reduce speed of furnace recirculation fan

[alanaround]

Has anyone modified their furnace fan so that it has multiple speed settings? Basically, I have a developed basement and generally it's fine, but always cooler. It's at its coldest when the outside temperature is between ~5 and -5 because then the main floor maintains the temperature well enough that the furnace doesn't kick in. I like the idea of running the re-circulation fan constantly or on a timer, as it helps with the movement of air, except for whatever reason, this home (2010 build) is the noisiest system I've come across so I was wondered about trying to run the fan at 50% lower...

any thoughts? Is this possible? If I run the recirc and then the furnace actually kicks in, I don't hear a change in speed or anything, just the furnace coming on.

[ExtraSlow]

This sounds like a great idea, I'd like this info as well.

[Tik-Tok]

Check the motor itself. When I was going to do the same thing, I found my furnace blower was a 4-speed, and the system only utilizing one wire (high speed). So I used the medium-high for when the furnace was on, and then wired a relay so low speed is continually running, but wired to a switch located near my thermostat.

Keeps the entire house a nice even temperature, and only costs $20 a month for electricity, which is worth it to me.

If it's not a multi-speed blower, I suggest replacing it with one.

Edit: Note, this is for old school AC blowers, I have no idea about newer DC blowers.

[Thaco]

Yeah i have replaced my blower motor a couple times, even if its a single speed furnace if the motor has been replaced in like the last 10 years its likely to have multi speed, usually 3 speed, it'll have 4 wires, black is ground, and 3 other wires for each speed, should be easy enough to wire up a switch or relay or both as tik-tok mentioned to use a lower speed for re-circ, but this will also likely reduce the life of the motor because it'll be running all the time.

[Tik-Tok]

Originally posted by Thaco
but this will also likely reduce the life of the motor because it'll be running all the time.

I was thinking about that when I was first wiring it up, and my conclusion was that it will increase the life, or at least be the same, because there is no longer a "start-up" cycle which hurts the motor more than anything.

[Seth1968]

Originally posted by Tik-Tok


I was thinking about that when I was first wiring it up, and my thinking was that it will increase the life, or at least be the same, because there is no longer a "start-up" cycle which hurts the motor more than anything.

That seems correct to me.

It's similar to a light bulb or any other electrical device. It's rare that a light bulb burns out when it's on. It always happens at the initial shock and wear of "start up".

[alanaround]

nice, thanks for the info - Furnace was new in 2010 so maybe they just wired it for high or something. I'll take a look :thumbsup: