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160F as a design temerature with standard efficiency boiler

Vad Member Posts: 55
 Is this acceptable to use 160F as a design temperature with Standard efficiency boiler that have 140F as minimum return temperature (Burnham Series 2)? Setting 160F on Standard efficiency boiler will I get more energy efficient system?

 I am thinking on using ModCon boiler but still there is a chance that I will be using standard efficiency one. I need to calculate baseboard size and install it  prior to selecting the boiler. I realize that it is not the really right way of building the system.

 If I understand right, it make sence to make the design temperature 160F for use with high efficiency boiler.

I appreciate you input.

Thank you,



  • Gordan
    Gordan Member Posts: 891
    Here's why

    A boiler running on outdoor reset will only reach its design temperature a very small portion of the heating season. If that design temperature is outside of the condensing range (160) then you wouldn't reap the benefits that a mod-con boiler provides during that small portion of the heating season, but that's OK, because you'd still be reaping the benefits during the bulk of the heating season.

    Using 160 as your design supply temperature allows you to size your emitters (radiators or baseboard) smaller than if you were using, say, 120 as your design supply temperature. This saves money up front, and doesn't give up much in the way of fuel savings. Beyond that, there are diminishing returns.

    A non-condensing boiler may be theoretically a teensy bit more efficient with lower supply temperatures, but this is negligible and it definitely doesn't ever result in payback on the extra cost you spent on your emitters to bring the design temperature lower. Stop mincing already and go for condensing. :-)
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