basically have to army crawl under the duct work and sewerline to the other end of the house.
It will probably stay in the crawlspace, just much closer to the back of the house. They quoted us $950 to reconfigure the ductwork (which is also in the crawl space).

Another part of our energy improvements is to seal and insulate the crawlspace.


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RE: Conflicting info about heat pumps in Georgia

10 cents per KW hour is pretty reasonably priced electric. A heatpump should not cost much more than the same model A/C. I would go with highest efficiency single stage heatpump (14/15 seer) and an 80% furnace for your area. This shouldn't cost a fortune. I would run the heatpump at 30 and above. You get comfortably heated rooms with the heatpump because it runs longer with a warm heat. At 30 and above your getting about 300% efficiency. That means your getting 3 units of heat for every 1 unit of electricity consumed. It gets better in the 40's and up.

If your house is very leaky and un-insulated the heatpump won't work as well. I like heatpumps. It is true they don't do as well in the extra colder weather and if you have gas thats when I like the gas.

We are having a warm winter where I live and so far I've been running the heatpump most of the time. I run mine at 35 and above then below 35 the nat. gas takes over.


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RE: Conflicting info about heat pumps in Georgia

Katy

Despite the blind endorsement by previous poster, HPs are not for everyone.

Strictly on a BTU basis and assuming your rates are accurate and all inclusive, heating with nat gas with a 95% eff furnace is about 25% less expensive than a high efficient heat pump using a COP of 2.75.

Cost per 100,000 btu of useable heat
Electric baseboard: $2.64
Heat pump: $1.07
Natural gas: $0.74

I like facts that homeowners can take unto consideration when comparing fuel choices.

IMO


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RE: Conflicting info about heat pumps in Georgia

Hi Tigerdunes,
Yes . . . I agree that facts and math are more helpful when making my decision. Before you posted your numbers I found this calculator (www.eia.gov/neic/experts/heatcalc.xls) and came up with the following calculations:

Natural Gas at $0.74 per therm:
95% eff = $7.79 per million Btu
90% eff = $8.22
85% eff = $8.71
80% eff = $9.25

Heat Pump at $0.10 per kwH
9.5 HSPF = $10.53 per million Btu

So . . . I agree that Natural Gas is looking to be more cost effective than the Heat Pump option by about 25%.
I am thinking about the additional factors that may impact this calculation. Can you answer these questions?

* Is a heat pump typically significantly cheaper so that with rebates it would be more cost effective in the long run? Since we are doing a complete HVAC change out then we would need to compare the cost of a Heat Pump with a Furnace + AC unit, correct?

* Does the cost of electricity tend to fluctuate more or less than the cost of natural gas? We have seen our $ per therm go from $0.75 up to $1.25 and back down to $0.74 in the past 4 years. Does electrical cost do the same?

* What are your thoughts on dual fuel heat pumps?

Other things that we are doing at the same time is:
-Air sealing major by-passes in the attaic
-Fiberglass insulation to R-38 in the attic
-2" depth foam insulation on the crawl space ceiling
-Duct work sealing to all accessible ducts
-Sealing rim joists in the craw space with open cell foam
-Seal and insulate our attic access hatch.

Here is a link that might be useful: Heating Fuel Comparisoin Calc


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RE: Conflicting info about heat pumps in Georgia

Katy

Here are my ideas.

Dual Fuel systems are a good idea if one can leverage good electric rate versus backup furnace powered by fossil fuel like nat gas, propane, fuel oil.

Your rates do not support a dual fuel system simply because at the moment nat gas is so abundant and cheaper relative to electricity. I installed a dual fuel system 6 yrs ago when the gap between electric and nat gas was much wider and made a HP decision a no brainer. This is not true in your case. And in my situation, there is only a small advantage today using a HP down to my balance point and then switching over to nat gas furnace.

The best bang for buck is insulation and sealing up leaks. However looking at your list, I must caution you. You need to take into consideration your area/climate. Georgia has hot summers but moderate winters. There is overkill and the law of diminishing returns come into play.

I would recommend a good two stg var speed furnace 95% eff like
Trane's XV95 60 KBTU size with a good 15 SEER AC condenser.

