Quote:
Originally Posted by Mobile Master Tech
Energy Star's have a 67% or greater energy factor, which is probably about an 80% efficient burner.
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Gas hot water heaters loose convective heat up the stack constantly and are not nearly as efficient as advertised.
Heating requirements at high altitude in Colorado are MUCH different than Southern states.
My Son's house is in Crested Butte Colorado at 8,888' altitude, climate zone 6, as is much of Alaska (read too damn cold).
IBC 2009 states that the heating system has to be able to keep every room at 70* at design temperature (-20*F)
It was designed & specified by a great architect who used REScheck to calculate the UA = 1,194
The Design Delta between 70* -> -20* = 90*
The output of the boiler must be at least: 1,194 x 90 = 107,460 btus/hr
I decided on a Burnham ESC6NI-TH (high altitude version) Sealed combustion via side wall.
Efficiency=85.2%, DOE=130,000, IBR=113,000
A proven design cast iron boiler like this costs about 1/2 of a good ModCon boiler.
But it is way more reliable, will probably last 30-40 years, & requires MUCH less maintenance.
This is why plumbing/heating shops love ModCons, they weigh a lot less & there is way more profit $$
A large boiler needs a large buffer tank to prevent short cycling, especially if only 1 zone is calling for heat & it's 50* outside.