Are woodstove blowers efficient?

[Starbrightsteve]

Has anyone put a watt meter on their woodstove blower?

 

[Easy Livin’ 3000]

Has anyone put a watt meter on their woodstove blower?

Good question. I've thought a little about trying to find a DC motor for my blower, as I understand that would be more efficient, and easier to run with a battery in the event of an outage.

 

[SidecarFlip]

If it's a shaded pole (induction) motor, it's not very efficient but it's simple.

 

[EatenByLimestone]

If the inefficiency in the motor results in heat, in a blower, on a woodstove, is it really inefficient? Or is it really efficient electric heating?

 

[SidecarFlip]

Don't see where a small motor (even if it's a hot small motor) could make much usable heat....

 

[thrifty]

Has anyone put a watt meter on their woodstove blower?

The original blower that came with my nightwatch insert was a shaded pole design rated at 150 watts that fit neatly under the ash lip. It also was too loud and moved too little air. I switched to a salvaged carrier wall a/c chassis with a psc type motor ducted to the insert. 115 watts and quieter. I estimate the cfm at 180 on med. speed by comparing the flow to a blower of known output.

 

[Easy Livin’ 3000]

The original blower that came with my nightwatch insert was a shaded pole design rated at 150 watts that fit neatly under the ash lip. It also was too loud and moved too little air. I switched to a salvaged carrier wall a/c chassis with a psc type motor ducted to the insert. 115 watts and quieter. I estimate the cfm at 180 on med. speed by comparing the flow to a blower of known output.

Did you keep the "new" blower in the same place and configuration as the original, under the ash lip, or is it ducted some other way?

 

[thrifty]

Did you keep the "new" blower in the same place and configuration as the original, under the ash lip, or is it ducted some other way?

The new blower is still mounted in the a/c chassis which I wrapped in oak plywood. It's bigger than the insert so it had to be placed off to the left side with rectangular steel duct connecting it under the ash lip. I have found that a larger blower wheel turning slower can produce more cfm with less noise than a smaller blower wheel turning faster. Also I have to correct my previous blower wattage figures. I read the motor labels and multiplied 115volts x 1.3 amps to get 150watts and 230v x .5a = 115w. That is not correct, sorry about that. Motors need to have power factor considered when calculating wattage . A borrowed watt meter measured the 115v nightwatch motor to be only 75w The new motor is 230 v so I can't connect it to the watt meter to take a reading unfortunately.

 

[Easy Livin’ 3000]

The new blower is still mounted in the a/c chassis which I wrapped in oak plywood. It's bigger than the insert so it had to be placed off to the left side with rectangular steel duct connecting it under the ash lip. I have found that a larger blower wheel turning slower can produce more cfm with less noise than a smaller blower wheel turning faster. Also I have to correct my previous blower wattage figures. I read the motor labels and multiplied 115volts x 1.3 amps to get 150watts and 230v x .5a = 115w. That is not correct, sorry about that. Motors need to have power factor considered when calculating wattage . A borrowed watt meter measured the 115v nightwatch motor to be only 75w The new motor is 230 v so I can't connect it to the watt meter to take a reading unfortunately.

Thanks, I think I have a good idea of what you have.

I'd like to replace mine with a DC motor, but will probably just leave it alone unless it conks out.

 

[ABMax24]

Mine pulls 80 watts on high.

It's better than running my furnace, my furnace pulls 700 watts when it kicks in intermittently, on average I use less electricity with the stove blower running 24/7 versus using the furnace for heat. Not to mention the natural gas I save not running the furnace.