Complement gas heating with wood gasifiers, water-bearing fireplaces, and solar energy

I brought the wood into the house but it stayed cold.

Pellet heating? Woody one that can also produce hot water… everything is possible

When will all these investments ever pay off?!?!

Domestic water and heating water are always separate. The buffer tank must be significantly larger, at least 1500 liters or, if you have space, even double that. Solar provides enough for the domestic water in summer; 4-6 m² are sufficient, and nothing in winter. 25 kW + 2x5 kW also seems very much to me. I would take 2 normal wood stoves, they are significantly cheaper. If you can program a controller yourself, you can try to combine it with the gas heating. If not, I would take the best controller in the world, your right hand, and operate it manually.

Domestic water and heating water are always separate. The buffer tank must be significantly larger, at least 1500l or if you have space, even double that. Solar provides enough for domestic water in summer, 4-6m² is enough, and nothing in winter. 25kW + 2x5kW also seems very much to me. I would take 2 completely normal wood stoves, they are much cheaper. If you can program a control system yourself, you can try to combine it with the gas heating. If not, I would take the best control system in the world, your right hand, and control it manually

You can't say that like this. Our solar thermal system has delivered over 60 degrees even at deep sub-zero temperatures (we use it for water and heating support). Of course, in the darkest winter months it is only a little, but not nothing. Friends of ours have had solar thermal for 6 years and with 5 people they don't need gas at all between May and September/October and significantly less in the transitional seasons than before solar thermal.

For a 25 kW HVG, a minimum of 2000l buffer and separate domestic hot water (fed from the buffer) is required. If you want to only turn on the HVG once a day, choose a different one. Attack SLX Lambda (for example) has a filling chamber twice as large and the control system is great. With Atmos, it depends on the boiler; is there one now with automatic control?

I wouldn't combine it with gas, but with a heat pump instead. The heat pump then goes directly into the supply line, not through the buffer. Heat pump with a lower heating curve than the control for the HVG. Then the heat pump automatically switches off as soon as the storage delivers more temperature and back on when it cools down.

You can't say it like that. Our solar thermal system has produced over 60 degrees even at deep subzero temperatures (we use it for water and heating support). Of course, in the darkest winter months it's only a little, but not nothing. Friends of ours have had solar thermal for 6 years and with 5 people between May and September/October they don't need any gas at all, and in the transitional periods significantly less than before solar thermal.

Are you actually aware of what it costs to make hot water with gas? I need 20m³ per month, a large family maybe three times that.... I can make hot water with gas for many years before a solar thermal system pays for itself^^

1500L buffer tank?!?! for what?