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Using Gas heater exhaust as heat source for radiant heater?

cassetti's Avatar

Join Date: Jan 2009
Posts: 2

01-25-09, 12:25 PM   #1  
Using Gas heater exhaust as heat source for radiant heater?

Hey all!

First time home-owner here. Just purchased my house in october.

My house is all natural gas - heat, water, stove and oven. It has many of the typical upgrades you'd expect to increase efficiency: extra rolled insulation in the attic, new windows throughout the house, new roof (3 years old). And i put in a digital thermostat (saved me $40 a month on my gas bill!)

Anyway, I got to thinking about my chimney exhaust for both heaters - my no-contact themometer reads around 200 degrees on the pipe leading to the chimney.

Can anyone suggest any sites that would be useful for exploring the possibility of using that heat to heat a resevoir of water used to generate radiant heat for my home?

I would like to research the possibility of reducing my heating costs by reusing this waste heat. Plus I could really use cheaper bills since i have been unable to find a roommate for the time being!

Thanks All! (btw, new poster to the forums!)

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goldstar's Avatar
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01-25-09, 01:20 PM   #2  
While I suppose something could be rigged up, even fins around the pipe would provide a little extra heat in the basement, high effeminacy furnaces and water heaters have the same end result. The furnaces extract the waste heat through a secondary heat exchanger and are 90% - 95% efficient. The exhaust heat going out the stack is so cool that plastic pipe is the new exhaust stack.


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Gunguy45's Avatar
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01-25-09, 01:32 PM   #3  
The problem I have seen mentioned with this type of thing is that if you really find a way to extract a lot of heat, you can cause problems with exhaust gas flow and condensation. The HiEff furnaces have to use drains and pumps to get rid of the water produced.

"I sometimes wonder how some people ever made it to adulthood..."

cassetti's Avatar

Join Date: Jan 2009
Posts: 2

01-25-09, 02:45 PM   #4  
I was considering the use of water in some tubing to pull the heat away from the pipes and then radiate the heat. This would allow the pipes to run cooler and allow the air to circulate up.

I am considering this option because my house is 50 years old, and the heater is just that old. (the mfg address on the heater doesn't even list the zipcode because it was before the zip code system was established!)

I would love to replace it but unfortunately I don't have excess cash laying around to install a new one. I already dropped my electricity bill a few bucks a month by installing LED bulbs throughout the house (got a nice discount on them)

Starkvegas's Avatar

Join Date: Feb 2014
Posts: 1

02-11-14, 05:52 AM   #5  
Did you ever do this?

I was having the same thoughts as you on recovery of this heat. I have a large NG furnace that vents very hot air. Was thinking about using it as source for radiant heat source for floor, or to heat crawl space, or to use as heat source to keep copper pipes in crawl space from freezing ( or all 3?).

Curious if you ever did this?

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