IMO


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RE: Conflicting info about heat pumps in Georgia

Thanks for the recommendations.

For your comment "You need to take into consideration your area/climate. Georgia has hot summers but moderate winters. There is overkill and the law of diminishing returns come into play."

Which on the list do you consider overkill?


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RE: Conflicting info about heat pumps in Georgia

Katy

I would have to know the costs for each line item. Do you plan on doing any of this work yourself?

What insulation value do you currently have in attic?

R-30 is generally the standard for SE area/climate. I would want to know
the price difference between R30 versus R38.

All your ductwork is insulated both supply and return lines? If so what insulation value?

Does any of your home's living space have any hot/cold spots?

You have adequate return for your home?

You currently have no underfloor insulation? Cost of foam versus R19?

I am just brainstorming and trying to make you think about this list.

IMO


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RE: Conflicting info about heat pumps in Georgia

I think a 2.75 COP will be happening below 30 degrees. A good high efficiency single stage heatpump will have a COP more like 3.7 at 47 and above.

That changes things significantly. Even at 35 degrees a good single stage heatpump should be producing heat a COP of 3.25.

The cost of a heatpump isn't much more than the regular A/C. If gas prices go up, you have some extra protection. You will also get evenly heated rooms with the heatpump. I would only run the heatpump in situations of 35 and above for your situation. You could even do 40 and above if you liked.

I think its worth the extra investment.


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RE: Conflicting info about heat pumps in Georgia

No - we are not planning on doing this work ourselves.
All of this was recommended to us by our recent HERS report.

To answer your questions:
We currently have old R-6 batts with a little fiberglass blown over top in areas.
None of our ductwork is insulated or even sealed.
We don't really have hot or cold spots. We have one bedroom that stays warmer than the rest, but not by too much.
I don't know what you mean on "adequate return".
No underfloor insulation and wood floors. In some spots, you can actually see lights from the house through cracks between the floorboards when in the crawlspace.

Here is what we were quoted for supplies plus installation:
$1,095.00 - Air sealing major by-passes in the attic
$1,425.78 - Fiberglass insulation to R-38 in the attic
$1,205.10 - 2" depth foam insulation on the crawl space ceiling
$595.00 - Duct work sealing to all accessible ducts
$463.50 - Sealing rim joists in the craw space with open cell foam
$355.00 - Seal and insulate our attic access hatch.

I really appreciate all your input on this.
Katy


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RE: Conflicting info about heat pumps in Georgia

What I say about the previous post is pure nonsense. He is obviously not schooled in relationship of HSPF and COP.

The 2.75 COP is based on a rating of 9 HSPF at 47 degree which is above average for a good matching HP system. Of course the actual COP depends entirely on the efficiency rating from AHRI. The COP drops as the outside temperature drops.

Without knowing the actual specifics, I would say the 2.75 COP I used in the fuel comparison was quite generous rather than understated as the above poster implies. He is simply wrong.

As far as the cost of the HP VS AC, you can plan on spending minimum extra $500 plus for a high eff model not including the additional cost of controls.

And the suggestion about evenly heated rooms is more a function of a good designed ductwork system rather than saying something that a HP does not do.

Strictly from operating costs and your rates, DF is not a your best choice.

Katy

To your list.

1.if your ductwork is not insulated, then it needs to be insulated. R8.
2.I would get a price comparison on underfloor insulation with R19 and compare versus foam.
3.do you plan on removing old insulation in attic and replacing with all new?
4.not clear about line item #1

Return refers to return air ductwork. Do you have individual room returns or central return(s).

Do you have whole house air filter cabinet on existing furnace?

Post back.

IMO


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RE: Conflicting info about heat pumps in Georgia

I've seen many different brands heat pump specifications. Most new heatpumps are getting 3.5 COP or better at 47 degrees.

Why would they post these numbers on their website on the specifications for their models? This isn't for the outdoor condensor alone, this is for the entire system.

I have dual fuel. My bills are smaller with running the heatpump in milder cold weather. I've seen my neighbors bills who run gas only for heating and I've compared. And i pay 12 cents per KWH which is not that cheap of electricity.

