HVAC fan

[handsplitter]

I am relatively new to the website and have much to learn. I have several questions and will keep each of them in its own thread.

Do you guys normally operate your house's HVAC heater while you operate your woodstove? Obviously it depends if you are in Alaska or or Mississippi and what you're trying to achieve , time of year, size of your house, etc.
Here's my situation and the reason I ask:
I have always been able to heat my entire house with the wood stove alone, never turning the HVAC's heater on. The HVAC unit allows the HVAC "Fan" to run in automatic mode ( the fan only runs when the HVAC is running), or, the fan can run in "Fan" mode (meaning the fan runs continuously regardless if HVAC is running or not).
When it is super cold, it would be a little more comfortable if some of the areas distant from the woodstove for a little warmer, not a big deal, but I was wondering about running my HVAC's fan-only, to see what that does. My guess is it would make those few distant colder areas more comfortable. Also I could turn the heat on on my HVAC system, but I would like to try the fan-only mode if that will suffice; and part of the other issue is that the thermostat is probably 15-20 feet from the woodstove, those distant colder areas are upstairs. I do run 2 ceiling fans one on each level of the house. FWIW my HVAC system has 2 intake/supply registers, one on each level, the one intake register on the lower level is about 25 feet from the woodstove and in a hallway and so has a wall between the wood stove and the register, my cracked open window to allow inside air is about 7 feet from the woodstove and there are other windows cracked open for outside air.
What have you guys found about running your HVAC system at the same time as a woodstove? All comments appreciated.

 

[jetsam]

Dig a box fan out of the closet and put it on the floor at the top of the stairs blowing down towards the stove, then check your upstairs temperatures again in a few hours. It depends on the layout of your house, but lots of people have had luck with the humble floorfan.

The underlying idea is that the coldest air on the top level is on the floor, and cold dense air flows and goes where you point it much better than hot excited air does. Push that cold stuff down to the stove and the hot stuff from the stove room will fill the vacuum naturally.

 

[PaulOinMA]

The salesman at mentioned running the HVAC fan, if I want to move air around. I haven't yet since I am using the insert to heat the den and kitchen area at night. I shut the French doors to the dining room so they are just open a crack for the cats. The downstairs thermostat is in the dining room, and I noticed that the furnace kicked on last night when I was in the den. It's set for 65 for the evening. It was blowing air that seemed cold compared to how warm it was in the den.

 

[Woody Stover]

I noticed that the furnace kicked on last night when I was in the den. It's set for 65 for the evening. It was blowing air that seemed cold compared to how warm it was in the den.

They say you lose a lot of heat to the ducting. I would try small floor fans first (8",) to move heat.

 

[blades]

Unless your ducting is insulated it generally won't help. typical construction is main duct lines in basement return and hot. ever notice when your furnace first turns on the initial air flow is cold until all that hot duct is warmed up. Even then likely losing a third or more temp to the temp in the basement in its travel to other parts of the house.

 

[handsplitter]

They say you lose a lot of heat to the ducting. I would try small floor fans first (8",) to move heat.

Thanks guys. Last season I did use an 8 inch floor fan at the BOTTOM of the stairs to push the warmer lower level air up.
All my duct work is inside the house except maybe 4 ft is in the attic .

I will try all 3 ways
- my HVAC fan & see how fast it happens,
- the box fan at the top of the stairs (not practical long term but leaning) &
- will try the smaller 8-inch fan (more practical) at the TOP of the stairs

 

[jetsam]

Thanks guys. Last season I did use an 8 inch floor fan at the BOTTOM of the stairs to push the warmer lower level air up.
All my duct work is inside the house except maybe 4 ft is in the attic .

I will try all 3 ways
- my HVAC fan & see how fast it happens,
- the box fan at the top of the stairs (not practical long term but leaning) &
- will try the smaller 8-inch fan (more practical) at the TOP of the stairs

I personally use a small fan only on the coldest few days of the year, and it is more than enough. I have a pretty open layout though. The box fan may be better for a less open space.

 

[wooduser]

It's true that heat losses from ductwork are significant, especially when starting them and they need to be warmed up.

But nothing can warm up remote parts of the house like central heating, and perhaps even a central heating fan.

Where is the return air duct?

Mine is on the floor in the living room where the stove is located, so it's sucking up the coldest air in the room, at least initially. But if I operated it for a while, those stratified temperature layers would be broken up and it might be sucking in warmer air. If I were doing that a lot, I might consider adding some ductwork to the return air vent on the floor so it would be sucking in return air from near the ceiling.

Even if the air exhausted coming out of the "warm" air vents still feels cool, I';ll bet it would help warm up those remote parts of the house ----some.

It will also of course cool down the parts of the house you currently heat, in order to provide heat elsewhere. No free lunch!

I'd try it and see what happens!.

I'd be interested to hear what your experience is.

