Adding wood heat to an existing electric furnace system

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

Aranyic

Burning Hunk
Sep 3, 2015
130
Ohio
I'm looking for some practical advice to narrow down what direction I want to go long term on wood heating. I did wood stove heating in my last house for a couple years and really liked it. Started with a Wood pro stove to an Englander NC-30 and ended up with a blazeking princess that I really loved my last winter there.

Moved to a new house that's got an electric furnace/outdoor air heat pump/exchanger. That system was installed into the house in 2008 I believe. There's also Harman P61 pellet stove that I do the bulk of the heating with. I burned about 4-4.5 tons of pellets last year heating the house.

The house is a 2 story, 2400 sqft living and about 1400 unfinished basement with poured concrete walls and floor. Decent insulation and windows (built 1993) with fairly wide doorways and hallways. All opening between rooms on the main floor are more than 38" with most over 48". Very steep roof pitch (10/12 at least I'm almost positive 12/12) so I don't really want to penetrate the roof anywhere at the end and need 10+ft of Class A sticking out of the house. It would be near impossible to clean without a lift and it would not pass the wife eye test.

RoughLayout.PNG

My initial plan was to pull out a partial wall that I have between the living and family room. Put my blazeking princess (currently in the garage I brought it with me) there and vent it through the wall. Up past the peak and then put a chase in. I'd end up with approx. 30' of chimney give or take between the class A and the stovepipe inside. There's half way decent airflow around the house with the pellet stove. A fan near the kitchen opening blowing the cool air into the stove room pretty well takes care of the main floor. Upstairs stays cooler which is fine for me sleeping; however my wife's craft room is up there and that means she will have a space heater going in there. The bathroom off our bedroom stays pretty cool also which isn't amazing getting out of the shower.

I'm considering if it's worth tying into the HVAC system in the long run; I'm 34 now and if I have my way I'll die here sometime a long way down the road. Do do that I've got two options; addon furnace or boiler install of some sort. My furnace is centered along the south side of the house and the ducting runs up the walls there. The addon furnace would probably need to go on the east wall because that's really the only place I can run a chimney all the way up near the center line of the house. Addon furnace question; can I effectively have the furnace 20' away from the main duct lines? If I go with an addon furnace I would look at something like the PSG Caddy or the Kumma Vapor.

My other option would be a boiler based with an air exchange phelum shoved into the ductwork above the furnace. It's pretty tight but I'm sure it can be done. I have 8' clearance in most of the basement with 7' a couple places that support beams span it north to south. First question probably with this direction is: how much room do you really need to put the phelum into the ductwork. And also how much efficiency is lost when doing the water to air exchange? I know it's done all the time but I'm not sure how much you lose in doing so. Boiler direction I'm open to investing everything from a Portage & Main/Heatmaster/Crown Royal gasser or a garn/EKO with storage and batch burning. I've got a 2.5 car garage that my truck doesn't fit in. Just keep my wife's car in it. Not sure if you can put a garn or EKO in an attached garage or if you get into the code issues with fumes, etc. I know they frown on stoves and you have to keep them 36" up perhaps? If they are treated the same as stoves I'd probably put the garn out but still look at a boiler with thermal storage in the basement. It could go along the east wall with the chimney in a chase up past the peak and water lines to the furnace.


I like the idea of the addon furnace as the cleanest way to get hot air into my existing system. However I'm not sure it'll work with my wanting to put the furnace so far away from the main ducts/returns. I'd also have to work with only 7' of height going under the supports.

ExistingFurnace.jpg
 
Last edited:

brenndatomu

Minister of Fire
Aug 21, 2013
6,389
NE Ohio
The boiler option would certainly be the most expensive. Look at the Heatmaster line too...hearing good things about them.
If you went with a wood furnace, being so far away is not ideal, but its been done. To me, the Kuuma VF100 would be a no brainer choice if your budget allows for it!
Callin in the reserves here @JRHAWK9 @lampmfg ….for the boiler side...hmm...how about @maple1 for starters
 
Last edited:

JRHAWK9

Minister of Fire
Jan 8, 2014
1,682
Wisconsin Dells, WI
Would you have any easy way to get wood into the basement? Walkout? If not, carrying wood up and down steps and through living space may get old in a hurry.
 