Does the HP cost $500 more than the A/C? $Very possible. Controls add cost to. If the original system were to be $5000 without the heatpump and $5600 with the heatpump, I think its a good updgrade. This is just my opinion.


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RE: Conflicting info about heat pumps in Georgia

Katy

Another thought.

What type if any attic ventilation do you have in place?

IMO


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RE: Conflicting info about heat pumps in Georgia

Okay - finally got the model info from the HVAC company. They are suggesting these below at $5200 for both situations.

Heat Pump - 16 SEER AMANA. $400 GP "Conversion" Rebate plus save $30 a month access charge if no gas bill (furnace is our only gas appliance).
http://www.amana-hac.com/Home/Products/HeatPumpSystems/16SEERASZC16/tabid/856/Default.aspx

Split System- 16 SEER, 95 AFUE (Same Price, no conversion rebate, may have to move the furnace to a new location to accommodate size difference)
http://www.amana-hac.com/Home/Products/AirConditioningSystems/16SEERASXC16/tabid/854/Default.aspx
http://www.amana-hac.com/Home/Products/GasFurnaces/95AFUEAMVC95/tabid/1162/Default.aspx

They offer 10 years parts and labor warranty on their Amana products.

Back to calculating gas or heat-pump . . . how do I account for the fact that I would pay $360 less a year to not have gas because we wouldn't have to pay the access fee each month?

Your other questions:
We have a central return.
The filter is located on the furnace.
We have two attic ventilation fans installed about 4 years ago.


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RE: Conflicting info about heat pumps in Georgia

To speak to your question about the costs of gas and electric: I have seen that gas prices fluctuate much more than electricity, but it depends on your state. Electrical rates are normally regulated by the public service commission of your state. Some states have deregulated electric rates and have seen these rates go up.

It is more a supply/demand thing with gas. At the moment, there is more supply that demand.

I think the systems you are talking about are a 95% gas furnace with an AC, an 80% furnace with a HP, and perhaps a HP by itself (electrical backup heat).

There are installation cost differences between a 95% furnace and an 80% furnace. These differences are in the flue arrangement. They may not mean much if anything to your installation costs.

The HP takes over the function of the AC in summer, providing cooling. It is just as efficient in cooling as the same rated AC unit. It also does heating. It will heat down to a point where the auxiliary heat is activated. In your case we are talking gas. Or electric strip heaters if you dont go gas.

Since you have gas already I think you should not do the HP only with electric heat strips. Doesn't make much sense here. Using the heat strips would be nearly 3-times more expensive than the HP or perhaps the gas.

You would be paying the $360 if you never used the furnace. Not likely. The question is, is this the minimum payment for gas? That is, if you use less than $30/month will they charge you $30 or the amount you used? Otherwise this should be the same as you are doing now since you already have a gas furnace.

To figure out some of the billing amounts, try this. Look at your peak electrical usage during the summer and your usage during the spring/fall when you don't use AC. This should give you a rough guess for your AC usage alone. A new HP/AC of 15 SEER should lower your AC usage by . This should give you how much you'll spend on cooling.

On heating, you have your current gas bill using an %80 furnace. Using a 95% will lower that by 15%.


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RE: Conflicting info about heat pumps in Georgia

Yes, the $30 per month is the "delivery charge" and we pay it regardless of gas use. We also pay it in the winter on top of our gas use.


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RE: Conflicting info about heat pumps in Georgia

Do you "need" NG at all. Fireplace, range etc.

If you have NG already, then presumably you have NG appliances including hot water. In higher use situations, NG will save $360 over electricity (at your rates) just for hot water. That has to be accounted for.

I live in NC with similar rates although our NG is more like $.95 now but we pay $10 a month for delivery. Since I have solar hot water (with electric backup), I don't save enough in a dual fuel setting to justify the $10 a month. But we have gas fireplaces and a NG range (which was mandatory) and a NG grill. But strictly based on cost, I know that going all electric would be the cheapest. Our NG bill last year was around $120 ... for the year. So 1/2 our NG cost was delivery - so we payed just under $2 a therm. We have 5000 sqft so once your are better sealed/insulated, you can really see how dual fuel is overkill.

