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Posted by KEN on November 12, 2008 at 08:59:19:
In Reply to: Re: Lochinvar Knight posted by HeatPro on November 11, 2008 at 21:20:45:
: The current boiler is a Laars Minitherm 185K btu spec'd a Lochinvar Knight condensing boiler. I have read on various forums that the newer condensing boilers can save 30-40% on fuel useage. If so, that might make pretty good sense.
: It would make less sense to you knowing that the AFUE rating on the old boiler was 80% and the condensing boiler can do 94%.
: 14% more isn't 30-40%, so double your payback period. Salesmen often use overinflated impressive wheeze numbers left over from 1980 when boilers were 65% AFUE and condensing boilers of today do 94%.
: Nowadays new boilers are at least 84% AFUE, so getting a condensing boiler that does 94% instead can save 10%. Salesmen need to get a new wheeze to match reality in these times.
HeatPro, Thank you for your insight. How much does altitude impact these numbers? SInce I am new to the boiler game I had not thought about the efficiency numbers as described by the AFUE test as an indicator of overall system efficiency. I appreciate your input and that will definitely impact my decision to go forward.
Does anyone have any experience with running a mod/con boiler at high altitude (10,200 feet)? I have received some input from another HVAC guy that tells me mod/cons have issues trying to work at high altitude. I don't know what those could be but would appreciate hearing from anyone that has experience.