Using My Forced hot air system to move air...

[sabastio]

I heat my house with Rudd gas fired furnace which is forced hot air driven. I have no AC incorporated. my question is my Jotul firelight is being installed in a week an the room where it is located is 20x20 but the catch is the ceilings are only 6’6 in this part of my 125yr old home. I want to install a “FAN ONLY” switch on my thermostate to circulate the heat. My returns are in this room. will this work or am I wasting my time? And will my blower motor burn out soon from using it in this manner? Any advice would be great

Thanks to everyone for adding so much knowledge to this fascinating industry and Life style

 

[jpl1nh]

I did the same thing you're considering though my house layout is different. I wasn't really impressed with the results and my fan motor burned out after a couple of seasons even though I was only using it intermittently. The layout difference is that I have a 1200 sq' footprint with a basement, open concept main floor with a cathedral ceiling, and a second floor that is loft with two bedrooms and a bath. The basement is not insulated and about 1/3 of it is partitioned into a finished room with heat from the forced hot air system. It seems to me that the main drawback to the idea of using your HVAC fan system is that the cold air returns and hot air vents are typically at floor level. With the furnace on you, are adding heated air to the cool air otherwise just circulating through at floor level. With the furnace off, you pretty much just continue to slowly circulate the floor level cool air and the warm air from higher up in the rooms produced by your stove does not really mix in. For me I just turned on the ceiling fan and ran that most of the time. It uses far less electricity and worked far better in distributing the stove's heat. It does not get heat down to the basement room however, and we either turn on the furnace occasionally or use an electric space heater when we are down there. If your layout is low ceilings and you are looking to distribute heat from one room to another, I would think that small circulating fans would be less expensive to operate and more efficient. You could blow cool air at floor level from other wings of the house towards your heated room and/or warm air at higher levels towards the unheated areas. PS, congrats on the new Jotul, they make a great product and I think you'll really enjoy not to mention a move towards carbon nuetral and away from increasingly un- affordable fossil fuel.

 

[CrazyAboutOrchids]

I can do this successfully in my house which is a standard New England Colonial. My family room, where our wood insert is located, is over the garage and has a semi-cathedral ceiling. We do not have an open floor plan. I use a 5" square silent doorway fan to pull air into the rest of the house which works just fine and then as the weather gets colder, I will use my furnace fan at times. We had our furnace replaced last year with an oil fired Thermopride which has a variable speed motor on it. When it is running on fan only, it costs less than a light bulb to operate. It works in my home because my supply vent in that room is up near the ceiling on the wall that runs along the rest of the house. My ducts are all well insulated. It worked with the furnace that was there before as well, but the electrical cost was higher and it was less effecient.

 

[begreen]

Sabastio, congratulations on the new stove. There are often more efficient ways to distribute the heat. Can you post a simple diagram of the floor layout?

In some houses, using the central furnace's blower will work. It requires well insulated, properly sized, ductwork. But it will use more electricity to run that motor than is often necessary. And the motor will need to be oiled, perhaps twice a year depending on the summer A/C load.

 

[Sandor]

This has been brought up on many occasions around here for years.

The only answer is for you to try it out, but don't count on it. I tried it, and it did not work.

Like BeGreen says, there are more efficient ways to move around the heat. A strategically placed fan can make all of the difference. Whether that fan is pushing cold air toward the stove, or moving warm air away from the stove is some you need to play with and figure out.

I can say that a little weather station with a remote sensor will make this much easier and accurate when your trying to figure it out.

 

[elkimmeg]

If a return system can move warm air then the entire system is designed very poorly It should be designed to draw off cold air.

No wonder people are looking for axillary heat with stoves their systems do not function correctly poorly designed and wrong return locations for heaatt.

Some how I don't get it, lets use our HVac ducts to move heat that the system fails to do sffeciently in its primary function


There are two ways to save heat or cut your consumption have a well designed primary system or use secondary heat but leaving the poorly designed inefficient system is foolish.

When the stove is not functioning and you still need the furnace then what same wastefull fuel hog runs? In no way should a correctly designed system has the ability to move warn air.

the better it works for you the more deficient your system is.


I would be real carefull removing necessary combustion make up air near a stove that the process pulls stove exhaust along with the heat and creates an expressway to spead it threw
out the home. Why do you think code requires no returns within 10' of a combustion appliance? I'ts trying to protect the innocent

 

[sabastio]

thanks for the input but my heat system works fine, I spend about a thousand a month in cold winter on gas bills.the stove will help cut costs in half. The room is 20x20 with 6'6 ceilings, The room will get very warm because of this. The returns are situated about 15 from the hearths edge. Buy using the fan only without the burner will circulate this very warm air so I don't have to open windows. The first floor is 75 feet long with 5 consecutive room all having the ceiling height gradually higher till 11 ft in kitchen. Its two floors but the upstairs is not so much of a concern. The stove is burned with doors closed, I will not be sucking any stove exhaust. The house is 3500sq ft but I'm not really trying to cook the house out, just keep it above 65 in the dead of winter

 

[Mike Wilson]

As Sandor mentioned, this topic comes up here every so often. I think the general consensus of all the prior threads is that while the system can move air, the loss of heat is too great. I have a 3 zone hydronic/air system here, and I tried to move heat in one of the zones using the air handler. The problem I encountered is that so much heat was lost during the transit of the air through the system, that the air coming out on the other end was cold. Oh, and my main intake is in the living room, where the stove is. I suppose if you have a limited system, small, with tight joints, it might work. I have had much better luck using small fans to move air inside the zone I am heating with the stove. Don't forget, a stove is essentially a space heater.