For you, long term, you should probably go all electric. You need to get a heat pump hot water heater which could cost less than even NG (depending on where your hot water heater is located).

NG has been more volatile. Electric will likely climb in a linear fashion. Mandates regarding renewables and potential carbon based legislation will drive electric rates up but may not change NG rates. But it is all conjecture. I'd go all electric but maintain the ability to change back if/when things become favorable.

I think all your upgrades are reasonable but not necessarily cost effective at those prices. I am guessing that Athens is a high cost area regarding "green" projects. When we built, it cost $200 to go from r-30 to r-40 in the attic. But if you have no insulation, then that price isn't terrible.


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RE: Conflicting info about heat pumps in Georgia

I know how gas fluctuates and I also know electric rates along with any other energy source will probably continue to rise but at least electric doesn't have the huge swings gas has in the past. I recommend a 14-15 seer with 80+ furnace when available unless your up north with brutal winter weather. I know right now the 95% is better than a heat pump but what about next season? If possible I would try for 95% and heat pump it. Go 95% in the plan first and try to squeeze in the 15 seer hp if possible.

Just my opinion


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RE: Conflicting info about heat pumps in Georgia

OP's location is Athens, Georgia with hot summers, moderate winters.

a 95% eff furnace paired with HP is overkill for that location and climate.

Homeowner will need to decide whether to spend extra dollars on HP option where some possible future use makes economic cents.

At this very moment, a HP does not make cents.

IMO


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RE: Conflicting info about heat pumps in Georgia

Just a few obsevations... I live about 2 hours from you. I have a heat pump because gas is not available in my area. Unless you are going to do most or all of the improvements to your house you listed above do not get a heat pump ..... you will freeze with a house that is that pourous. I always ask my customers how warm they like it in the house... that makes a difference also.

But here in Ga your main concern needs to be getting the most eff a/c side you can afford. you use it around here 9 months out of the year sometimes.


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RE: Conflicting info about heat pumps in Georgia

Okay - thanks everyone for your input. I spent the evening looking over my bills and refiguring the math. I went with a the heat pump for several reasons.

#1 - Going complete electric. The furnace was our only gas appliance and once I did the math, I realized it wasn't worth it to keep gas supplied for that because of the delivery charge. (see #2)

#2 - in our case, electric heat is cheaper. See if you follow my math:

Electric - Right now we pay $0.10 per kWh with an additional 12.77% service charge for various things. I didn't include the sales tax in this calculation b/c it is the same for both services.
With fees, that would be $0.1135 per kWh
With a HP at 9.5 HSPF, we pay $11.95 per million Btu.

Natural Gas - Right now we are paying $0.74 per therm with a $27.99 per month delivery fee (which is standard for our area).
Based on last years usage:
12 months x $27.99 = $335.88
We used 681 therms x $0.74 per therm = $503.94
Total cost of $839.82 / 681 therms = $1.23 per therm with fees.
With a 95% Eff furnace that ends up being $12.95 per million Btu.
Since we are improving the insulation, our therm usage may go down by 30% but our monthly service charge wills stay the same so:
[(476 therms x $0.74 per therm) + $335.88 delivery charge] / 476 therms = $1.45 per therm with fees
That would drive our our cost per million Btu to $15.26

So . . . Heat Pump Unit and Furnace + AC Units at equivalent efficiency cost the same thing - $5,200
Heat Pump costs $11.95 per mil Btu for heat
Furnace costs $12.95-$15.26 per mil Btu for heat

I am assuming the cost to cool will be equivalent since both units will use electricity and are equally efficient.
In addition, I get $400 rebate on the heat pump.

#3 - Our mild climate. While anecdotal, I talked to several people in my area with heat pumps and they were very happy with the temperature control in their house. No one had trouble with the heat pump keeping up during our short and infrequent cold snaps.

#4 - Heat pump is greener. Natural gas is a fossil fuel and while fossil fuels are also used to generate electricity, there is always the opportunity for renewable energy sources to be introduced. If we get a NG furnace, we are stuck to only using fossil fuel as an energy source.

