Water-bearing wood stove (supplement to the air-water heat pump and controlled residential ventilation with heat recovery)?

We are building approximately 185m² with 36.5 gas concrete Kfw70 (I can add data later, but this is the point here).

In addition to the controlled residential ventilation with heat recovery (probably a Zehnder according to recommendation), a air-to-water heat pump (Buderus) will be installed as the primary heating system.
What is certain, however, is that we will also have a fireplace in the living room (atmosphere, happily making fire - primal instinct of the man, cozy quick direct warmth, etc). Side effect: When the air-to-water heat pump becomes less economical in winter, I like to put some wood (mostly homemade from our own forest) on.

!Now the idea was to use the heat of the fireplace at the same time for the whole house by installing a water-bearing stove like the "Wodtke Tio" instead of a "conventional" fireplace.
For this, the buffer tank would be increased from around 300 to 850 liters according to the heating engineer’s first (un-calculated) estimate.

Manufacturer’s info: "With a water-side output of about 70% at a nominal heat output of 8 kW, Tio heats the installation room and at the same time the buffer tank."

Would this be a good idea? (Additional cost including installation roughly estimated at about 5000 euros compared to a normal fireplace)

Including the hydraulics, the larger tank, etc.?

Yes, everything included (I also have a friend through whom I can get such things cheaper).

... I doubt whether you will achieve an economic benefit from that.

That's exactly the question..... To what extent the savings effect occurs here, I simply cannot judge. Or whether it at least brings me advantages in terms of comfort (no overheating of the room, since 70% of the heat goes into the water).

Hello Frank,

.... primal drive of man,

With all due understanding for your secret desires - you are shooting sparrows with cannons. There are now also smaller wood-burning stoves that satisfy the occasional need for "the view into the blazing fire."

You are about to spend a lot of money on a myth; the "extra electricity costs" for the operation of a pure air-to-water heat pump relate exclusively to defrosting the externally mounted fan at freezing temperatures. About 0.02% of the annual operating costs. It looks different, of course, if by air-to-water heat pump you mean a ventilation heat pump according to the provisions of the red competitor. Apart from the fact that I would never install and therefore also not recommend this, I would in your place make your heating concept dependent on the heat demand of the newly to be constructed building. There are specialists who will put together the appropriate technology for you so that in the end demand and operating costs match.

Rhenish greetings

If your efficiently running because properly planned air-to-water heat pump is installed, I would refrain from another heat generator (except perhaps a cozy fireplace stove). The originally described 300 liters – is that a buffer tank or merely the domestic hot water tank? In my opinion, it is much more difficult to efficiently connect both heat generators. For 5,000 €, you can heat for a very long time. With the air-to-water heat pump combined with underfloor heating, you could even completely avoid a buffer tank.

Best regards

Get yourself informed about monovalent and bivalent operation. There is also an air-water heat pump in monovalent operation. There is no heating element involved.

So, thanks in advance for the tips. I think I'll better skip the water-bearing fireplace (using a sledgehammer to crack a nut)... I don’t yet know which air-water heat pump to choose... it will be directly calculated and recommended by Buderus (they give me so many discounts that I can never make up the advantage in purchase price and installation by choosing another company). As soon as they give a recommendation, I’ll pass on the information. Only the controlled residential ventilation is supposed to be from zehnder, because my builder offers and recommends it directly.