# Using HVAC fan to circulate heat



## fran35 (Oct 22, 2011)

Greetings,
I have a basement setup of the Englander 30. It heats throughout the house pretty well, as long as the bedroom doors stay open. Being that I have two small children and need their bedroom doors to remain closed through the night, I am wondering if I could feasibly distribute the hot air in the basement through my HVAC ducts with the fan on. I have a large return vent in the basement and it really sucks air when turned on. Will this work effectively for me? Also, approximately how expensive is it to run your central heat/air fan (without the heat or A/c obviously)

Thanks


----------



## Deron (Oct 22, 2011)

Bump

Good question...we have a similar situation with a basement insert.  85 downstairs/65 upstairs.


----------



## greythorn3 (Oct 22, 2011)

i wouldnt see why not, after all as long as the furnace has a air intake inside the house it should run it thru to the vents make the air in the whole house more even you would think.


----------



## begreen (Oct 22, 2011)

This is a frequent question. The answer is maybe, but maybe not. Although 85F seems hot, this heat is often diminished via duct heat loss. In the meantime the electrical load is about 875watts/hr.. If the duct runs are long and through colder areas of the basement or crawl space the answer is probably not.


----------



## DexterDay (Oct 22, 2011)

We have tried it and didnt work all that well. There is to much temperature loss in the duct (we have new insulated ductwork) and the blower cost to much money. Up until this year we have used the corner doorway fans and just left the doors open. Does not do much in the way of Privacy when a 10 yr old boy has a bad dream or gets up to use the restroom.

I installed a Broan through the wall fan in my Sons room as an experiment. It is a 90 CFM fan, that can be hooked to a variable speed switch, so you can put it at your desired level (sound level). 

With the unit blowing in the room, there is a great deal of cold air coming from under his door. The gaps under our doors are around 1.5", to accommodate for the cold air return (when we used the furnace/yrs ago). After a few nights of running it and his room staying within 1-2* of the hallway temps. I can say that I will be installing 2 more in our house. 1 in our room and the other in my daughters room.

They were $42.00 and I might make a suggestion to just buy your own wall switch. There switch is of very low quality and is going back. I bought a standard wall mount dimmer switch for $5.00. His fan chugs along at night. 

Broan makes several units that can go through the wall. With this being at the smaller and cheaper end of there line-up. Here is a link if you wanna take a peek.


http://www.ventingdirect.com/broan-512-room-to-room-utility-ventilatory-90-cfm-3-5-sones/p417804


Some can use the Furnace and get it away with it. I have tried for several years. It will even out and regulate my temp, but making even the coldest room warmer, It did not. Would only seem to lower the Warmest rooms temps, till they equalized around the coldest temps. My home is 17 yrs old, with a New Furnace and all New insulated ducts throughout the entire house about 6-7 yrs ago. Was soon after it was installed, that we were still spending around $4,000 a yr on LP and had to do something, because a newer more efficient furnace was a giant waste of money and did not do what it was thought to do (Lower LP bill)

Lots of Ramblings, cant sleep... Had wisdom teeth pulled yesterday. The Rx seem to be working 

Here are a couple pics of my Sons fan

 Switch was not installed here. I was giving an update for another member and had to take some pics. It was quite simple. As long as you install it into a wall cavity that has an outlet in it (For your power supply), you can easily find the romex when dropping it through the drilled hole. (6" hole saw from HD did the trick, really quick)


----------



## pen (Oct 22, 2011)

BeGreen said:
			
		

> This is a frequent question. The answer is maybe, but maybe not. Although 85F seems hot, this heat is often diminished via duct heat loss. In the meantime the electrical load is about 875watts/hr.. If the duct runs are long and through colder areas of the basement or crawl space the answer is probably not.