So . . . that is why I decided on a heat pump.
And yes, we are addressing all the insulation and air sealing issues so the house will (hopefully) not be drafty and conducive to heat pump being able to adequately heat our home.

Thanks everyone!!!


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RE: Conflicting info about heat pumps in Georgia

I agree with your logic. Even if you use electric strip on the cold snaps, you are better off. And electric strips are just as hot as NG

Wow - that is lot of heat usage for where you are. You may save more than 30% with upgrades.


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RE: Conflicting info about heat pumps in Georgia

Good job. Heatpump should work well vast majority of the time with your mild climate. Sometimes when its really cold you will be throwing in some auxiliary electric but thats not the majority of the time.

Thats an expensive monthly gas service fee. You can buy lots of electricity with that. The gas company is just asking your to cancel their service.

What do you heat your hot water with though? Is your stove electric currently?


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RE: Conflicting info about heat pumps in Georgia

Katy

Out of the choices available to you, the one you selected is the worse.

Post back during your first below freezing weather and let us know how system is performing including family's comfort.

IMO
Good Luck!


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RE: Conflicting info about heat pumps in Georgia

neohioheatpump - yes, stove and hot water heater are electric.

tigerdunes - I feel pretty good about my decision based on the research.

I will let you know how things go when we get everything done!


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RE: Conflicting info about heat pumps in Georgia

you will be just fine then. That extra $300 per year can go towards the electric you'll be using during the cold snaps. During the vast majority of your weather the heatpump will give you inexpensive and comfy performance.
If your home is on the leaky side now, do some insulating.

One of the best bangs for the buck is insulating the attic. If you have a basement, or your ducts are accesible make sure leaks are sealed in ductwork. Seal leaks in unfinished areas of the house if you can feel cold air leaking into the house during cold snaps. There are plenty of improvements a homeowner can do themselves without being very skilled that will reap rewards in energy saving and comfort.


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RE: Conflicting info about heat pumps in Georgia

Katy- good job of doing the analysis and coming to a reasonable conclusion. I'm not sure why tigerdunes is being so cranky. The point that NG prices tend to be more volatile is a really good one. That they happen to be advantageous now doesn't mean they always will be.

We have a dual fuel system in ATL. In part we did the HP b/c NG prices were much higher when we put it in. The NG furnace runs below 30F and locks out the HP. It's still painful to get the NG bill on top of the one from GA Power, but we have gas water heaters, a gas range, and a gas grill. So no cutting the cord there.

With the dual fuel setup, there are periods when temp is right above HP lockout (30F) that comfort is borderline. The HP just isn't putting out much heat. With an all-electric system you won't have to worry about that as much since the strip heat can run at the same time.

Don't forget about the air filter. The deeper ones are great. We had an Aprilaire on our old system (came with house) and we put in a Honeywell with the current system. The filters themselves aren't cheap (~$30 ea for Honeywell) but they do a very good job and last a long time. HD carries less-expensive replacements now, but they're squirrely about the performance rating, so I guess they're cheapo like a lot of other stuff there.

My parents live in AL and just put a new system in. I tried to feed them info similar to what you used on calculating operating costs. In the end, they just put in a 2-stage 80% NG furnace with VS blower based on installer recommendation. So you win some and lose some in getting folks to make informed decisions.


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RE: Conflicting info about heat pumps in Georgia

"The COP drops as the outside temperature drops."

And specking at 47F does not indicate what happens at that nasty point of 32 F (or even close to it).
Frost starts to form on the evaporate an the the heat output falls badly.

All the engineering in the world is not going to change the freezing point of water, and as soon as you get near it frost becomes an issue.


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RE: Conflicting info about heat pumps in Georgia

katy

Believe it or not there really wasn't a bad decision to make. Either way you went. But not to keep this going or anything but i am real curious because nobody really ever asks this when they have heat pump vs gas debates but what temp do you like it in the house? are you a 68 degree person or a 78 degree person in the heating season?

Because unless you have a bubble for a house you will not like the heat or the bill on a heat pump if you like it 78 in heat........ But if you are a 68 degree person in heating season you will like it just fine.


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