80% vs 95% efficiency and Recommendations

xrayvisionOctober 14, 2010


Need to replace my furnace in Lake Tahoe, NV. It is a vacation home, so can't get the federal tax credit. So the two questions I have are:

Should I go for the 80 vs 95% efficient. It is about $1500 difference in price, will I ever make up that $$$

What brands and any other recommendations?


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I didn't know that about vacation homes and tax credit.

Everytime I've been to Lake Tahoe, it has been pretty cold. That being said, I don't really know the climate there. But I imagine it is cold enough to warrant a 95% furnace or even more.

Here is the thing. The efficient units are in demand right now because of the tax credit. If you can wait until the tax credit expires, the manufacturers may have a glut or maybe more interested in dealing. So I'd wait and get a 95%

The reason to do a 80% today is in a dual fuel situation, a mild climate, or a lightly used vacation home. You just need to look at prior expenditures.

For example, last winter $1000 total on a 80% system. So you used 1000 therms to create 800 therms worth of heat. A 95% would have needed (roughly) 850 therms for a savings of $150. Now where could you get a guaranteed 10% tax free return for your money?

Now if you only spent $500 last winter - then I'd have to go with the 80%....

Is a 90% an option? For me that was a no brainer in new construction since it was cheaper than a 80% because of the chimney requirements. I only used $200 last winter in a dual fuel setup.

    Bookmark   October 15, 2010 at 5:41AM
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I looked up the temps and for the vast majority of the time a heat pump could probably do the job and still provide a 2-1 or so heat to kwh used ratio or better which is good. It still does get plenty cold though so I would say it is a toss up depending on your electric vs gas rate and what the long term projection for rates in the future might be.
The rate increase calculation is very much of a guess but some helpful information is if you research and find out that a large portion comes from hydroelectric or some other means that does not consume coal it might not see the increases a highly coal operated utility might see. The EPA and greenies are going to push hard for carbon credits and ways to charge the coal plants depending on emissions which will eventually be passed down.

If both are high I would consider the 90% option. Usually I would say southern states where it is warmer and decent electric rates go 80%.

15 seer with demand defrost and txv which should be standard equipment to achieve 15 seer are a must.

    Bookmark   October 15, 2010 at 11:06PM
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Any particular recommendations on brands?

    Bookmark   October 18, 2010 at 8:01AM
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several questions.

how much is vacation home used?

do you even need AC for this location?

how long do you expect to own this vacation home?

what size furnace are you replacing?

your fuel source is nat gas or propane?

since the tax credit is not in play, there are good alternatives between 80% efficiency and 95% efficiency furnaces.

I would want a furnace with good warranty and with st steel heat exchanger.

post back with some answers and I will make a couple of recommendations for you.


    Bookmark   October 18, 2010 at 8:26AM
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Thanks Tigerdunes

This is our first year owning the place

Don't know how many months we need heating, but plan to primarily use it during the Winter and Summer. In Winter hope to use it most weekends. We plan to use it occasionally in Fall and Spring.

We don't need/have AC

We plan on keeping the place forever (hopefully)

Natural gas is fuel source

I don't know the size of the furnace unfortunately. The condo is 3 stories and is appox 1700 sq ft (not including a studio apt on bottom floor next to garage that is not connected to central heat -- since getting a new furnace, is connecting that room to central heat something i should/can do? It is my office and right now plan on using an electric heater when I use it)

Thanks everyone for input!!!

    Bookmark   October 19, 2010 at 8:40AM
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I will assume you are more interested in quality,comfort, reliability and that price is not the driving factor.

I suggest you find out what size existing furnace is. Usually it can be found on a dataplate on the furnace or perhaps on the inside of the control panel. where is furnace located?

sometimes condo associations have restrictions/covenants on what they can and can not do and that includes HVAC.you might want to check on this.

Otherwise I would get a properly sized two stg 95% eff VS furnace. I can suggest several if you are interested. Dealer can advise possibility and practicality of adding heat to studio apartment. How big is studio apt? A small electric HP minisplit system might be a good alternative if studio apt will not be used on a regular basis.


