[Greenbuilding] boiler

[Peter Kidd]

If that's AFUE, 94% for a boiler is sealed combustion. 84% is certainly
no slouch either, surprised it's as open as you suggest. What
temperature is your load, as to get 94% (even in ideal conditions)
requires almost certainly condensing, so not old cast iron radiators. 15
years isn't particularly old for a boiler, still a lot of sunk value,
and you are actually talking about replacing a boiler and a water
heater, with one unit? Your water heater efficiency is likely much
lower, and there can be issues with your existing chimney if you take
the boiler off and leave the water heater. 

In round numbers the improvement going from 84 to 94% is about 11%
reduction for the same load. Boilers aren't cheap. Your actual
efficiency of the existing and any future boiler can vary from the
"ideal" case, but that should give you some idea of what your return on
investment will be, at least in terms of purchased fuel.    


-----Original Message-----
From: Norbert Senf <norbert.senf at gmail.com>
Reply-to: Green Building <greenbuilding at lists.bioenergylists.org>
To: Green Building <greenbuilding at lists.bioenergylists.org>
Subject: Re: [Greenbuilding] boiler
Date: Tue, 21 Jan 2014 00:30:20 -0500

The 84% and 94% values represent laboratory tests done under ideal,
standardized conditions. They certainly do not reflect any of the
peculiarities of the installation, such as standby losses up the chimney
during the off cycle.


Why not get a boiler that allows you to hook up an outside air duct
directly to the boiler, rather than having to use the boiler room, by
making the boiler room literally "outside". If it is making your kitchen
cold, then it is the first thing you want to
improve...............Norbert



On Mon, Jan 20, 2014 at 10:32 PM, Benjamin Pratt
<benjamin.g.pratt at gmail.com> wrote: 

        Maybe not the best question to ask here, but can't find a better
        option:
        
        I have a 15yo 50kbtu boiler, that works fine. It is rated at
        something like 84% efficiency. There is no damper--it is always
        open. There is also a cold air inlet in the room that is always
        open. 
        
        The boiler is getting old, and the chimney it, and the water
        heater vents out of is in need of repair. 
        If I upgrade to a boiler and water heater that vents out of the
        side of the house, I will I save a lot of energy? If a newer
        boiler is rated at 94 percent efficiency, does that include the
        inefficiency off all the cold air being dumped into the house,
        and all the warm air escaping out of the chimney? 
        
        
        I am hoping the upgrade also will allow me to eliminate the
        chimney (at least to the roof line), save heating costs, and,
        hopefully, keep the furnace room warmer--indirectly heating the
        kitchen above (which is the coldest room in the house). 
        
        
        There is a local person who will sell you a boiler--even a used
        one-- and be a resource for you to do a self-install. I believe,
        if I go through this guy, that I can do a good job installing
        it.
        
        
        WIll the upgrade do what I want it to and does it make sense
        from an energy saving/economic standpoint?
        
        
        
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-- 
Norbert Senf
Masonry Stove Builders
25 Brouse Road, RR 5
Shawville Québec J0X 2Y0
819.647.5092
www.heatkit.com 

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