  • Like
Reactions: Hebner

Aranyic

Burning Hunk
Sep 3, 2015
130
Ohio
Would you have any easy way to get wood into the basement? Walkout? If not, carrying wood up and down steps and through living space may get old in a hurry.
Nothing as great as a walk out. I've got a 12x31 carport with a pallet floor that I will stack in just off the back of the driveway.

From there a cord or two at a time could stage in the garage without being in the way and move it through the kitchen and into the basement as needed from there. It's similar to how I managed the wood stove before but it's a bigger firebox to feed (though the englander NC-30 loved wood).

Alternate option would be taking one of the 13x30" windows in the east side of the basement and setting up a bin inside that and a chute of some sort on the outside. Fab up an insulated plug for either side; similar idea to an old coal chute or something. Drop wood through it and build a wood bin along that wall that it pile loose in.

I'm putting some feelers out to hvac companies in the area. Asking a few questions to see which ones really understand and have worked with wood heat. Start with a consult to determine exactly what I have. I believe it's a 3-3.5 ton heat pump. Existing fins/transfer unit (not sure technical name) that is hooked up to the heat pump sits in the bottom of the air handler with the blower motor on top. System installed in 2007/2008 with a 10 yr warranty. Most of the inner workings of the heatpump portion of it were replaced under warranty right before we bought the house in late 2016 judging by service stickers on the unit.
 
Last edited:

brenndatomu

Minister of Fire
Aug 21, 2013
6,389
NE Ohio
Alternate option would be taking one of the 13x30" windows in the east side of the basement and setting up a bin inside that and a chute of some sort on the outside. Fab up an insulated plug for either side; similar idea to an old coal chute or something. Drop wood through it and build a wood bin along that wall that it pile loose in.
Excellent idea! I have seen people do this and make it work well!
I'm putting some feelers out to hvac companies in the area. Asking a few questions to see which ones really understand and have worked with wood heat.
Good luck...many places wont fool with something they don't sell...even more so if its a wood furnace! And then there is the guys that will do it, but only think they know what they are doing!
What part of Ohio are you in?
 

Aranyic

Burning Hunk
Sep 3, 2015
130
Ohio
I'm about 30 miles northeast of Dayton OH; lots of older central boiler units burning in my area.
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,389
NE Ohio
Bad area for asthma suffers, 'eh?
My dad runs one of those older CB's, lives just up the road from up us...the cloud rolling across the road some days is embarrassing.
 

JMihevic

Member
Feb 3, 2018
24
Medina, Ohio
. . . I'm considering if it's worth tying into the HVAC system in the long run; I'm 34 now and if I have my way I'll die here sometime a long way down the road. . .

. . . a boiler based with an air exchange phelum shoved into the ductwork above the furnace. It's pretty tight but I'm sure it can be done. I have 8' clearance in most of the basement with 7' a couple places that support beams span it north to south. First question probably with this direction is: how much room do you really need to put the phelum into the ductwork.

I am replying since my heat pump boiler system is similar to what you are going to install. I have the "electric furnace/outdoor air heat pump/exchanger" as you do. My 2 story house is a little over 2000 Sq. Ft. built in 1980. When I built, I had the HVAC folks install a 2 row 21" X 27" X 5" hot water coil above the Heat pump Air Handler. The distance from the basement floor to the ceiling is 7 Ft. See Pic below.

My boiler is a TARM MB55 I installed in the basement. The hot water coil is more than adequate. There was no problem keeping my home at 70 degrees during a bad winter in the 70's when the temp was -20 outside. The folks on this forum would call my Tarm a "smoke dragon", but I love it. When fired right, there is very little smoke. I have no creosote problem. It is very reliable. I have not replaced one single part in the boiler in the 38 years I have had it heating my home. I have no external water storage, just the 55 gal that is in the Tarm boiler. I also have a 40 gal Amtrol Boiler Mate to heat my domestic hot water.

John M.
Medina, Ohio

P.S. I was 38 when I built my house, so you have a long way go.
P1030474A.jpg
 

mustash29

Minister of Fire
Feb 6, 2012
701
SE CT
And if you want to build a wood bin that is some distance away from that window, a poly sliding board for a youngsters play set would work great as a wood chute to bridge the gap between the window and wood bin.

