Integrating Pellet AND Wood heating into central HVAC Ducting

[HemiMoparGuy1981]

Hey Guys,

This is mostly copy and paste from a thread I started elsewhere on this site that I was pointed to this section. I was given a search link and also tried a little searching myself and all the info seems to be quite dated, thus not much help for my primary concern of current makes and models of stoves/furnaces that can achieve what I am looking to do.

I'm new here, found the forum by googling this question. I found and read an old thread from 2011 similar to what I was searching for. Learned a lot already. So now I am looking for the products to research. I read a lot about the Bixby UBB, it sounded perfect, I spent 30 min surfing the web to find they are no longer in business. So, I'm here asking...I am looking for pellet furnaces that are designed to be integrated, I have 2 young boys at home I don't want to add any risks to my family or myself from trying to cobble things together.

I notice a lot of the pellet stoves are aesthetically pleasing, I don't care one lick about that, I want a basic, ugly, industrial unit that will sit in the basement. A house that I am looking into buying has propane for heating, which I know is expensive. I am looking to supplement the existing furnace to lower propane consumption. My initial thoughts are to tap into the duct work being a 2 story house plus the basement...heating the downstairs would be fine with a stove on that level, all wide open. But in interest of saving floor space, and keeping the littles away from the heat source, plus it wouldn't likely do much to heat upstairs, I'm looking into the integrated setup. I was thinking that I would tap in real close to the propane furnace supply duct, and that I would run the existing furnace blower fan at all times to help crank the added heat from the pellet furnace through the house.

So, my biggest concern here is being pointed in the right direction of which stoves to look into, since my research led to ones that are no longer available; secondary concern is any advice about my expressed ideas, any advice to add, etc. Thirdly, I was curious if it is possible to integrate SOME wood burning into this mix as well. I occasionally come across firewood from side jobs of cutting trees down for customers...and I also stumbled on this video to make a pressed fire log out of junk mail and cardboard that I wanted to try. Any help is greatly appreciated.

Thank You In Advance,

Eric

 

[skalor]

You may want to look into a pellet boiler instead of a furnace. Would probably be easier to just add an water to air heat exchanger to your existing ducting. I'm running a Harman Hydroflex 60 but they don't make them anymore. You may be able to find a Hydroflex 60 or PB105 used or maybe even old stock somewhere. I'm very happy with my HF60 and a 120 buffer tank that I run in series with a propane boiler. Saves me about $120 for every ton of pellets vs what I would be using in propane at $2.30/gallon. Also a boiler would allow you to locate it elsewhere if it's more convenient because you can just run pex lines to the the ducting. I would run a small buffer though and tie the overheat loop to enable the fan to shed heat should the boiler temp get too high. There is a lot of different options but cost is probably going to be the limiting factor.

 

[Bad LP]

I gotta agree with the above. Pellet boiler, lines to water/air exchanger in the supply plenum and some control wiring.

 

[maple1]

Yes, can't recall reading much if anything about pellet furnaces.

There are or were some wood boilers that had an option to install a pellet head. Would be a bit of a PITA to change it if you were changing fuels often. Also are or were pellet heads out there made to install in place of an oil burner. Also think there is or was a boiler out there that could burn both, a multi-fuel setup. I forget the brand now, and also haven't seen much said about them. Which might not be a good sign.

 

[Wood1Dennis]

PSG makes a pellet furnace, PSG ALTERNA II . I don't know anything about it except to tell you that PSG makes a great wood furnace. I'm very happy with my Caddy wood furnace.

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www.caddyfurnaces.com

 

[Former Farmer]

What are your costs for wood pellets and LP? If you have a high efficiency furnace (90+% efficient) your gallon of LP would equal 12.5 pounds of pellets at 80% efficient. 1 ton of pellets would equal 160 gallons of LP.

One gallon of LP = 91500 Btu
One pound of pellets = 8200 Btu

91500 x .9 = 82350 Btu
8200 x .8 = 6560 BTU

What size is the propane tank? Here, if I take at least 600 gallons, I get a 5 cent discount. If you don't take at least 250 gallons, you may be getting a delivery surcharge.

I would look at the above costs first, and then factor that into the return on investment for a new/used pellet furnace.

 

[HemiMoparGuy1981]

What are your costs for wood pellets and LP? If you have a high efficiency furnace (90+% efficient) your gallon of LP would equal 12.5 pounds of pellets at 80% efficient. 1 ton of pellets would equal 160 gallons of LP.

One gallon of LP = 91500 Btu
One pound of pellets = 8200 Btu

91500 x .9 = 82350 Btu
8200 x .8 = 6560 BTU

What size is the propane tank? Here, if I take at least 600 gallons, I get a 5 cent discount. If you don't take at least 250 gallons, you may be getting a delivery surcharge.

I would look at the above costs first, and then factor that into the return on investment for a new/used pellet furnace.

I never really thought about this...I guess I just figured so many people wouldn't be doing it if it wasn't quite cost effective

 

[Highbeam]

Some parts of the country have super cheap propane and super expensive pellets. In the PNW we have cheap pellets and expensive propane so there a lot of pellet burners.

 

[3fordasho]

Some parts of the country have super cheap propane and super expensive pellets. In the PNW we have cheap pellets and expensive propane so there a lot of pellet burners.

Propane on a summer fill around here has been $1/gallon or even $.89 for the last several years. I don't know what it runs in the middle of winter because I don't use much and my tanks will still be half full by spring. Pellets at $4-4.50/bag are more expensive than propane. Pellet stove went away a long time ago.

 

[Highbeam]

Propane on a summer fill around here has been $1/gallon or even $.89 for the last several years. I don't know what it runs in the middle of winter because I don't use much and my tanks will still be half full by spring. Pellets at $4-4.50/bag are more expensive than propane. Pellet stove went away a long time ago.

I wish! LPG as low as 2$ per gallon picked up in rural areas to over 4$ per gallon plus delivery charge near the city here.

Pellets right now at peak are 250$ per ton for doug fir but you can find them under 200$ per ton in the off season. Cordwood is almost to 300$ per (short, green) cord CSD fir, alder, maple.

Parts of my state have electricity for 3 cents per kwh! That is half the cost of pellets when used for resistance electric heating.

So the point is that regional prices for fuel vary tremendously.

 

[Former Farmer]

My 2019 summer fill of LP was .69 per gallon.

I purchased 5 tons of hardwood pellets in the early summer of 2019 for 155 per ton.

Both are very good pricing and LP is cheaper per MBtu (million btu).

Probably will never be able to purchase pellets that low again.