Walltherm

[Coog]

Does anyone here own or have experience with a Walltherm unit? Looks cool but pricey. They brag on a 5 hour burn time which does not seam to be anything to brag about. Looks like a wood stove/boiler.

 

[PassionForFire&Water]

I do, but that doesn't count I guess .... .
5 hours would only represent around 30 Lbs of wood at 35,000 BTU/hr to the water
This unit needs thermal storage and you need to burn wood that is below 20% MC
If you are looking for many hours between fillings, then this is probably not for you.
If you are looking for a high efficiency hydronic wood stove with no electronics involved then you found what you were looking for.
PM me for references.

 

[maple1]

Does anyone here own or have experience with a Walltherm unit? Looks cool but pricey. They brag on a 5 hour burn time which does not seam to be anything to brag about. Looks like a wood stove/boiler.

Touting long burn times is nothing to brag about. Extended burn times comes at the expense of idling & lost efficiency. If you are judging a new purchase based just on burn times, you should be looking at an ordinary wood stove. My unit only has 3-4 hour burn times, and I'm not trading it for anything.

 

[Coog]

Touting long burn times is nothing to brag about. Extended burn times comes at the expense of idling & lost efficiency. If you are judging a new purchase based just on burn times, you should be looking at an ordinary wood stove. My unit only has 3-4 hour burn times, and I'm not trading it for anything.

Tell me more. I inquired because I am interested, not because I am skeptical. Your unit is a bit different though isn't it? What kind of money did you pay for a system like yours and how much wood do you burn a season? A regular season. Not the arctic winter we have experienced this year.

 

[maple1]

$15k, round numbers, doing 98% of it myself. $2k of that was just due to me living on the wrong side of the border for my purchase, and the distance to the dealer. It's not all that different compared to what others have on here, but it's a lot different if you've never heard of burning to storage before - which I hadn't until I found this place. Read what PassionForFire&Water said - hook it up to some water storage tanks. When the fire goes out, you're drawing heat from storage. Right now in 'normal' winter days I'm burning maybe 6 hours a day. That can go up close to 12 on the coldest of winter days here, like below -20c with some breeze. The rest of the time the storage tanks are keeping the house warm. You burn wide open until the fuel is gone - therefore no idling, no creosote, and always burning at max combustion efficiency. We're in a 20 year old 2700 sq.ft. two storey over 1500 unfinished basement on an exposed hilltop. I think I burned somewhere between 6-7 cord last year, that did all our heat & hot water for all except the 2 hottest summer months. I think I'm doing better this colder winter, on crappier wood. I've got quite a bit of windfall spruce in my pile, and white birch. That's about all I've been burning so far, around 50/50 mix. I'm really kind of curious to see how much wood I'll have left in my basement next fall when I fill it back up again. Extended burn times in units that heat water only mean increased creosote buildup, inefficient bruns, smoke, and waste of wood.

 

[AaronM]

Just curious if anyone has ended up installing one of these with some real-world feedback?

While I am quite set on an indoor boiler outside in the garage, this is the only other option I have not crossed off my list.

I see it could take the place of my existing woodstove (supplemental/back-up heat), give me hot water for a rad/storage tank, and radiant heat for the core of the house. Cranks out about the same btu as my propane water heater to the jacket.

The small firebox is not ideal, everything I've cut has been 16" .

Costs the same as an EKO 40, but I would get to skip the 150' of insulated pex

 

[AaronM]

I know there's a few other posts
https://www.hearth.com/talk/threads/walltherm-zebru-gasification-fireplace-experiences.90993/
https://www.hearth.com/talk/threads/did-you-know-this-was-available-here.85844/
https://www.hearth.com/talk/threads/indoor-wood-stove-boilers.33239/#post-33239

But still would love first hand experience from a purchaser.