    Bookmark   October 19, 2010 at 10:14AM
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Thanks Tigerdunes

    Bookmark   October 21, 2010 at 5:48AM
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Another thing to keep in mind when choosing between 80% and 95% is where the furnace will be physically located. If it's located in an unconditioned space, then the moisture condensation issues that accompany high-efficiency furnaces may dictate that you pick the 80% unit. Some contractors will outright refuse to install a high-efficiency furnace in an attic for this reason.

    Bookmark   October 24, 2010 at 10:07AM
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Had a few bids

Most recommended an 80% efficiency furnance. Changing the flue and drain for the 95% would be a significant expense, and given that I cannot get the tax credit 80% seems like the most economical.

Currently is a 125k BTU upflow in a closet, so "21 inch wide furnance is gonna be tight". Many have said 100k btu would be fine (current furnace is like 60% efficient they said)

Given that information, any particular brand you would recommend?

The bids I got
-Bryant 110k btu 2 stage 80% - $2510

-Rheem 105k btu 80% - single stage - $1885(the contractor said they do not have 2 stage 80% Rheem) But said could also get a 2 stage Goodman 105k btu for same price $1885

- But another bid for Rheem 120k btu 2 stage 80% for $2800, 1 stage for $2720

- Hiel 100 k btu 80% 2 stage - $2487

- Carrier person gave me a bid over phone, could not come up this week for 110k BTU 2 stage 80%, approx $2800

Some come with new thermostat. Some include permit, some said we could permit it for extra $120. My gut is that the "non" permit guys are a red flag, even though got all of these from Better Business Bureau website.

Anything else I should ask about

thanks again

    Bookmark   October 28, 2010 at 6:59PM
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I would be careful abouut sizing. It is difficult for me to believe you need more than a 100K 80%. Maybe less. Ask dealer to perform load calculation. You might check with neighbors and see what size they have. Is condo an interior unit or exterior unit? this can make a difference in BTU load.

If price is not the driving factor, I would want a two stg variable speed furnace. And I do recommend a good basic whole house 4-5" pleated filter media cabinet where filter changeout is easy and filters last up to one yr before changeout. Of course you would also need a good two stg thermostat like Honeywell's VP 8000 series. Do this right and new furnace will pay off in longevity and reliable service. you do want st steel heat exchanger.

I would look at American Std two stg var speed model and good basic Honeywell filter cabinet.


    Bookmark   October 29, 2010 at 9:00AM
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Sounds like the Filter Cabinet is extra? And if extra, what are the benefits? Is there still a place to put a filter in the furnace without the filter cabinet?

Thanks for the help and my whirlwind education on furnaces everyone!!!

    Bookmark   October 29, 2010 at 5:17PM
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Many of the bids I got do not include obtaining a permit, while others do. One place said it would be $500-600 more to pull a permit. How important is getting a permit?


    Bookmark   November 4, 2010 at 5:50PM
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This is interesting. In my locale, a permit is not required to replace an existing unit. But I would be curious to know for the pro's if this is standard practice in other places, and what would require getting a permit when a replacement is being done (new insulation, new gas service, new electrical, etc).

    Bookmark   November 4, 2010 at 7:07PM
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California requires permits for any furnace replacement---dunno about other states. Ours was included in the quote for all but one contractor, and was pretty inexpensive (a little over $100 I think, which was a flat fee for all related work---they moved both electrical and gas, but we didn't decide to have them do that until the day of install). I like knowing they did the work to code, so it seems worthwhile to me---and we more than made up the cost in rebates from the power company, which require a final permit before they send you the check.

    Bookmark   November 4, 2010 at 9:38PM
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Permit here. We need a permit to change out a gas range since there is a new gas connect made. You bet that changing a furnace needs a permit.

Now - I had a new HP system downsized about 3 months after install since they put the wrong size in. No permit was pulled but I suspect technically they should have.

