On Sat, 21 Dec 2013 14:02:50 -0500, wrote:

On Sat, 21 Dec 2013 11:28:48 -0500, micky
wrote:

On Thu, 19 Dec 2013 23:37:46 -0500, wrote:

On Thu, 19 Dec 2013 22:32:10 -0500, micky
wrote:

On Thu, 19 Dec 2013 22:22:00 -0500, Ed Pawlowski wrote:

On 12/19/2013 2:17 AM, gregz wrote:
Today's furnace specify btu. Is that input or output ?

Greg


Input. Figure the output by multiplying by the efficienct rating.

Is that true for oil furnace, too?

Yes.

Or maybe the question is, Was that true for oil furnaces 35 years ago,
too?

Yes. It was stated as such, on mine. As others have stated, it can't
be anything else. There are too many variables to state the heat
output.

Well, my furnace is a Carrier model 58HV085

And in the owners manual, it says
Ratings, Input (1000 Btuh) 106
Output (1000Btuh) 85

So it not only rates the output, it named the model of furnace after
the output.

I went shopping for a new oil furnace, but the brochures they gave me
didn't show if they rate them by input or output or both now, of if
the model number reflects either number.

(HV means it's an upflow furnace, and 58 is the series, a group of
furnaces including downflow, upflow, loboy, etc of variious sizes, a
total of 18 models, all of which are named after their rated output)

Plus the blueprints for the house, which I got fromt he architect,
have 85,000 (or maybe 85,000 btu) hand-written in big numbers at an
agle on them.


It was installed 34 years and a few months ago, and when shopping for
a new furnace, I have to be careful NOT to buy one with 85,000 input,
which won't give as much output as I have now.


Here's the spec sheet for all of them. The info starts at page 3.
http://www.xpedio.carrier.com/idc/gr...it/58h-5si.pdf

Even Carrier can't repeal the laws of physics. The only thing they
have control over is the input (and that, only to the degree that
specifications are followed). The output (efficiency) is left to age
and those maintaining the system.

True, but nonetheless, that's how this 34 year old oil furnace was
rated, and named. I guess they changed but I don't know when.

Hmmm. Have they changed that much?
I see that currently Carrier names its gas furnaces by the maximum
effficiency they can deliver, Comfort 80, Comfort 92, and Comfort 95,
model names for 80, 92, 95% efficiency. and it's probably no
coincidence that model 59SC5, ending in 5, iis the one that they say
is up to 95% efficient. And 59SC2, ending in 2, is the one they say
is up to 92%.

Not all of them are exaclly like that. Performance 90 (not 92) goes
up to 92.1% they say, but its model number is 59SP2, ending in 2. to
represent 92%. .
http://www.carrier.com/homecomfort/e...ling/furnaces/

And in oil furnaces, Performance 80 ranges they say gp from 85.7 to
86.6% eff. but they are all called Perf. *80*. The model numbers have
no numbers, only letters.

I havent' found the btu ratings, but I wouldn't be surprised if they
have a rating for output, despite its dependance on age and
maintenance. They'll say they're just rating it when it's new.