vent dampers

Jens Sorensen

Just a quick question: what kind of energy savings can you expect from a vent damper on a natural-draft boiler? Thanks.

[Deleted User]

Oil

or Gas?

Jens Sorensen

It is natural gas.

Steamhead

Depending on the boiler

the saving can be as much as 10% (AFUE)under normal circumstances. If the building has one of those old chimneys designed for coal boilers, with a draft that can almost pull you up the flue, you will probably save more.

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Boilerpro_2

On some older Peerles boiler literature....

> the saving can be as much as 10% (AFUE)under

> normal circumstances. If the building has one of

> those old chimneys designed for coal boilers,

> with a draft that can almost pull you up the

> flue, you will probably save more.

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 157&Step=30"_To Learn More About This Contractor,

> Click Here to Visit Their Ad in "Find A

> Contractor"_/A_

Boilerpro_2

Have seen the same number in..

> the saving can be as much as 10% (AFUE)under

> normal circumstances. If the building has one of

> those old chimneys designed for coal boilers,

> with a draft that can almost pull you up the

> flue, you will probably save more.

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 157&Step=30"_To Learn More About This Contractor,

> Click Here to Visit Their Ad in "Find A

> Contractor"_/A_

Boilerpro_2

Have seen the same number in..

Some older Peerless boiler literature when stack dampers were opetional. The AFUE jumped about 8 to 10% with the stack damper option.

Boilerpro

Unknown

Tests run by AGA

American Gas Association back in the 80's and early 90's reported 3 to 5 % savings. You can not use vent dampers on any converted appliances. All conversion burner manufacturers warn against it and the code prevents it.

If it is part of the package it is there with a standing pilot 24 volt system most of the time. The purpose is to get an acceptable AFUE rating on the equipment. They can not be used with Integrated Controls on boilers or furnaces.

I had one on some equipment I was testing for two years. We did an gas meter hookup directly to the equipment. We removed it after two years and ran the equipment with out the damper for two years. We did a degree day analysis on the four pieces of equipment along with several combustion tests periodically. Findings after four years of testing the vent damper did not save anything. The cubic foot usage was no different with or without based on degree day analysis.

During those same tests the number one action that created savings was adding insulation (blown into walls and 6 more inches added in attics). Savings of 10 to 12%.

Jens Sorensen

Thanks for the help

Mike Kusiak

Lab testing - your mileage may vary !

Again, remember that these savings are measured under ideal controlled laboratory conditions. The increase in efficiency assumes that all of the residual heat in the boiler goes into the heated portion of the house. What if the boiler is located in an unheated basement with lots of outside air for venting? When the damper closes, the boiler heat goes into the unheated basement. What happens when its a cold start system that sits cold most of the time? Under real world conditions, I dont think the savings are anywhere near what they measure in the lab. I wonder if anyone has seen a fuel usage difference after replacing a non functional damper?