Using Existing Hot air ductwork for circulating heat

Using Existing Hot air ductwork for circulating heat

PostBy: dlj On: Sun Sep 20, 2009 11:36 am

I've got a question for everyone. It's one that's been on my mind for awhile and I haven't found anywhere that seems to be able to answer it.

Here's the background to the questions: I have an existing oil-fired hot air furnace in my basement. I have to add in ductwork for bedrooms that were added on after the original house was built and were not connected to the hot air system. (I have no idea why not.) I burn a coal stove in my living room which keeps that end of the house nice and warm but the bedrooms are at the far end and don't get heated from the living room stove - the distance is a good 50 feet.

If I run the blower motor on the furnace, do you think this could get heat from the living room coal stove into the bedrooms once I get the new ductwork in? Do you think I may have to add in an extra cold air return duct right under my coal stove to get the hot air from the stove into the furnace plenum? My furnace is actually right under my living room coal stove.

Thanks for any and all input.

dj
dlj
 
Hand Fed Coal Stove: Vermont Castings Resolute
Baseburners & Antiques: Glenwood Baseheater #6
Coal Size/Type: Stove coal
Other Heating: Oil Furnace, electric space heaters

Re: Using Existing Hot air ductwork for circulating heat

PostBy: 009to090 On: Sun Sep 20, 2009 12:06 pm

dj, thats exactly how I set up my 'system'. I had a new Carrier Oil furnace (which I never use) with a new air handler with a variable-speed motor, installed in 2005. I have the air handler set up to run at 20% flow, 24x7x365. Just that volume is enough to mix the hot rooms and cold rooms. With the FP in the Greatroom upstairs, and the DVC-500 in the Poolroom downstairs, the air is moved and mixed quite well.
009to090
 
Stoker Coal Boiler: EFM 520 HighBoy
Hot Air Coal Stoker Stove: DVC-500 x 2
Coal Size/Type: Anthracite Rice

Re: Using Existing Hot air ductwork for circulating heat

PostBy: CapeCoaler On: Sun Sep 20, 2009 12:15 pm

Just running the existing furnace fan will mix up the air and move heat around.
Once you get the other rooms ducted it will be better.
A cold air return high on the wall in the room with your stove would be better...
Heat rises...
The problem is the furnace fan sucks a good deal of power running 24x7...
The benefit is filtered air...
Timer for the fan would help...
On for 15 off for 45...
Whatever gets the job done…
Now if you have the stove in the basement...
A better natural convection current can be formed...
CapeCoaler
 
Stoker Coal Boiler: want AA130
Hand Fed Coal Stove: DS Machine BS#4, Harman MKII, Hitzer 503,...
Coal Size/Type: Pea/Nut/Stove

Visit Hitzer Stoves

Re: Using Existing Hot air ductwork for circulating heat

PostBy: dlj On: Sun Sep 20, 2009 12:22 pm

Do you have any extra cold air returns?

My furnace is older, well significanly older, like about 30 years old. It's an old Thermo Pride. It actually runs very well and I've never had any problems with it. The blower is just an on/off option. Not like the newer furnaces as you've got with variable speed control. Maybe I could put in a variable speed motor controller and slow the motor down. Or maybe I could put in a timer and have it switch on and off at different times of the day. Or I guess I could just run it full speed all the time. I wonder if I'd have problems with the fan....

Thanks for the feed back. It's greatly appreciated.

dj

DVC500 at last wrote:dj, thats exactly how I set up my 'system'. I had a new Carrier Oil furnace (which I never use) with a new air handler with a variable-speed motor, installed in 2005. I have the air handler set up to run at 20% flow, 24x7x365. Just that volume is enough to mix the hot rooms and cold rooms. With the FP in the Greatroom upstairs, and the DVC-500 in the Poolroom downstairs, the air is moved and mixed quite well.
dlj
 
Hand Fed Coal Stove: Vermont Castings Resolute
Baseburners & Antiques: Glenwood Baseheater #6
Coal Size/Type: Stove coal
Other Heating: Oil Furnace, electric space heaters

Re: Using Existing Hot air ductwork for circulating heat

PostBy: 009to090 On: Sun Sep 20, 2009 12:25 pm

True, My setup is also for filteration and humidifying. :idea:
009to090
 
Stoker Coal Boiler: EFM 520 HighBoy
Hot Air Coal Stoker Stove: DVC-500 x 2
Coal Size/Type: Anthracite Rice

Re: Using Existing Hot air ductwork for circulating heat

PostBy: 009to090 On: Sun Sep 20, 2009 12:31 pm

dlj wrote:Do you have any extra cold air returns?

I installed one extra return, in the upstairs Great Room. I have a 16' ceiling, and I put a 8" return near the top of that, then routed it down to the air handler. That air is well over 100F when the FP is running.
No extra returns in any other part of the house. Each room has atleast 1 return, and the larger rooms have 3 or 4.
009to090
 
Stoker Coal Boiler: EFM 520 HighBoy
Hot Air Coal Stoker Stove: DVC-500 x 2
Coal Size/Type: Anthracite Rice

Re: Using Existing Hot air ductwork for circulating heat

PostBy: dlj On: Sun Sep 20, 2009 1:25 pm

I have to get ducts into those bedrooms...

I realize the cold air return would be better up high, but the installation problems putting it in become pretty tough. I'd have to do some major damage to an interior finished living room wall. The main problem doing that, is I may just remove that whole wall next year and make it open between the living room and the room behind it. Putting a cold air return on an exterior wall seems like an excercise in futility...

I've got a ranch - might be called a raised ranch, I'm not sure- but it's all one level with a full basement under it. It's long and narrow... I'm worried about the heat getting to the back. The duct work, while it will be insulated, will be running over the garage, which is unheated...

There are several problems with putting the stove in the basement
1) I want to look at it, it's beautiful
2) I'd have to run another chimney
3) I'd forget about it down there and I'd be constantly starting new fires in it...

Also, really good point on running the fan all the time... It will be a switch or a timer...

Thank you for the input.

dj

CapeCoaler wrote:Just running the existing furnace fan will mix up the air and move heat around.
Once you get the other rooms ducted it will be better.
A cold air return high on the wall in the room with your stove would be better...
Heat rises...
The problem is the furnace fan sucks a good deal of power running 24x7...
The benefit is filtered air...
Timer for the fan would help...
On for 15 off for 45...
Whatever gets the job done…
Now if you have the stove in the basement...
A better natural convection current can be formed...
dlj
 
Hand Fed Coal Stove: Vermont Castings Resolute
Baseburners & Antiques: Glenwood Baseheater #6
Coal Size/Type: Stove coal
Other Heating: Oil Furnace, electric space heaters

Visit Hitzer Stoves