Exactly, it may make it feel more comfortable in there but that's because you just cooled your hot room down by losing your hard earned heat through the duct work and paid electric to boot.  If you do this, I'd be sure to have thermometers in each room to make sure it really is heating them up enough to justify the cost.  If it doesn't you might as well just open a window

pen


----------



## woodgeek (Oct 22, 2011)

You just have to experiment...if the ductwork is inside the house envelope, you are fine, if it isn't (i.e. the attic or crawlspace) then put a thermo on the return (inlet) and the exhaust (outlet) to see if you are cooling in the ducts.  If your thermostat has a 'circ' feature, it will cycle on and off, maybe at lower cfm (depending on installation) and it will use less electricity.


----------



## semipro (Oct 22, 2011)

woodgeek said:
			
		

> You just have to experiment...if the ductwork is inside the house envelope, you are fine, if it isn't (i.e. the attic or crawlspace) then put a thermo on the return (inlet) and the exhaust (outlet) to see if you are cooling in the ducts.  If your thermostat has a 'circ' feature, it will cycle on and off, maybe at lower cfm (depending on installation) and it will use less electricity.


 
+1  

Also, it might depend heavily upon how high your return is in the basement.  If its low you may just be distributing the cold air from your basement floor throughout the house only to have it replaced by cold air coming down the steps(?) from the 1st floor.  The air is our basement is highly stratified by temp when our stove is cranking.

We have a very quiet bathroom fan mounted in the ceiling of the basement that pushes hot air into our existing HVAC ductwork.  Its tripped by an inexpensive thermostatic switch.  Our ductwork is completely within our conditioned envelope so duct heat losses are a non issue.  Disclaimer: this has to be done properly with fire codes in mind.


----------



## egclassic (Oct 22, 2011)

I am going to try running my furnace fan for a little while each day. It got so dry in the house last winter. I did a little reconfiguring the controls on my furnace, I have the humidifier wired to run whenever the "fan" runs, with or without a call for heat. I just have to remember to turn the humidistat off in the spring.


----------



## ScotO (Oct 22, 2011)

[quote author="DexterDay" date="1319285219"] I installed a Broan through the wall fan in my Sons room as an experiment. It is a 90 CFM fan, that can be hooked to a variable speed switch, so you can put it at your desired level (sound level). 

With the unit blowing in the room, there is a great deal of cold air coming from under his door. The gaps under our doors are around 1.5", to accommodate for the cold air return (when we used the furnace/yrs ago). After a few nights of running it and his room staying within 1-2* of the hallway temps. I can say that I will be installing 2 more in our house. 1 in our room and the other in my daughters room.

They were $42.00 and I might make a suggestion to just buy your own wall switch. There switch is of very low quality and is going back. I bought a standard wall mount dimmer switch for $5.00. His fan chugs along at night. 

Broan makes several units that can go through the wall. With this being at the smaller and cheaper end of there line-up. Here is a link if you wanna take a peek.





> Dexter, I really like this idea, esp. for my large dining room area.....it is the room that seems to lack the heat a bit, and is adjacent to our large living room where I have the NZ3000 going in, there will be plenty of heat there to steal for the dining room....I may steal yer idea and do this in that room....do you know if Broan makes these TTW fans in any other colors?.....I would like bronze or black, but I guess I could probably paint the plastic housing a with a bronze paint and it would be fine....thanks for the tip.....


----------



## DexterDay (Oct 22, 2011)

Scotty Overkill said:
			
		

> DexterDay said:
> 
> 
> 
> ...


----------



## begreen (Oct 22, 2011)

In general you will often get better results blowing the cooler air, low, towards the warm. You might try this simple experiment. Take a 12" table fan and place it at the top of the basement stairs, pointed downward, blowing down the stairs. Run it on low or medium speed. For many people that is enough of a boost to natural convection to drop the basement temp about 5 degrees and raise the upstairs temp the same amount. The same principal works well on the same floor. We've had many reports of success in harder to heat ranch homes with the stove on one end of the house and bedrooms on the other end.