My parents in PA have 2700 sqft ranch. The top of the basement only sticks out of the ground 2 feet. Half of it is a finished rec room with a huge brick fireplace in one corner that contains a Quadra Fire 5100 insert. Dad made an 8" wide "sliding board" out of plywood & 2x4's that lays on the outside concrete basement staircase. They slide the wood down the "ramp" and stack it up at the base of the stairs, then use a the "little red wagon" (that my brother and I grew up playing with) to move the wood over next to the insert. This makes the task of re-stocking wood very clean & efficient since it only requires one trip up & down the stairs to move a weeks worth of wood and requires no vacuuming on the rec room carpet.

Dad passed in Sept '17. Mom is 75 and still using this method to keep the insert going to supplement the oil.
 
  • Like
Reactions: sloeffle

warno

Minister of Fire
Jan 3, 2015
1,237
illinois
I can't say much for help with heating appliance choice but I will add in on the method of getting wood in the basement. My dad has used a 20 x 30 window that he can take out and we always just tossed the wood directly into the furnace room on the floor. Then we would go down and restack in the furnace room. He's been doing it this way since I was crapping in diapers. Only difference now is he sets the pieces on the window frame and picks them up from there to stack instead of bending over to get them off the floor.
 

E Yoder

Minister of Fire
Jan 27, 2017
577
Floyd, VA
Going buy your picture there it would be very simple to put a hot water coil in the duct (I'd consider putting it in the return at the bottom of the round duct if you can't fit in the supply) and a flat plate heat exchanger in to heat your domestic water.
An outdoor wood gasification boiler would have you up and heating with a day or two's work.
But that's the world I'm familiar with. There's more than one option obviously.
 
  • Like
Reactions: sloeffle

sloeffle

Minister of Fire
Mar 1, 2012
851
Central Ohio
I'm with @E Yoder and @JMihevic on this one. For simplicity sake I think I'd opt for a boiler with all of the storage you can afford in an outbuilding or a high efficiency OWB such as a Heatmaster GS series.

We have a wood burning furnace with a walk out basement so all of the mess stays in the basement. We carried wood into the house when we had our wood stove. I carried wood into the basement through the house when I was kid. To be frank, it sucked. If you are going the wood furnace route, I'd figure out a way to get the wood through your basement window before I purchased a unit. Most HVAC companies are hesitant to install any kind of wood furnace because of the liability. So you'll probably end up doing a self install. It is definitely by far the most economical choice but I don't think it is the best choice for your situation.
 

Aranyic

Burning Hunk
Sep 3, 2015
130
Ohio
Thanks for all the input so far. I think I may lean the boiler direction either inside or outside with storage. Water lines are going to be a whole lot easier to work with than trying to push full sized ducts 15-20 feet.

I'm leaning the direction of keeping it inside. It seems like the life expectancy of the indoor units are much longer than outdoor? I love the look of the heatmaster G line for convenience. I'm not sure that will outweigh what I envision as down sides though (and maybe I'm overstating them).

Indoor with storage: Less wood usage due to higher efficiency burning all out (pro), longer life (pro). But have to start a new fire daily and bring the wood inside (both cons).

Outdoor unit: Mess outside (pro), but more wood usage due to idle and I think shorter life? You can add storage to an outside boiler but I know I don't want to be starting new fires outside every day. If I do an OWB I would prefer to just add wood to the box every 12 hours.

I'm not 100% sure on starting a new fire very day as is. With the blazeking I started a fire maybe once a month/six weeks if I was away for more than 24 hours. Other than that I just opened the bypass; added wood at 6am/6pm. Let it char; close up the bypass and go on with life.

I love the idea of centralizing things to keep bathrooms and upstairs rooms that normally have doors closed warmer. Maybe even add a radiator type heater with a blower in the portion of the basement I have my wood working stuff in down the road. I like routine; I don't envision that I would have any issues with starting a fire once a day. In actuality it looks like the time spent running the efficient indoor boilers with storage isn't huge. 25-30 minutes of actual time to get them going and add wood once if needed?