ᐅ Is a wood-burning stove with water heating practical?

We are planning a new build and would like to have a wood-burning stove because we have quite large supplies of firewood. The "standard" underfloor heating will be powered by a heat pump (air-source or geothermal). The electricity for this will be generated by our own photovoltaic system. In new, well-insulated houses, a traditional wood stove mainly serves an aesthetic purpose, as energy savings are practically negligible. Now, the idea of a water-heating stove came up. Especially in winter, on cloudy days when the photovoltaic system doesn’t produce enough energy, this stove could be used to heat both water and the heating system. Does anyone have experience with this kind of system, or is it nonsense?

My parents installed this to bridge the period when the air-to-water heat pump would otherwise be relatively expensive due to outside temperatures. However, they retrofitted it in their existing house, so they don’t have underfloor heating but regular radiators, and no photovoltaic system either. I’m not sure how practical it is to combine this with underfloor heating and photovoltaics in a new build.

Short and simple: no

Heidi1965 schrieb:

In new well-insulated houses, a standard wood stove mainly serves for aesthetics, as energy savings are almost impossible.

You’ve already answered your own question. This also applies to the water jacket. Additional investment and operating costs far exceed any potential savings.

Heidi1965 schrieb:

In new, well-insulated houses, a standard wood stove mainly serves as an aesthetic feature, since energy savings are hardly achievable.

What do you mean by that?

At first, I also thought a water-heated stove would be great. But the cost-effort-maintenance ratio ended up canceling all the benefits.

Heidi1965 schrieb:

We are planning a new build and would like to install a wood stove since we have quite large wood supplies. The standard underfloor heating will be powered by a heat pump (air-source or geothermal). The electricity for this will be generated by our own photovoltaic system. In new, well-insulated houses, a conventional wood stove mainly serves an aesthetic purpose, as energy savings are hardly achievable. Now the idea of a hydronic stove came up. Especially in winter on gloomy days when the photovoltaic system does not produce enough, this stove could keep both water and the heating system warm. Does anyone have experience with this system or is it nonsense?

Nonsense.

You have completely different system temperatures. The stove delivers about 100°C (212°F) to your storage tank, the heat pump operates at around 30°C (86°F). The underfloor heating is designed for a maximum of 30°C (86°F). This will not work at all.

However, we have a 300m² (3,230 sq ft) KfW 40+ house and at 0°C (32°F) we comfortably heat the entire house using just convection, controlled residential ventilation, and one stove (Justus Reno R) in the living room / open-plan area / 70m² (750 sq ft) on the ground floor.

The living room temperature ends up around 26-27°C (79-81°F), but the bathroom upstairs still has 22°C (72°F), and all rooms reach 21°C (70°F) even with doors closed. With the living room at 23-25°C (73-77°F), all rooms get just under 20°C (68°F) with doors open, and 18-19°C (64-66°F) with doors closed. Crisis-proof heating in a well-insulated new build can only be achieved with a conventional stove—and comfortably warm, not barely warm.

And if anyone complains that 27°C (81°F) is too warm: first, just take off some clothes. Second, if you seriously want warm water to arrive in the tank with the hydronic stove, you will have to overheat the installation area.

Heidi1965 schrieb:

In new, well-insulated houses, a standard wood stove mainly serves an aesthetic purpose, as energy savings are hardly achievable.

That is true in most cases. However, a masonry heater can take on the main heating role. We use one as our primary heat source and have neither a heat pump, gas, nor oil systems, no underfloor heating, and no ventilation system. This way, the stove fulfills its traditional function.

Heidi1965 schrieb:

Especially during winter on gloomy days when the photovoltaic system does not generate enough electricity, this stove could potentially keep both water and the heating system warm. Has anyone had experience with this setup, or is that nonsense?

We decided against combining it with water heating, as the water jackets require frequent, thorough cleaning of the flue channels to maintain efficiency, which is an unpleasant and messy task.

“Nonsense” is a very subjective term. What matters is what brings you joy and does not harm others.

From a purely economic perspective, there are usually better alternatives than the stove.