Furnace fan controller - Page 2

chadb · 01-02-13, 12:21 PM

Yep, thermostat is in the living room. It's working ok until I can get around to a differential. Got down to 17F last night. Good thing I moved the hide-a-bed couch out by the stove. I slept there and threw some firewood into the stove anytime I woke up to a chill. Thermostat is set to 67 when I'm home 62 when I'm sleeping and 60 when I'm gone. The fan is cycling on and off instead of running full time. You'd think I had a regular furnace going if you walked in. I'm worried that it may be quite cold when I get home tonight. I've been making plans on how to move more/hotter air. Right now I have about 84 degrees going in the return and 73 coming out in the living room. I'll add some information here when I start building the differential thermostat. I may put multiple units placed strategically through the house if it doesn't prove too difficult.

Daox · 01-02-13, 12:42 PM

Sounds interesting. I'm anxious to see how it turns out. I have a similar problem in my house that I've semi-fixed, but its not ideal. I have a furnace vent blowing through one room into another since there are no vents in there. The temperature swing in that room is quite large due to many windows.

opiesche · 01-03-13, 05:25 PM

Coming back to what you mentioned about insulation:
What sort of insulation do you have in your house? If you don't have a big budget but enough time, buying $150 worth of drywall and fiberglass insulation (about a room's worth) could be the biggest bang for the buck you can get, if the exterior walls aren't insulated at all (which is not uncommon in old houses).

Ripping out the exterior walls' drywall (or lathe and plaster, depending on your house), installing fiberglass, and putting in new drywall is something that 2 people can do in a weekend for a single room. You could do one room at a time this way, spread out the expense and job scope over time and gradually improve comfort and energy bills - that's of course assuming that installing insulation is all you need and don't have to worry about replacing exterior siding or installing additional moisture barriers, etc.

opiesche · 01-03-13, 05:43 PM

Something else to consider: if you just want to move the warm air from one end of the house to the other, have you considered using smaller, more power efficient quiet fans?

Reason I'm asking is, I've got a really noisy and power hungry exhaust blower in one of my bathrooms I'm considering replacing with a couple of these:

Newegg.com - MASSCOOL FD12025S1L3/4 120mm Case Cooling Fan

52 cubic feet per minute at 25db sounds pretty good to me (a normal bathroom exhaust fan doesn't do more than 100CFM either), and these usually run at or around 1W compared to the 40W a regular bathroom blower uses.
The question is just whether it would be able to build enough pressure to move the air through the duct...

Daox · 01-04-13, 09:23 AM

Do you have any idea how much less the fan is running now? Is it 50% of the time, 25%? I'm curious about the power savings this has shown.

chadb · 01-04-13, 05:51 PM

I have to come up with a way to measure the time the fan spends running now. I also need to get a meter and find out how much power it actually pulls. It seems like the fan is running 50% of the time when I'm home and the stove is burning good. I have a feeling it runs quite a bit while I'm away. I'll try to find a cheap way to measure it. Maybe I can pick something up at lowes tomorrow.

Daox · 01-05-13, 06:30 PM

I believe most furnaces run on 110V. A killawatt should be able to do the trick for how much power its pulling. Run time is more of a thing where you'd have to log on/off time. I don't know of a device that will do this automatically.

01-02-13, 12:42 PM	#12
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Sounds interesting. I'm anxious to see how it turns out. I have a similar problem in my house that I've semi-fixed, but its not ideal. I have a furnace vent blowing through one room into another since there are no vents in there. The temperature swing in that room is quite large due to many windows. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

01-04-13, 09:23 AM	#15
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Do you have any idea how much less the fan is running now? Is it 50% of the time, 25%? I'm curious about the power savings this has shown. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

01-05-13, 06:30 PM	#17
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	I believe most furnaces run on 110V. A killawatt should be able to do the trick for how much power its pulling. Run time is more of a thing where you'd have to log on/off time. I don't know of a device that will do this automatically. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

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01-02-13, 12:21 PM	#11
chadb Lurking Renovator Join Date: Nov 2012 Location: Mt. Orab, OH Posts: 18 Thanks: 3 Thanked 0 Times in 0 Posts	Yep, thermostat is in the living room. It's working ok until I can get around to a differential. Got down to 17F last night. Good thing I moved the hide-a-bed couch out by the stove. I slept there and threw some firewood into the stove anytime I woke up to a chill. Thermostat is set to 67 when I'm home 62 when I'm sleeping and 60 when I'm gone. The fan is cycling on and off instead of running full time. You'd think I had a regular furnace going if you walked in. I'm worried that it may be quite cold when I get home tonight. I've been making plans on how to move more/hotter air. Right now I have about 84 degrees going in the return and 73 coming out in the living room. I'll add some information here when I start building the differential thermostat. I may put multiple units placed strategically through the house if it doesn't prove too difficult.

01-03-13, 05:25 PM	#13
opiesche Helper EcoRenovator Join Date: Jul 2012 Location: Rohnert Park, CA Posts: 99 Thanks: 4 Thanked 14 Times in 9 Posts	Coming back to what you mentioned about insulation: What sort of insulation do you have in your house? If you don't have a big budget but enough time, buying $150 worth of drywall and fiberglass insulation (about a room's worth) could be the biggest bang for the buck you can get, if the exterior walls aren't insulated at all (which is not uncommon in old houses). Ripping out the exterior walls' drywall (or lathe and plaster, depending on your house), installing fiberglass, and putting in new drywall is something that 2 people can do in a weekend for a single room. You could do one room at a time this way, spread out the expense and job scope over time and gradually improve comfort and energy bills - that's of course assuming that installing insulation is all you need and don't have to worry about replacing exterior siding or installing additional moisture barriers, etc.

01-03-13, 05:43 PM	#14
opiesche Helper EcoRenovator Join Date: Jul 2012 Location: Rohnert Park, CA Posts: 99 Thanks: 4 Thanked 14 Times in 9 Posts	Something else to consider: if you just want to move the warm air from one end of the house to the other, have you considered using smaller, more power efficient quiet fans? Reason I'm asking is, I've got a really noisy and power hungry exhaust blower in one of my bathrooms I'm considering replacing with a couple of these: Newegg.com - MASSCOOL FD12025S1L3/4 120mm Case Cooling Fan 52 cubic feet per minute at 25db sounds pretty good to me (a normal bathroom exhaust fan doesn't do more than 100CFM either), and these usually run at or around 1W compared to the 40W a regular bathroom blower uses. The question is just whether it would be able to build enough pressure to move the air through the duct...

01-04-13, 05:51 PM	#16
chadb Lurking Renovator Join Date: Nov 2012 Location: Mt. Orab, OH Posts: 18 Thanks: 3 Thanked 0 Times in 0 Posts	I have to come up with a way to measure the time the fan spends running now. I also need to get a meter and find out how much power it actually pulls. It seems like the fan is running 50% of the time when I'm home and the stove is burning good. I have a feeling it runs quite a bit while I'm away. I'll try to find a cheap way to measure it. Maybe I can pick something up at lowes tomorrow.