    Bookmark   November 5, 2010 at 6:38AM
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depending on state/locality, pulling a permit is often overlooked, disregarded, and unenforced. It can be a revenue source for the govt entity. main purpose is to protect homeowner from poor install and to see that codes have been followed. codes do change. depending on situation, some homes might be grandfathered in while some situations will require upgrade to meet new code.

make no mistake. if you pull a permit, the cost will be absorbed by homeowner. the idea of $500 cost is absurd. you might want to check with your local building dept/inspection office.

if you are dealing with a reputable company who has a demonstrated track record, then it is probably not necessary. However if it is state law with enforcement, you can not get around it without a possible heavy fine and the dealer's license possibly being suspended or revoked.

Good Luck!

    Bookmark   November 5, 2010 at 8:42AM
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So of the Bids that I have received w/ permitted inspection:

Carrier Dual stage 58CTX110-1-16 (I think it's a 110k btu) - Warrenty 5 yrs parts and labor, 20 yr heat exhanger. Honeywell 8000 thermostat. $3147

American Standard Freedom 80 - 2 stage- . Warrenty 5 yrs parts and labor, 20 yr heat exhanger. Honeywell 8000 thermostat. $3150

Heil 100k btu (H8MPT100F14) 2 stage - Warrenty 10 yrs parts, 25 yr Heat Exchanger, 1 yr labor. Honeywell 4000 thermostat. $2,487

Any thoughts/recommendations. Don't know Heil's reputation, but does not seem at same level as Am Standart or Carrier. But $ 700 difference, and better warranty


    Bookmark   November 19, 2010 at 5:01PM
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let's see a complete mdl number for the AmStd quote.

Since you plan on using this condo on a frequent basis, I would want a good furnace. Since a 95% is out of question, I would want an 80% eff two stg furnace with a var speed blower. Yes this may cost a little more but you will be happier in the long run. Have any dealers provided a professional load calculation for correct sizing? is condo an internal unit or external unit? can't recall. were any suggestions offered by dealer on the studio room?

HW offers a relatively inexpensive air filter cabinet that I would recommend.

see link.


Here is a link that might be useful: AmStd Freedom 80 Comfort R Furnace

    Bookmark   November 19, 2010 at 5:44PM
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Here is the model numbers for the Amer Standard furnace

2 stage-----AUD2B080A9362A

The manual J heating load came up to 76,451 input btuâÂÂs needed, this furnace is 80k BTU

So looks like Thumbs down on the Heil, even though a lot cheaper and longer warrenty?


    Bookmark   November 22, 2010 at 1:40AM
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Heil is part of the ICP group of HVAC companies. mid range,good warranty.

ask dealer to provide a quote on their VS80 two stg var speed mdl furnace. see link below.

be aware that the AmStd two stg furnace quoted only has a 63K BTUs on high stg. I suggest your load calc be rechecked for correct sizing.

I do think two stg is the way to go and I prefer the var speed blower model if your budget allows. Two stg stat will be required for best operation like the 8000 series Honeywell model.

what plans did you make for the studio room?


Here is a link that might be useful: Heil VS80 furnace

    Bookmark   November 22, 2010 at 10:29AM
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Make sure you will recover any cost difference between 80% and 95%in a reasonable time ... like before the unit needs to be replaced.

In a house not used year round the higher efficiency often never pays for itself.

Also keep in mind that the higher efficiency units have more parts and a high failure rate.

Failure rate is rarely improved by making something more complicated with additional parts.

    Bookmark   November 22, 2010 at 3:29PM
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for info, OP says home/condo can not take a 95% eff furnace.

    Bookmark   November 22, 2010 at 4:11PM
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So from what I can gather, the benefit of the variable speed blower is it is quieter when on low speed, but costs significantly more. And modern furnaces are louder than the older furnaces. How much difference is the noise?

Noise may and may not be an issue. The furnace is in a closet directly next to a bedroom, but it is a guest bedroom (our freeloading friends); the kitchen is also on the same floor. Our bedroom is directly above this guest bedroom on the top floor, the living room is also on this top floor.

Also any experience with thermostats that you can control over the internet?

Thanks again, hope everyone had a great thanksgiving!!!

    Bookmark   December 3, 2010 at 8:17AM
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if I was not going two stg 80% var speed furnace which BTW is your best option, I would at least go sgl stage with the high eff blower motor. I know Trane,AS, Carrier/Bryant offers this type furnace.

yes, both are quieter than conventional blower motors and cost less to operate.