----------



## ScotO (Oct 22, 2011)

DexterDay said:
			
		

> Scotty Overkill said:
> 
> 
> 
> ...



I know what you mean about work.....I've been TRYING to get my NZ3000 installed in our living room (which is completely torn down to the studs, but thats another story) so we dow what we can WHEN we can...lol....had my wisdoms out in April and at the tender age of 38 that was not fun....but glad they are gone, never even know they were ever there..and you are right about this site, lots of good info, field tests by other members, the occasional critic (which is a good thing) esp. with the context of what we are talking about on here.....this is the best site I have ever joined, I am actually doing something constructive again with my computer.....lol...


----------



## Jackfre (Oct 23, 2011)

I would suggest that you check out www.tjernlund.com and look at the Airshare product. Excellent room to room and floor to floor transfer.


----------



## ScotO (Oct 23, 2011)

Jackfre said:
			
		

> I would suggest that you check out www.tjernlund.com and look at the Airshare product. Excellent room to room and floor to floor transfer.



Great link, Jackfre......thanks for sharing it, I will check this out......


----------



## TK-421 (Oct 23, 2011)

It really depends on your situation.  We had issues last winter with our upstairs being too hot.  We opened the bedroom windows in the winter.  We had one large return that was upstairs so it pulled all the air downstairs up.  Our downstairs was very cold.

We hope this year with our renovation that the system of pulling the air will in fact pull the air from the front room towards the unheated back of the house.  All our runs are in e center of the house.  We have no basement or attic.  Our runs to the registers are all short as well.

We still don't expect much warm air out of the registers but we do expect the return ducts to pull the air from the warm great room.

I'll let you know how are setup works in a few months.


----------



## krex1010 (Oct 23, 2011)

This works reasonably well for me, it really depends on where your air returns are located. And it doesn't really move the heat so much as it just helps balance the house out with the air circulation.  It probably won't do a good job of heating rooms with closed doors


----------



## webbie (Oct 23, 2011)

There are a few potential issues here.

Running air through a large system will certainly cool it of - maybe more than the heat gained. In other words, this fan was made to circulate 100,000+ BTU, and trying to circulate 10-15K could be fruitless.

There there are the fire and smoke issues. As I understand it, basements in many modern homes are not considered part of the living space and there is an assumed division between the two. Opening a duct downstairs effectively mates the two floors together. 

Negative pressure and smoke can be an issue! Pulling air from the basement via a return causes a slight vacuum in that room - and this can suck smoke right down the chimney and make a stove reverse! As you can guess, this smoke or CO (in the case of an oil furnace, coal, etc.) would then be sucked into the ducts and deposited into the living area upstairs.


----------



## Swedishchef (Oct 23, 2011)

FWIW, my uncle setup a pellet stove in a room beside the oil furnace at my grandmother's place. The pellet stove heats this room to about 28C. He connected his cold air intake duct from the furnace to that room. He simply turns the blower ON and it circulates the heat. He hooked the blower switch to a thermostat and he no longer tends to the blower, only the pellet stove.

They went from using 9 (yes, 9) full tanks of oil per year to 2. 2/3 oil less. He saves about $3000 a year in heating. It's an older house with a TON of room (3500 sq feet or so).

For them, using HVAC worked. For others it may not. Like some people said, it may work depending on your setup.

Andrew


----------



## lawnarjax (Oct 23, 2011)

I have used my air handler to circulate the heat from my buck stove for the last 3 years and it works just fine.  I have a 3100sf split level home where the stove is located on the main level.  About 3 feet from the stove is on of the two large return registers. The stove is in a 20x15 great room with high ceilings and a huge fan.  I crank the wood stove up and without the airhandler running I can take the room from 60-65 degrees to 80+ in under an hour.  Turn on the handler and the room drops down and I get 75 degree air on both the upper and lower levels, I check at the vents with a laser thermometer.  The other parts of the house never get as warm as the room with the stove, but that is fine by me.  I can keep the rest of the house at 65 when its in the 30s out.  Best of all I have yet to pay for wood and heat for free all winter thanks to the storms we have in the summers here, keeps craigslist full of free wood ads.   Summer is a different story as my ac costs 300+ a month.