 

[vwmike]

I have 2 bedrooms over my garage that face east which in the dead of winter is our prevailing wind direction. When it's bitter cold I will run my hvac fan to help even out the temps. IT works fairly well but dont expect quick results, mine has to run about twelve hrs to make a noticble difference. My stove is heating from the basement and the ducting is in the ceiling so I don't have the cold duct effect.

Another factor is how old your equipment is. Mine is old so has a motor and a belt, they aren't efficient at all, if you have a newer direct drive blower they are much better.

 

[Rainey_inWA]

I just joined the site today and am having a similar issue with heat distribution. My husband and I just designed and built our home in Eastern Washington, it's approximately 2800 sq.ft. (half main floor and half full, walk-out basement). The full basement was a bit of a last minute design change as it was initially intended to be a partial basement and more mechanical than living space. Anyway, our wood stove is centrally located on the main floor which has a great room with a vaulted ceiling and a huge ceiling fan. The stairs to the basement are also centrally located directly next to the stove. All of our duct work is captured in the floor joists (aka basement ceiling), and the basement is completely finished. We just started using the wood stove this past week (Quadra-Fire 3100) and it will absolutely toast your buns (>90 degrees) upstairs but the basement dropped to approx 60 degrees. (I'm kicking myself with the obvious design flaw now.) There is an air return in the floor right next to the stove and another in the adjacent room, plus one "centrally located" in the basement.
Since hot air rises, any suggestions on the best way to push it down the stairs and into the basement? Thanks in advance

 

[begreen]

Yes, warm air wants to go up, not down. In new construction did they insulate all ductwork> Have you tried running the hvac blower to see if it raises the basement temps? It may seem radical, but have you thought about moving the stove directly below where it is by running chimney pipe all the way down to the basement ceiling?

 

[Rainey_inWA]

Yes, warm air wants to go up, not down. In new construction did they insulate all ductwork> Have you tried running the hvac blower to see if it raises the basement temps? It may seem radical, but have you thought about moving the stove directly below where it is by running chimney pipe all the way down to the basement ceiling?

Thanks for the quick reply ... I don't believe the duct work was insulated, but it literally runs down the entire middle of the house and is fully enclosed with drywall. Unfortunately, moving the stove to the basement would also mean moving the stairs (bigger undertaking than I'm willing at this point.)

So, I'll be experimenting with the "circ" setting on my HVAC fan tonight and over the weekend.

p.s. contractors in this part of the state do the absolute minimum for the most amount of money, and nothing you don't expressly request.

 

[FPX Dude]

Turn on that ceiling fan. Experiment with direction up or down, personally I like mine pushing air down, it feels much warmer that way.

 

[wooduser]

Yes, I think experimentation is the correct thing to do.

A forced air system should even out those temperatures all around the house,. cooling off those high temperatures, probably quite a lot, and warming up remote parts of the house ----some.

Your furnace probably has a two speed fan, the low speed usually used for heating and the high speed for air conditioning.

After experimenting for awhile, one possibility would be to modify those fan speeds.

I'm guess that the lowest speed would prove to be useful for circulating heat from the wood stove and the current speed appropriate for the heating cycle of the furnace.

 

[Rainey_inWA]

Turn on that ceiling fan. Experiment with direction up or down, personally I like mine pushing air down, it feels much warmer that way.

Yep, have two fans running on the main floor.

 

[Rainey_inWA]

Yes, I think experimentation is the correct thing to do.

A forced air system should even out those temperatures all around the house,. cooling off those high temperatures, probably quite a lot, and warming up remote parts of the house ----some.

Your furnace probably has a two speed fan, the low speed usually used for heating and the high speed for air conditioning.

After experimenting for awhile, one possibility would be to modify those fan speeds.

I'm guess that the lowest speed would prove to be useful for circulating heat from the wood stove and the current speed appropriate for the heating cycle of the furnace.

I don't see an option to control the fan speed when set to circulate. Honeywell digital thermostat.

 

[Tater1985]

I just joined the site today and am having a similar issue with heat distribution. My husband and I just designed and built our home in Eastern Washington, it's approximately 2800 sq.ft. (half main floor and half full, walk-out basement). The full basement was a bit of a last minute design change as it was initially intended to be a partial basement and more mechanical than living space. Anyway, our wood stove is centrally located on the main floor which has a great room with a vaulted ceiling and a huge ceiling fan. The stairs to the basement are also centrally located directly next to the stove. All of our duct work is captured in the floor joists (aka basement ceiling), and the basement is completely finished. We just started using the wood stove this past week (Quadra-Fire 3100) and it will absolutely toast your buns (>90 degrees) upstairs but the basement dropped to approx 60 degrees. (I'm kicking myself with the obvious design flaw now.) There is an air return in the floor right next to the stove and another in the adjacent room, plus one "centrally located" in the basement.
Since hot air rises, any suggestions on the best way to push it down the stairs and into the basement? Thanks in advance

Would it be possible and help out to have a return air duct near the ceiling on the same wall the stove is on?

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[maple1]

4 feet of uninsulated duct in the attic will lose a lot of heat. I wouldn't send any heated air through that. Even if insulated, it would need to be insulated very well.

