Before you even get a quote to replace a boiler!

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Old 09-24-08, 02:29 AM
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Before you even get a quote to replace a boiler!

99% of boilers are oversized and almost that number are vastly oversized.

1. Don't assume that the old boiler was the proper size.

2. Don't assume that the contractor can just look at your house and know.

3. Don't assume that the contractor cares about sizing it properly. Only the best do and they are way too rare and should charge to do you a quote since it will take a few hours of their time which costs way more than your spare time.

4. Don't assume that a bigger boiler is better for your house or doesn't have to work as hard. Wrong!!!

5. Don't assume that you are helpless to know what size you need.


The heatloss calculation is definitely something that you can do yourself.

The best investment you can make when replacing your boiler is a the couple of hours it takes to do a heatloss calculation and anyone can do one it. It just takes time. The 3 or more contractors you call over will not invest 2 hours to do one for you for nothing, nor should they. They'll often sell you the same sized boiler as you have, which is already oversized... I can guarantee you that it is, or worse yet, the next BIGGEST size, or even bigger.

Our homes leak heat at different rates depending on outside air temperature, wind infiltration, etc. The boiler starts and stops to replace that heat that leaks out. If the boiler is too big, it starts and stops much more frequently and that hurts its efficiency and shortens its life. It also reduces your comfort by heating the house TOO fast.

Imagine driving a car with an on/off switch instead of a gas pedal. Would you want an engine that can just get you up to speed or do you want to have to frequently flick it on and off? That's how (non-modulating) boilers work. Even modulating boilers work that way when the boiler's minimum output is greater than the rate of heatloss.

Do the heatloss first. Don't let anyone sell you a bigger boiler than you need.

A properly sized boiler means a more comfortable house, a longer lasting boiler and will use less fuel. Smaller boilers also cost less.
 
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Old 09-24-08, 06:53 AM
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Amen brother! I see it everyday as do all of you. Proper sizing of all heating and cooling equipment is crucial. For more info see this website page FAQ
http://www.comfort-calc.net/faq.html
Lot's of questions answered about heat losses.
 
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Old 09-24-08, 08:40 PM
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Thumbs up Well put, Who

I see it all the time from "professionals" & homeowners who think bigger is better. Bigger is better for the contractor (more profit), for the wholesaler (again, more profit), & for the energy company (yep, you guessed it, more profit), but worse for the poor sucker who is footing the bill, the homeowner.

I'll add an amen to rbeck's.
 
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Old 09-26-08, 02:41 PM
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Agreed Grady. I saw a report one time from i believe Patterson Kelly boilers. they claim you can loose up to 40% of your AFUE by oversizing the boiler.
 
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Old 09-26-08, 02:45 PM
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Make it a 'sticky'

How does one go about nominating a thread as a 'sticky' ?

This should go up there on top.
 
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Old 09-30-08, 11:54 AM
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Originally Posted by rbeck View Post
Amen brother! I see it everyday as do all of you. Proper sizing of all heating and cooling equipment is crucial. For more info see this website page FAQ
http://www.comfort-calc.net/faq.html
Lot's of questions answered about heat losses.
is their calculation of heat loss (http://www.comfort-calc.net/price.html)

the same thing as the slantfin program?
 
 

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