YMMV, but that's mine...

-- Mike

 

[jpl1nh]

. The stove is burned with doors closed, I will not be sucking any stove exhaust. The house is 3500sq ft but I’m not really trying to cook the house out, just keep it above 65 in the dead of winter

Sabastio, while I think Elk missed the point that the ONLY problem with your furnace was that you are paying for gas which has gotten almost prohibitively expensive, the valid points in his response are that a properly designed HVAC system is designed to pull in the cool air from a room which is at floor level, move it to the furnace where it is heated and returned at floor level where the heated air rises into the room. Without heat added into the cool air being pulled from your floor returns, it just comes back out as cool air while the warm air from you stove remains nearer the ceiling. Secondly, the point about sucking stove exhaust has to do with the wonderfully subtle processes of flue pressure in your chimney. This is a passive process primarily dependent on temperature and barometric pressure differences between the warm air in your chimney and the colder air outside. There are instances, however rare, and dependent on your particular chimney set up, how the stove is set, wind, inside outside temperature differentials, humidity, etc where even with a well sealed stove that it is possible that exhaust can be entering your home through the stove. As a building inspector, Elk is exceedingly aware of the dire consequences to you and your families' well being should this happen. Using your HVAC system can create a negative pressure within the room that could aggrevate tht situation AND then distribute harmful combustion gases throughout your house. Regardless of how low the chances are of this happening, I have never, never seen Elk stop reinforcing this point to any and all, and I have come to agree with him that even should your system happen to be succesful at distributing the warm air, its not worth the risk when fans most likely will accomplish this much better with out the potential negative pressure issue.

 

[luv2byte]

we have a 2400sq ft home with a whole house filtration system that is part of our heat pump system we had installed 3.5yrs ago. Do to the filtration system the system fan is always on. We have a Lopi Freedom insert with a blower fan attached. Between the system fan and the insert fan our house can easily get up to 78F if we are not careful. It heats all the rooms including the upstairs bedrooms with the doors closed.

 

[begreen]

That's possible in a mild climate with well-insulated ductwork, a tight house with low electric rates. I might be able to achieve similar results now that our house is tightened up and the ductwork insulated running through a conditioned space. But I won't be trying it, our house seems to equalize well without it, no point in wasting the power.

Sabastio has the exact opposite situation. Cold climate, old house, expensive electricity.

 

[luv2byte]

True we do have a 'mild' winter in comparison to areas of the country but can't say electricity is cheap here. We have friends that live in an apartment that pay $400/mo for heat in the winter. When we did live in an apartment it was $350/2mo for heat. Crazy. In our house with the heat pump upgrade, house circulation system and burning while we are home and all day on weekends our winter bill is under $80/mo in the coldest days of winter. Heat pumps use very little electricity to run a house fan, the fan on the insert doesn't use much electicity either but while burning the furnce part of our heat pump system isnt utilized nor is the variable speed fan blower for the ciculation of heat that it would put out if running. Right now we are having mild days with chilly nights that are only down to around 40F but this past winter was pretty chilly, worst in about 4yrs actually with many days and nights never going above freezing. Still had an inexpesive heat bill. Our home isn't well sealed either, its far from new (about 45yr old) and we have an all glass sunroom that is the dinning room off the kitchen which lets in plety of coldness and draft.

 

[begreen]

Yes, the newest generation of super-efficient heat pumps are great. What is your rate? Our PSE rate is about .09 per kw.

 

[luv2byte]

I'm just 2hr south of you so our winters are the same, I'm just south of Olympia. Puget Sound is crazy expensive - with everything, I am so glad we moved from ther 15yrs ago. Cowlitz co. rate is 0.0512/kw - not incuding meter cost. In Pacific Co (where our beach home is) is 0.572/kw. Much cheaper than Seattle area.

 

[begreen]

That's very cheap electric. Folks in Sabastio's region can be paying .18/kw. At Cowlitz's rate, if your friends apartment is costing $400/mo. something is very wrong (or they are heating the outdoors). Unfortunately, apartment owners don't have to pay the resident's electric bills, so often, they are not insulated at all.

Enjoy the heat pump, you made a good decision.

 

[luv2byte]

Sorry, that should have been $400/2mo but that is for only an avg 800-900sq ft apartment. Unfortunately most apartments in town use the Cadet wall heaters, they heat well but are super expensive to run and usually there are only one or two in the apt. Our old place when we first moved here from Seattle had one Cadet in the living room, nothing in the bedrooms or anywere else. Same for our neighbors house (it's small) across the street, just one Cadet - that means that the little bugger has to work overtime to keep it warm.

Either way - I know we're lucky to have the small electric bill that we do have. And all the work that goes in to chopping, stacking and burning the wood is worth it. Wood heat feels like it hugs you. So cozy.

 

[granpajohn]

I want to install a “FAN ONLY” switch on my thermostate to circulate the heat. My returns are in this room. will this work or am I wasting my time? And will my blower motor burn out soon from using it in this manner? Any advice would be great

I bet you can easily test your theories using a jumper wire before troubling with the T-stat. Also, I found (in the junk box) a 5" muffin fan yesterday which we used at the old house to help boost the furnace fan in one colder room. It is rated 7 watts. Dirt cheap, and quiet too.