80% efficiency versus 95% hydronic boilers
GBA Editor
| Posted in Mechanicals on
I am trying to calculate the anticipated savings using a high efficiency
modulating condensing boiler versus a high efficiency boiler with an
80% AFUE. New home super insulated in New Jersey. At what point
will the additional $10,000 cost be recouped?
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Replies
Unless you're talking about replacing a new boiler already installed in your new home, there should be only a small difference in upfront cost between the two options, not $10,000.
The increase in efficiency is 18.75%, so that should be the approximate reduction in annual heating costs. In order to calculate annual heating savings, you'll need an annual heat loss analysis for your house and the current fuel cost for your area. If you're getting domestic hot water from the boiler as well, then you also need to project annual hot water consumption and include the savings there as well.
But, if you're looking at a $10,000 difference, your mortgage is going to be payed off before you payback your investment in the ModCon boiler, unless you're living in Bill Gate's house.
Define superinsulation in New Jersey.
I would like to install a +90% A O Smith Vertex 100 kbtu/h water heater for domestic water and to space heat thru a 2 ton fan coil with a 2 ton CAC SEER 14. This will produce about 40 mbh of space heat and provide a 40 gal hot water heater. I estimate the cost of the vertex plus mixing valve and pump would be about $2000 and the HVAC about $2500 for my modest $500 do-it-yourself insulation upgrade(R38 attic, and air leaks) minus $1500 tax credit.
If I save $350 per year off a $1000 energy bill, that's a 10 year payback.
Please comment on my scheme.
How many btuh is a $10000 boiler?
How superinsulated is a house that needs a $10000 boiler?
Doug,
You asked, "Define superinsulation in New Jersey." Good question.
I could make some New Jersey jokes — but that would be cheap and unproductive.
When discussing R-values, I consider that anyone bragging about "superinsulation" should be building a house with assembly R-values that are at least twice as high as code minimum requirements.
Anonymous,
You wrote, "If I save $350 per year off a $1000 energy bill, that's a 10 year payback." But you never told us what you are comparing your HVAC equipment to.
You evidently think that your energy bills will be $350 lower than the energy bills of a hypothetical house that you don't identify. So your boast doesn't mean much.