Domusa DualTherm 35KW Review/Experience

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New Member
Oct 4, 2021
I had a Domusa DualTherm 35KW furnace installed in my home in November 2022. This is a Spanish made furnace/boiler that is capable of burning both wood pellets and logs. It may not be sold in North America, I don't know. It has 4 modes of operation:

1. Pellets only
2. Use Pellets to ignite Logs then burn pellets when the logs are gone
3. Use Pellets to ignite logs then stop when the logs are burnt up
4. Manual lighting of logs (i.e. match etc.)

I love the ability to burn both logs and wood pellets. As far as I can tell you get way more heat out of a load of logs than you do out of 30 kilograms of wood pellets or more. However, buying seasoned firewood is basically impossible here so I burned mostly pellets this winter so far.

I've been VERY happy with the heat output. Last winter was somewhat nightmarish with our old furnace that was in the house when we bought it and we had to wear heavy clothing/layers indoors and I was worried our youngest child at the time was sleeping in too cold of a room (in the morning his room would be 16 degrees celsius (60F) or so. So far this winter my challenge is keeping the house from getting TOO WARM (it'll easily get to 25C/77F if I let it). Our house is large (380 square meters of heated space and a heated garage on top of that, about 4000 square feet+) and this furnace has been very up to the task of keeping it warm and cozy all winter.

However, there are some problems and complaints I have about it:
1. If you do burn logs for a week or so you'll probably end up with the pellet burner clogged with debris from the burning chamber. This could be due to me not using seasoned/dry enough firewood but it seems like a design flaw. It's not that hard to fix but it's annoying.
2. It can be difficult to troubleshoot when something goes wrong. The instructions/manual aren't that great.
3. It isn't really "smart" technology and has no connection to the internet so you can't turn it on/off remotely from your phone or anything like that.
4. By default it doesn't come with any kind of remote control whatsoever like a thermostat but you can get a radio controlled one and put it somewhere in your house to allow remote control or automated control by thermostat.
5. There is no easy way to rig up a huge pellet storage container like there is with some other models. It comes with a 125 kilogram storage hopper and that's what you have to work with.

We're very happy overall due to the fact that our home is simply as warm as we want it to be. So the main problems we wanted to solve are solved by this new furnace installation. However, as an American, I am used to more automation and hands off convenience than this gives me. Having to walk down to the furnace room and turn the thing on and off is already inconvenient compared to what I called "American style" convenience and automation. People in this part of Europe have never experienced American style convenience and don't even see a point to it so it's a struggle to even get a company to understand why you want a more automated system. I am hoping I'll find a way to hook up the furnace to an internet connected control device somehow so I can monitor it and turn it on/off over the internet in the future if, for example, we're on vacation in the winter.

The only alternative furnace I considered was a SolarFocus model also capable of burning logs and pellets and it was significantly more expensive. The guys who did the installation are contractors who told us they would have also been the ones installing SolarFocus and it isn't worth the money but that all depends on how much money you have I suppose...