[VitoB]

Hi everyone,

I have a Lennox G61MP 95% efficiency furnace.

It is a 2 stage furnace and the blower motor can be set to run at low speed.

Should I be setting my fan to run all the time? Right now I have it set to automatic and it only kicks in when the temperature drops for the furnace to heat.

I would think the furnace would use a lot more electricity if I let it run all the time, however the ducts would keep a more stable temperature I believe.

Curious to know what others do in their homes.

Thanks!

 

[yuri]

It has a standard PSC permanent split capacitor motor which is not a energy efficient motor like a ECM type. Uses about 500 watts of electricity to run which can cost you $1-2/ day to run depending on your elec cost. I would not run it. Some newer furnaces have ECM variable speed motors which use less elec and run slower. Some people find the "low" speed yours has to be too fast and drafty. No way to slow it down. There are some aftermarket speed controls but they are expensive and can damage the motor and I won't sell them. There was a G61MPV with the variable speed ECM motor for another $500 when they first sold that furnace. Gone now.

 

[Bob Sanders]

It depends on your situation. If you have a lot of hot and cool spots in your house then running the fan can even out the temperature. We have a sun room with 3 outside walls and it tends to cool faster than the rest of the house so I set the thermostat to run the fan during the day time when there is usually activity in there. It helps keep the temp a bit better. During the evening and night though the fan is scheduled to be off.

On the other hand if you have no real reason to be running the fan.... then why waste the money.

 

[user_12345a]

the 2-stage furnace may run the fan on the low heat speed for continuous mode, so probably closer to 300 watts.

 

[VitoB]

It has a standard PSC permanent split capacitor motor which is not a energy efficient motor like a ECM type. Uses about 500 watts of electricity to run which can cost you $1-2/ day to run depending on your elec cost. I would not run it. Some newer furnaces have ECM variable speed motors which use less elec and run slower. Some people find the "low" speed yours has to be too fast and drafty. No way to slow it down. There are some aftermarket speed controls but they are expensive and can damage the motor and I won't sell them. There was a G61MPV with the variable speed ECM motor for another $500 when they first sold that furnace. Gone now.

I wish the company that installed my furnace would have actually done a better job of explaining certain options to us.

Appreciate your advice, I will not bother with it.

I heard this in a podcast with Cliff Hoyme (I'm sure you know who he is) where they were discussing running the furnace fan continuously to keep the ducts at a more stable temperature.

Most of the joints in my ducts need to be sealed, so I guess I would be better off focusing on that to be sure the furnace itself performs better.

Thanks yuri and everyone else who replied.

 

[yuri]

Cliff Hoyme of the Hoyme auto damper co and Shell Bussey. I would trust neither with technical specific furnace advice. They hawk their products and people believe them because they sound technical and sincere.

However the bit about stable duct temp probably has to do with a open fresh air pipe (w/o Hoyme damper) bringing raw COLD -10 to -40C Canadian air in with a continuos running fan. With a Hoyme damper it only opens with a demand for heat. Probably got lost in the translation what they were talking about. Continuos circ fan is for comfort or to get air to further away problem areas and primarily if a person has a electronic air cleaner or high end filtration system they want to use.

I would seal the joints and fix any air leaks around doors or windows or your attic hatch and insulate the atttic to R40 for your best bang for yer loonie.

 

[beenthere]

the 2-stage furnace may run the fan on the low heat speed for continuous mode, so probably closer to 300 watts.

7.2KWHs a day/216KWHs a month. Now of course, it wouldn't come out to that much when you subtract the electric used when the thermostat calls for heat.

But, its a lot of electric to run the fan 24/7 even if its only 300 watts an hour.

 

[yuri]

I had a customer who had to run her fan 24 hours a day because the board got fried with the fan on and she was buying a new furnace. Not sure why it took a month to get installed ( she went away I think ) but when I started it she said her elec bill went up $30 for the month. Double that for Onatrio rates and you don't want to do it. We can split hairs about the amp draw on a PSC on low but it probably is close to 3.5 and 4 on high speed. 3.5 x 120 volts = 420 watts. $20-30 a month more for a fan is ridiculous.

 

[user_12345a]

I never recommended running the fan continuously; anyone who insists on that could use an ecm motor retrofit, drop it down to 100w or less.

actual draw will depend on the blower size, speed tap, duct pressure to a small extent with the higher pressure resulting in a lower amp draw on the psc motor.

 

[user_12345a]

primarily if a person has a electronic air cleaner or

those are going away, at least i hope.

 

[yuri]

Trane Clean Effects, Lennox Pure Air.

 

[cleveman]

I've had my fan running now for about 4 years. I plugged the furnace into an extension cord with the wires exposed and measured how much power it was pulling. I don't remember what I got, only that it was lower than my box fan on the "low" setting.

 

[VitoB]

Cliff Hoyme of the Hoyme auto damper co and Shell Bussey. I would trust neither with technical specific furnace advice. They hawk their products and people believe them because they sound technical and sincere.

However the bit about stable duct temp probably has to do with a open fresh air pipe (w/o Hoyme damper) bringing raw COLD -10 to -40C Canadian air in with a continuos running fan. With a Hoyme damper it only opens with a demand for heat. Probably got lost in the translation what they were talking about. Continuos circ fan is for comfort or to get air to further away problem areas and primarily if a person has a electronic air cleaner or high end filtration system they want to use.

I would seal the joints and fix any air leaks around doors or windows or your attic hatch and insulate the atttic to R40 for your best bang for yer loonie.

I installed a Hoyme damper last year on my fresh air pipe. I had also turned off the electronic air cleaner with your help and installed a disposable filter instead.

Thanks for pointing me in the right direction once again. :thumbsup:

 

[yuri]

Yur Welcome:wink2: