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Posted by The King on October 16, 2009, 9:04 pm
On Fri, 16 Oct 2009 20:18:41 -0400, .p.jm.@see_my_sig_for_address.com
wrote:
>On Fri, 16 Oct 2009 19:01:37 -0400, The King
>>On Fri, 16 Oct 2009 20:19:19 +0000, kris60660_at_yahoo_dot_com@foo.com
>>(heartmd) wrote:
>>>-------------------------------------
>>>I currently have TWO 80% 20 year old Tempstar 150K BTU furnaces, one for
>>>each floor in my 4600 sq ft home (2300 in each floor) (built in 1989).
>>>Due to some situation, the builder will be replacing both furnaces with
>>>new Trane 92% furnaces. He says that per his calculations TWO 120K BTU
>>>furnaces will be enough for my home (I am adding R30 cellulose insulation
>>>to my attic)
>>>I have to pay extra if I need TWO 95% furnaces instead and extra if I want
>>>TWO variable valve and variable speed ones (all from Trane)
>>>I use $2288 worth of gas each year to heat my hone and operate the hot
>>>water heater and drier each year.
>>>Questions:
>>>1.
>>>Am I right that I will save 3% on my gas bill with the extra 3%
>>>efficiency?
> Pretty close. Actually 2.xx something
>>>That means I will save $60 each year and for the lifetome of
>>>the 95% furnace which is 20 years, I will save $60X20=$1200 for both
>>>furnaces ($600 for each furnace). So anything more than $600 extra for
>>>each 95% furnace will not be cost effective
> What would that money get you in a CD etc for 20 years ? Your
>loss of that benefit over time adds to your investment cost now,
>realized 20 years from now.
> IOW - do you want to wait around 20 years to get your 600 $
>back, no interest ? If so, please send it to me today ;-)
>>>2.
>>>What is the gas savings with the variable valve and variable speed.
> That's more a comfort issue ( evenness of temperature ) than
>fuel cost.
>>>3.
>>>Do variable valve and speed furnaces make any sense financially and even
>>>comfortwise in a 2 furnace home?
> Judgement call.
>>You didn't say where you live but unless you live in Nome AK you are
>>probably oversized.
>120,000 doesn't seem oversized for 2,300 sq ft ( per floor )
>> What you need to do is run a manual J heat loss
>>calc on your home.
> Yes.
>> Size the furnace(s) accordingly and get the
>>highest efficiency you can afford.
> Within, as he discusses, reasonable price / payback
>calculations. Within which he forgot to adjust for the time value of
>money. $ 600 today = $ 1,800 20 years from now, etc.
> IMO, the 92 might be the better deal. lots of variables, of
>course.
Is the 5K tax rebate deal still going on? To qualify for that you
have to have 95% afue or better furnace. Like you say 3% isn't a huge
deal but to me the best way to drive prices down is try and use as
less as possible.
I try really hard at limiting my energy consumption. Insulation is
cheap, ive saved a tank and a half of LP over a years time by adding
insulation to the attic..
insulation. 300
lp savings 5-600. Its a no brainer.
It would make sense to first check and if necessary add insulation to
decrease heat loss downsizing ever further. Insulation could save the
equal amount, or nearly as much, as the 3% eff increase of a furnace.
The price difference is not that large between the two (92-95+)
anyway. Just a few hundred. Might as well get the best bang cause
the average guy is only doing this once or maybe, twice.
Lots of variables as you say.
>>Emphasis on the following. You will be decreasing the input and
>>using more of the output. Its a win win.
>>A properly sized two stage highest efficiency variable speed furnace
>>is the way to go. A two stage variable speed furnace will modulate the
>>output according to outside conditions thus minimizing input whenever
>>possible. Do the math using your personal data and see what your
>>costs compare to now. I think you'll find a much greater savings than
>>you currently anticipate.
>>Tell the mormon to piss off.
> The bitch never pays attention.
He's punch drunk.
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>I currently have TWO 80% 20 year old Tempstar 150K BTU furnaces, one for
>each floor in my 4600 sq ft home (2300 in each floor) (built in 1989).
>Due to some situation, the builder will be replacing both furnaces with
>new Trane 92% furnaces. He says that per his calculations TWO 120K BTU
>furnaces will be enough for my home (I am adding R30 cellulose insulation
>to my attic)
>I have to pay extra if I need TWO 95% furnaces instead and extra if I want
>TWO variable valve and variable speed ones (all from Trane)
>I use $2288 worth of gas each year to heat my hone and operate the hot
>water heater and drier each year.
>Questions:
>1.
>Am I right that I will save 3% on my gas bill with the extra 3%
>efficiency? That means I will save $60 each year and for the lifetome of
>the 95% furnace which is 20 years, I will save $60X20=$1200 for both
>furnaces ($600 for each furnace). So anything more than $600 extra for
>each 95% furnace will not be cost effective
>2.
>What is the gas savings with the variable valve and variable speed.
>3.
>Do variable valve and speed furnaces make any sense financially and even
>comfortwise in a 2 furnace home?