----------



## Village Idiot (Oct 24, 2011)

I have been running my HVAC fans to distribute the heat on my upstairs zone. I found some programmable thermostats (LUX CAG1500) that have a fan circulation feature that I have noticed helps keep the smaller rooms and closets from getting stale. They run from 9 - 60 minutes every hour. I have them set at 9 minutes and this is helping filter the air as well.

I am going to keep an eye on the electric bill to see what it is costing me to run the fans.


----------



## TK-421 (Oct 26, 2011)

I ran a test this morning.  Downstairs temps were 79 and 75 in different parts of the house.  The great room with the stove was around 85.  Stove temp in my 75 VC was 6-700.  Upstairs bedroom temps were 66. 

I ran the hvac fan for 15 minutes.  The thermostat is close to the downstairs return and it dropped two degrees.  The upstairs bedroom went to 71 degrees.

Looks like in my case running the fan moves and distributes the air a bit.

I had an indoor outdoor thermometer with the outdoor probe stuffed about a foot down the bedroom duct.  It ran within a degree of the indoor bedroom temp.

I'm gonna punch a hole in the wall of my great room peak at the 11-12 ft height, add a register and pipe it into my supply plenum. 

The cathedral celing temps are running around 90-ish.  That will heat our upstairs nicely.


----------



## jrprusak (Oct 26, 2011)

I run my furnace to move heat from the basement stove up to the next 2 floor levels and it is great, helps clean the air via the furnace filters which is better for my wifeâ€™s asthma....

Yes it adds to the electric bill if ran around the clock, so I installed a timer to run the fan on cycles or I can operate the furnace fan from the thermostat located on the top level...

Have a HVAC guy look at your system to make recommendations and maybe have them do some static air pressure testing to balance the air flows....






			
				fran35 said:
			
		

> Greetings,
> I have a basement setup of the Englander 30. It heats throughout the house pretty well, as long as the bedroom doors stay open. Being that I have two small children and need their bedroom doors to remain closed through the night, I am wondering if I could feasibly distribute the hot air in the basement through my HVAC ducts with the fan on. I have a large return vent in the basement and it really sucks air when turned on. Will this work effectively for me? Also, approximately how expensive is it to run your central heat/air fan (without the heat or A/c obviously)
> 
> Thanks


----------



## Blue2ndaries (Oct 26, 2011)

I just did this last night as I was curious about temps and air circulating myself.  I turned on my HVAC fan and I took my Fluke 62 IR thermometer and shot the return located in the vaulted ceiling ~17 feet above my stove (see pic).  It read 98deg which was about 2hrs after lighting the stove.  I have seen temps over 105deg up there when the stove has been going for a while.   I walked over to another room and shot the vent on the floor and got 86deg.  After 15-20min I went back to the ceiling cold air retun above the stove and shot it again and it had dropped to 94deg.  So I think it is at the minimum doing a good job of circulating the trapped warm air in the ceiling, if not actually providing warm air thruout the house.  Our house is 2934sqft, pretty open floor plan, new construction, 2.5yrs old w/good insulation and insulated ductwork, no basement, single level except for an ~1000sqft unfinished bonus room area over the garage.


----------



## begreen (Oct 26, 2011)

That sounds about right - a 20 deg duct loss with insulated ducts. So imagine what the air temps coming out of the registers would be if the return was in the floor and going through a cool basement. 30 deg duct loss is not uncommon with an older system. Even if it is 80 in the room, the air coming out of the ducts could be 50-60F. Yes it will cool down the hot room, but often it does not warm up the rest of the house. A simple fan, on the floor, blowing air from the cooler part of the house toward the stove area is much more efficient (no duct loss) and uses less electricity.


----------