    Bookmark   December 3, 2010 at 8:46AM
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"make no mistake. if you pull a permit, the cost will be absorbed by homeowner. the idea of $500 cost is absurd. you might want to check with your local building dept/inspection office. "

$500 May not be out of line at all.

Fill out the forms, stand in line, front the permit fees.
It often takes most of a morning.

That is four hours of NOT working just to pull a permit for a single job.

It is so bad in many areas that there are companies that do nothing but the legwork for permits (for a fee of course) so that tradesmen can keep working.

    Bookmark   December 3, 2010 at 8:59PM
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So I think I had the ranking of furnace types incorrect, is this how I should rank them:

#1 - 2 Stage variable speed blower
#2 - 1 Stage High efficiency blower
#3 - 2 Stage Dual Speed Blower
#4 - 1 Stage Single speed blower


    Bookmark   December 5, 2010 at 6:08AM
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2 stage dual speed blower should be number 2.

    Bookmark   December 5, 2010 at 8:06PM
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Still researching models and price relative to noise. Trying to stay below 3K in price, but looks tough, may have to bump up the budget if go w/ Variable speed blower. Width became a slight factor, 21" is max width, and would require some adjustment of the gas line and removal of the door. Got this website from one of the salesmen comparing sounds of different furnaces, found helpful.

Thanks everyone for help

    Bookmark   December 14, 2010 at 7:28AM
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what's the holdup?

I thought you would have new furnace installed by now.

if you wait much longer, winter will be over. LOL...

go two stg var speed correctly sized. comfort and satisfaction will long be remembered over price as long as you intend to use this home. if short term, then a good basic sgl stg non var speed would be OK.

BTW, was a load calc performed and what was the BTU requirement at design temperature?


    Bookmark   December 14, 2010 at 7:50AM
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More I look into it, the more confused I get. Some recent issues that came up are the furnace has to be 21" wide or less, and 21" is gonna be tight.The manual J heating load came up to 76,451 input BTU needed from one bidder

So got a Bid for a York Affinity variable speed blower 100k btu for $3500. Rheem Variable speed blower for $3400

The Heil 100k 2 stage dual speed blower bid for $2500

Got the Carrier and American standard bids for 2 stage dual speed blowers for like $3100. Other bids I got, the people weren't too keen on getting a permit to install. Talking to people in the city permit dept, if something happens and house is destroyed, lack of a permit may void my homeowner's insurance. In addition to making sure safe for my family (my #1)

So I am leaning toward the Heil 100K 2 stage dual speed blower, it's $900-1000 less than the modulating variable speed furnances( like a 40 % difference in price). Am I making a dumb mistake putting in the Heil??? Know it's a mid range furnace, but the warranty seems to be the best (but it may be because I am gonna need it?)

In terms of noise, I have been told that the new furnaces are 2x as loud as my current 30 yo rheem. But is that at Full power/2nd stage. If the heat and blower are at their lower stage, will it be 1 x as loud as my current Rheem, which is livable, don't really notice it and we currently sleep in room next to it. How often does it go to the 2nd stage/full power? I am assuming it will mainly be on the lower setting?

Also can I add insulation to the closet the furnace is in to reduce noise, or is that a big no no.

I really appreciate all the info I have gotten here. This site has given me info that I can talk to people and get a sense when they are BS'ing me, and have the info to call them on it.

Happy Holidays

    Bookmark   December 17, 2010 at 2:21AM
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I suspect you will be in lower stage 99% of the time.

    Bookmark   December 17, 2010 at 7:18AM
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are you satisfied that a 100K 80% eff furnace is correct size? this will be for a condo? internal or external unit? bottom floor or top floor unit? has an actual load calc been performed? if so, you have seen it in writing and have a copy?

two stg 80% var speed furnace correctly sized is way to go. you must get a two stg thermostat. and I recommend a 4-5" box filter. furnace should have stainless steel heat exchanger.


    Bookmark   December 17, 2010 at 8:17AM
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