No existing distribution system: Wood Furnace or Boiler?

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scelder

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Jun 19, 2014
46
Indiana
I'm interested in everyone's input on this situation:

I have a 3000 sq. ft. historic brick home, with large open two-story central hallway that divides the home in two. I'm currently living on one side, heating with a Harman Accentra pellet stove and supplemental electric. I'm considering moving the kitchen, which would free up a room with a chimney to use as a utility type space (laundry / pantry / chest freezer area). This also opens up the opportunity to install a wood furnace.

I've previously investigated the possibility of an outdoor wood boiler as well. There is no HVAC distribution system in my home to hook on too with either system. With a wood boiler, I would look at running a few heat exchange plenums with fans directly into spaces, but with no further ductwork - I think this would easily heat the entire house (one or two plenums on either side, with PEX easy to run to distribute hot water from outdoor boiler).

The furnace would be bulkier to duct, but would still provide the necessary BTUs.

From my perspective, the furnace advantages are:
1. Cost - the units are far less expensive (even going with a Kuuma) and the installation is straightforward (for the unit itself, if not the ductwork).
2. Ease of installation -- I'm not a plumber, I don't have a backhoe, but directing airflow and return through ducts and hooking up a wood stove to the chimney seem fairly straightforward (Correct me if I'm wrong!) as compared to a boiler.
3. Longevity -- no pipes to burst, more basic operation, etc, etc, as compared to boiler.

The Boiler advantages would be:
1. Better heat distribution (easier to run pex than ductwork without disturbing the home too much).
2. Keep the mess outside
3. Keep the fire outside (perhaps safer than furnace in a worst-case scenario).

So - if you had a big shell to heat, a historic home that you didn't want to hack up TOO much, no existing distribution network, and more time than money -- what would be your move?
 
I would likely put a boiler in the basement.

This would usually come down to situational specific stuff. And some preference. In a retrofit it is usually easier to run pex lines (oxygen barrier) up through floors & ceilings to the whole house & put some rads in than trying to do ductwork or air handlers.

If I wanted a boiler but wanted it out of the house, I would put an indoor boiler in an outbuilding. But then you're into undergound piping. Dont think I'd do a typical OWB.
 
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You didn't mention if you had access to natural gas. If you do a mod con gas boiler with an external vent is hard to beat. If you do a home run system, pex can be fished through wall to radiant emitter on the walls. I don't hink air handler would work well with and old house as generally the exterior walls are quite draft and cold so you need a heat source on the exterior walls.

Don't think about an OWB unless you are in the middle of large lot with no neighbors and you don't mind exposing yourself and those who live in the house to unhealthy air emission much of the year. There is reason why OWBs are effectively banned in many states. You also will be burning twice as much wood.

Once you have put in base natural gas system and low temperature emiiters (fancy baseboards set up for low temperature water), then you can consider making the jump to an indoor wood boiler and 500 of so gallons of storage.

Please note spend the money first to get an energy audit and upgrade the overall envelope. If the house is sieve no matter what you use for heat you will be using a lot of it.

The biggest bang for the buck these days by the way are cold source minisplits. They both heat and cool and as long as the temps don't drop below zero they throw out a lot of heat, Just a new circuit and 3" hole in the wall and they are running in a day.
 
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Ours is much like yours but larger, For us AC is required so put the boiler HX in furnace plenum. Only hot water enters our historic home. Our boiler only heats the downstairs so the upstairs is a comfortable 4-5 degrees cooler. We're of the out building clan. Take your time and study here.
 
scelder said:
I'm interested in everyone's input on this situation:

I have a 3000 sq. ft. historic brick home, with large open two-story central hallway that divides the home in two. I'm currently living on one side, heating with a Harman Accentra pellet stove and supplemental electric. I'm considering moving the kitchen, which would free up a room with a chimney to use as a utility type space (laundry / pantry / chest freezer area). This also opens up the opportunity to install a wood furnace.

I've previously investigated the possibility of an outdoor wood boiler as well. There is no HVAC distribution system in my home to hook on too with either system. With a wood boiler, I would look at running a few heat exchange plenums with fans directly into spaces, but with no further ductwork - I think this would easily heat the entire house (one or two plenums on either side, with PEX easy to run to distribute hot water from outdoor boiler).

The furnace would be bulkier to duct, but would still provide the necessary BTUs.

From my perspective, the furnace advantages are:
1. Cost - the units are far less expensive (even going with a Kuuma) and the installation is straightforward (for the unit itself, if not the ductwork).
2. Ease of installation -- I'm not a plumber, I don't have a backhoe, but directing airflow and return through ducts and hooking up a wood stove to the chimney seem fairly straightforward (Correct me if I'm wrong!) as compared to a boiler.
3. Longevity -- no pipes to burst, more basic operation, etc, etc, as compared to boiler.

