Need your feedback on idea to save heat

I would like to capture some of the heat I loose up my chimney. Currently I have a 10 inch diameter steel flu pipe from my hot water boiler to my chimney. It is about a 4 foot run from the boiler to the chimney. When the stoker is firing, this pipe gets extremely hot. I am thinking about positioning a small fan that would blow across this flu pipe and blow some of this heat into my basement instead of going up the chimney. Any comments on this idea would be appreciated.

Hello Motor, If your boiler is an old instalation, one concern is if you have any asbestos wrapped pipes in the basement, you don't want to circulate air around and stirr up any asbestos dust. Otherwise, it certainly won't hurt to circulate some air over the flue pipe. I don't know how much heat you will recover, probably not all that much.

However if you want to reclaim more heat, then you will have to increase the surface area of the flue pipe. You need to find something that when wrapped around the pipe will conduct heat [metal of some kind] and have a raised fin standing out from the flue pipe for the fan to pick up the heat. Sort of like finned tubing for hot water-baseboard heat systems

I've been thinking about what you could use, and the only item that comes to mind is the metal angle that is used to form the outside corner on Drywall [sheetrock] jobs. You could take metal shears [tin-snips] and make cuts about every inch on one side of the angle and this would allow you to wrap the solid side around the flue, secure it with a sheetmetal screw.

If you do try this, please be carefull, that piece of thin steel angle with all the cuts in it is going to be like a hand made barbed wire or Concertina wire. And when you go to wrap it around the flue pipe it will be like wrestling with a porcupine!! Get help to wrap it around the flue.

Hope this helps, Greg L

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There are such things as heat reclaimers, which for wood are worthless because of lowered stack temps they will plug with creasote. With coal they would be what you are looking for. They have a thermostat that kicks on at a certain time, which turns on a fan to circulate the heat from the flue pipe. Go to and search engine and type in Magic Heat Reclaimer. I dont think they go to 10", but check it out.

Thanks LsFarm and laynes69.

Google search brings up a cost of about $140 for the 6in. unit. Considering it would only be economical to be running it when the pipe reaches x temperature you'd have to run that thing for many years to recover $140 worth of heat.

I would watch how much heat you try to remove from your flue pipe,a warm flue pipe and warm chimney help to create draft.If you cool down down your flue too much you could loose draft and get gases in the house.I would monitor your flue temps with a surface temp gauge while attempting this to see how it reacts,good luck!

tstove wrote:I would watch how much heat you try to remove from your flue pipe,a warm flue pipe and warm chimney help to create draft.If you cool down down your flue too much you could loose draft and get gases in the house.I would monitor your flue temps with a surface temp gauge while attempting this to see how it reacts,good luck!

hello tstove do you still have your model 320 I have a model 322 tennesee stove works. I seen you photos my 322 is almost the same except I have damper on the top with a rod hook that opens & close it a tube that goes down inside of firepot and a round one on back of pipe to damp it down nothing on door it will burn 12 to 16 hr when filled up to line inside on the plate that hangs down from top on the inside of front door the temp on stack runs at 350 to 550 f. when it is cooking and you can cook on it the top has a door that you pull up and there is a round hot plate i was told that they where made in the 20tis 30tis 40tis not sure i cant find any info on them if you found any let me know p.m. if you would like talk to you later.

You might want to check your local chain home improvement store. I've seen the Magic Heat Reclaimer by the duct work and flue pipe for about $150.

My local store has been clearing out winter items, making room for spring items. You might get lucky and pay a lot less.

to re-iterate what tsstove said,you have to be careful of cooling the stack temps too much...i thought i had a bright idea,tried it on a day off so i could monitor the change...i put i pedestal fan in the corner of my basement,behind the stove to move more heat(i thought) towards the stairwell and up to my kitchen...after about...30-45mins the warm air behind the stove turned to cooler air...then i noticed my stack temps dropped a whole...100 degrees. my stack thermometer is 12" above the elbow exiting the stove...i find my best heat output is when this reads 300 degrees...i have 2 90 degree elbows then another 90 at the s/s flue up the chimney.so...with that said..i find it alot better in my set-up to try and draw the heat with a fan...rather than push it...i hope this helps ya some.