Walltherm Wood Gasification Stove
Izzza
| Posted in General Questions on
What do you think about Walltherm?
Just want to know if this is even feasible or worth considering. Something like hydronic floor heating would be tricky because the subfloor is down and the house is framed so stuff like the door openings depend on the floor height which is only based on our engineered hardwood. For those who missed my previous tale, our new build peak heat load is ~ 40k Btu/h and we are doing R38 walls, R80 attic, triple glazed windows, aiming for ACH50 of 0.6-ish.
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Did you ever go over to Hearth.com? Because what you're describing sounds like the kind of wood-fired heat with heat storage that works.
What gives me pause in all of this is that in an earlier thread you said that you'd never really lived with wood heat. What you're proposing is going to be really, really expensive, and I worry that once the novelty wears off you're going to fall out of love with it. I've never gone completely depended on wood for heat, but I've had a few fires, and I've backed away, it's too much work. I grew up in New England, where a fair number of people still heat with wood, and I knew a few. From September to May they would have a far-away look in their eyes all the time, thinking about everything that needed to be done to bring in the wood. On the bright side they would often live into their eighties, thin as a rail and wiry as a fox, never going to the gym. Hauling, splitting and stacking five cords of wood a winter does that for you.
I guess what I'm saying is it's not all sitting by the hearth sipping cocoa.
Hah! But what about the hygge!
I like the idea of this if it’s just one of several heat sources - if there is an easy alternative to the wood so we could just use wood when we want to. But yes probably figuring out the whole system will end up just as expensive as the masonry heater…
It’s just so efficient 🥹
You had me at thin as a rail
You would need to add the storage tank, which could be pretty pricey for a large insulated tank. I'm not really sure what you would use. You would need a heat exchanger to heat domestic hot water from that. And then finally, a way to distribute the heat. You could use a simple system with radiators and thermostatic valves. Radiant towel racks in the bathroom are really nice. All that said, your current HVAC design doesn't really change much I think, as you still need an AC system.
You'd probably be in for more than the masonry heater on this type of system. But it probably would work well. My parents have a masonry heater. I do like it a lot. My dad will have a cord of firewood delivered already split. In the coldest parts of winter, they use it a bit more often. But I don't think they use more than a cord through the winter.
I suppose I need one final hurrah here…
I just looove radiant heat. And when I read we could have a thermostat in every room… that is what I wanted all along but it’s too complex for a ducted system. Radiant floors are nice but expensive, little modern rads are not bad. I’ve lived in a house with the fin tube baseboards, seemed fine.
I guess I’ll ask the engineer who designed our system and see if he says it’s probably not worth it.
If anything, it’s possible this might have been a good idea if we had explored months ago but maybe just due to timing this won’t work as they’re doing interior framing now and the windows have arrived.
If you’re willing to pay, it’s a fine idea! Panel radiators using low water temps is the way to maximize the storage tank. The air to air heat pump would handle cooling and supplemental heating.
Why not solar now? Solar’s the least expensive thing mentioned on this build :)
We were advised to skip solar now since it can be added later. They are putting the conduit from the attic though and we will have space for batteries in the garage. I think we planned about 14kW on the roof, we originally wanted to be off grid but it just seemed totally unrealistic. The real issue was the battery storage. Though the success of a lithium mining company contributed to being able to build the house in the first place, the batteries are too expensive. We debated starting with some batteries so we could at least charge overnight to use in daytime during peak hours for half-priced hydro, not sure if there is a term for that. I’m sure we will try to do the PV array asap but honestly there are just sooo many expenses so everything has an opportunity cost.
We’re paying so much for the hydro we figured we might as well use it… I think it’s close to $30k now to bring it up underground from the road.
In Ontario we have a government program that provides up to $40k loan for 10 years, interest free, for green home upgrades. But it is for existing homes, not new builds. So honestly we were thinking it might not be a bad idea to wait 6 months and apply for that. If they haven’t ended it yet, they’re running out of money 😂
If you're mostly wanting the experience of a wood fire while having a well sealed home I'd recommend an outdoor fire setup. While our 1980s house has an indoor fireplace I keep it sealed up and use a cast aluminum chiminea outside for times when we want to sit by a fire. Blue Rooster Company has nice ones and I don't have to worry about them being fragile like a clay chiminea.
I grew up with a wood stove as our primary means of heat and was used to the house either being cold from the fire not yet being built or hot from it roaring away. Now that we have a ducted heat pump it's magical being able to just keep a smart thermostat at a particular setting and not be dealing with maintaining a fire unless I want to. My mother in law enjoyed chopping her own wood until recently, even after a couple copperhead bites from grabbing wood in the woodpile. Now she appreciates her propane furnace more.
I understand that the walltherm boiler is fancier with finer controls than an old wood stove, but if you're just looking at it as one of multiple sources of heat for the experience of a wood fire it doesn't make much sense to me, particularly since it sounds like there are other items in your build such as solar/batteries that you're needing hold off on due to not having unlimited funds.
https://www.thebluerooster.com/product-category/chimineas/aluminum/