The Boiler advantages would be:
1. Better heat distribution (easier to run pex than ductwork without disturbing the home too much).
2. Keep the mess outside
3. Keep the fire outside (perhaps safer than furnace in a worst-case scenario).

So - if you had a big shell to heat, a historic home that you didn't want to hack up TOO much, no existing distribution network, and more time than money -- what would be your move?
Click to expand...



=======================================================================================================

NO PEX, NO MESS, NO DIGGING, no pumps, no issues with playing with Delta T Delta P or Lamda and
on and on with the simplicity of Gravity Hot Water Heat with a smaller boiler in the basement provided
you insulated well.

Sure you would have to bleed the radiators at the start of the heating season and add back water
but its so simple to use and own.

You could then use a much smaller boiler and a non pressurized water tank for
thermal mass to feed the return water to the boiler sump and one inch pipe to
all the hot water radiators in a common vertical chase for the hot water pipe to feed
the hot water radiators and use just one wall or two walls of the home for the radiators.
 
You don't want to try to put a wood boiler in the basement unless you have outside access without stairs....at least I wouldn't. !!!

Also pretty sure you couldn't buy an OWB even if you wanted to, unless it was an outdoor gasifier, the smoke dragons aren't being made anymore.
 
I used to have my boiler in the garage, I've moved it into what was the kitchen. To me it seems significant (reduction in logs used) compared to before, but of course no two winters are identical. I now have the benefit from the "waste" heat from the boiler and the storage tanks heat leakage being, now, within the envelope of the building. Also I don't have transmission heat loss in the pipe from garage-to-house.

But the first thing I would do is insulate. Every $ spent on insulation is saved every year thereafter, and it increases the comfort level too (no / reduced draughts means a thermostat setting a couple of degrees lower is still comfortable, and of course reduced air leakage means not heating the air which then just escapes outside!)
 
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You don't want to try to put a wood boiler in the basement unless you have outside access without stairs....at least I wouldn't. !!!

Well, maybe - but he did say he was considering a furnace down there. Not much difference between them in that respect.



 
Boiler with storage. Pex. Panel radiators.
 
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gassifing boiler with storage if budget allows. furnace would be second choice if couldn't afford boiler
 
You should check with your homeowners company before you plan too much, some will drop you for wood fire in the house, some will gouge you a lot of $$$$$. Many old homes are timberframed, requiring cutting or drilling through 6x6's, 8x8's etc. A lot to consider here.
 
boiler, pex, panel radiators, or refurbish old cast iron ones if you can. If you need heat now, do a gas boiler, and then upgrade to the wood boiler when you can/can afford it.

We re-do heating in houses regularly with no infrastructure (old farmhouses with a wood stove in the basement, or 70's ranches with electric baseboard only. the only sensible thing to do if you don't need AC is panel radiators. I just did one with a Heatmaster G-100, baseboards in the bedrooms, and big panel radiators in the living room/common area. the boiler modulates, and all the panel rads have thermostatic radiator heads, so the whole system just modulates up and down. the customers LOVE it.
The places we can snake a couple pieces of 1/2" pex boggles the customer's mind, and they have nothing to look at but the radiators.

honestly I really like the idea of mini splits for shoulder season/AC, and panel rads for when it's cold enough to keep the boiler from idling.
If I was starting from scratch, that's what I'd do. actually, that is what I am doing in a farmhouse I'm renovating.
 
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Karl_northwind said:
boiler, pex, panel radiators, or refurbish old cast iron ones if you can. If you need heat now, do a gas boiler, and then upgrade to the wood boiler when you can/can afford it.

We re-do heating in houses regularly with no infrastructure (old farmhouses with a wood stove in the basement, or 70's ranches with electric baseboard only. the only sensible thing to do if you don't need AC is panel radiators. I just did one with a Heatmaster G-100, baseboards in the bedrooms, and big panel radiators in the living room/common area. the boiler modulates, and all the panel rads have thermostatic radiator heads, so the whole system just modulates up and down. the customers LOVE it.
The places we can snake a couple pieces of 1/2" pex boggles the customer's mind, and they have nothing to look at but the radiators.

honestly I really like the idea of mini splits for shoulder season/AC, and panel rads for when it's cold enough to keep the boiler from idling.
If I was starting from scratch, that's what I'd do. actually, that is what I am doing in a farmhouse I'm renovating.
Click to expand...
I just picked up some cast iron radiators that I will be using in man town (girls allowed) and I plan on removing my baseboards from the bedrooms and office area. When I finally get the indoor boiler I want to take full advantage of my RFH and lower water temps.
 
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