 

[missedbass]

Uninsulated duct work in an attic is a no no in the summer also as condensation will be a problem

 

[Ludlow]

If you have an older belt driven blower, remember to add a few drops of machine oil to the oil cups on the motor once a season. Running a continuous fan makes this very important.

 

[MissMac]

I just joined the site today and am having a similar issue with heat distribution. My husband and I just designed and built our home in Eastern Washington, it's approximately 2800 sq.ft. (half main floor and half full, walk-out basement). The full basement was a bit of a last minute design change as it was initially intended to be a partial basement and more mechanical than living space. Anyway, our wood stove is centrally located on the main floor which has a great room with a vaulted ceiling and a huge ceiling fan. The stairs to the basement are also centrally located directly next to the stove. All of our duct work is captured in the floor joists (aka basement ceiling), and the basement is completely finished. We just started using the wood stove this past week (Quadra-Fire 3100) and it will absolutely toast your buns (>90 degrees) upstairs but the basement dropped to approx 60 degrees. (I'm kicking myself with the obvious design flaw now.) There is an air return in the floor right next to the stove and another in the adjacent room, plus one "centrally located" in the basement.
Since hot air rises, any suggestions on the best way to push it down the stairs and into the basement? Thanks in advance

Pushing hot air to the basement is really tough. I’m in northern Ontario, and when it’s minus 30-40 degrees C out I can only keep the basement at about 10 degrees C by running the furnace fan 24/7. Now I don’t use my basement other than to store things like my furnace, water treatment stuff and plumbing, but still I wouldn’t want it to dip any lower. I put a portable weather station down there and a secondary furnace sensor to kick on the furnace if it gets below 10. Good luck!


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[AlbergSteve]

I am relatively new to the website and have much to learn. I have several questions and will keep each of them in its own thread.

Do you guys normally operate your house's HVAC heater while you operate your woodstove? Obviously it depends if you are in Alaska or or Mississippi and what you're trying to achieve , time of year, size of your house, etc.
Here's my situation and the reason I ask:
I have always been able to heat my entire house with the wood stove alone, never turning the HVAC's heater on. The HVAC unit allows the HVAC "Fan" to run in automatic mode ( the fan only runs when the HVAC is running), or, the fan can run in "Fan" mode (meaning the fan runs continuously regardless if HVAC is running or not).
When it is super cold, it would be a little more comfortable if some of the areas distant from the woodstove for a little warmer, not a big deal, but I was wondering about running my HVAC's fan-only, to see what that does. My guess is it would make those few distant colder areas more comfortable. Also I could turn the heat on on my HVAC system, but I would like to try the fan-only mode if that will suffice; and part of the other issue is that the thermostat is probably 15-20 feet from the woodstove, those distant colder areas are upstairs. I do run 2 ceiling fans one on each level of the house. FWIW my HVAC system has 2 intake/supply registers, one on each level, the one intake register on the lower level is about 25 feet from the woodstove and in a hallway and so has a wall between the wood stove and the register, my cracked open window to allow inside air is about 7 feet from the woodstove and there are other windows cracked open for outside air.
What have you guys found about running your HVAC system at the same time as a woodstove? All comments appreciated.

Our last house was 1800' over three floors, open plan on top two floors, with an electric furnace. Wood stove on the main/middle floor. We tried running the circ fan continuously over a few days and it did nothing to heat the basement.

 

[crater22]

My nephew uses his HVAC fan to circulate the heat and he says it works good. However, he uses magnatic covers to cover over all the cold air return vents except the main one in his stove room. Anybody ever hear about doing it that way ?

 

[Ludlow]

My nephew uses his HVAC fan to circulate the heat and he says it works good. However, he uses magnatic covers to cover over all the cold air return vents except the main one in his stove room. Anybody ever hear about doing it that way ?

Need to be careful. Blocking airflow will increase the load on the motor and raise the amp draw. If the return register is fairly large it may be OK. If doing this he will really need to clean or replace the filter often. A dirty filter on top of blocked registers will burn the blower motor up fairly quickly. Then if the furnace comes on with blocked registers and dirty filters, the furnace could overheat and kick off on high limit. Keep aware.

 

[Rainey_inWA]

Pushing hot air to the basement is really tough. I’m in northern Ontario, and when it’s minus 30-40 degrees C out I can only keep the basement at about 10 degrees C by running the furnace fan 24/7. Now I don’t use my basement other than to store things like my furnace, water treatment stuff and plumbing, but still I wouldn’t want it to dip any lower. I put a portable weather station down there and a secondary furnace sensor to kick on the furnace if it gets below 10. Good luck!


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Thank God it doesn't get that cold here in n/e WA. The circulate setting on the furnace was not productive. So far, I've achieved the best result with a portable fan at the top of the stairs pointed down into the basement, in addition to the two ceiling fans. Last night the outside temp dropped to 17 degrees (F) and the basement stayed about 65.