ᐅ Compliance with Renewable Energy Act requirements using a water-heated wood stove

Hello,

Vit84 schrieb:

So my heating system, consisting of a gas condensing boiler and a water-carrying fireplace, wouldn’t be approved? Is that correct?

Apart from the fact that I wouldn’t install such a system myself—who can reliably answer your question? No one knows the rest of the wall structure, the insulation, the site’s orientation to the sun, etc.

Whether this combination is sufficient, you will only know for sure once the structural engineer/energy consultant has completed the calculations for the energy saving regulations.

Best regards, Bauexperte

@Bauexperte: Why wouldn’t you recommend this system to me?
I don’t think it’s bad, since in winter (when I mainly need heating energy) I can significantly reduce the load on my gas heater by using my water-based fireplace. The roof orientation is east-west, and construction will be either with Poroton or aerated concrete (Ytong).
Solar panels are not worthwhile, so I’d rather invest the money in the water-based fireplace.

How does the approval process actually work? I mean, a solar system that operates when the sun is shining or extracts heat from the air, so it works independently of you. A water-heated fireplace also needs to be fired up, meaning it has to be loaded with wood, etc. That is easier to estimate than the output performance required from the solar system. If the water-heated fireplace only runs once a year, it is pointless.

Okay, that is a valid point, but what if the fireplace runs every day (during transitional periods and the cold season)?

Wood-burning stoves can generally be considered, but they must have an efficiency of 85% or higher. There are only a few options available, and these almost always require an expensive storage system, which, when combined with a solar installation, does not significantly impact the overall cost.

• According to the EEWärmG (Annex 1, Requirements for the Use of Renewable Energies and Alternative Measures, II. Biomass, 3. Solid Biomass, 3 a, aa,), water-bearing wood stoves must have an efficiency of 86%.

Based on the good advice from my energy consultant, I am using a water-bearing stove from normatherm energy-saving technology, which has slightly lower legal requirements.

• Besides wood-burning stoves, the EEWärmG also addresses other systems that require only 70% efficiency (Annex 1, Requirements for the Use of Renewable Energies and Alternative Measures, II. Biomass, 3. Solid Biomass, 3 a, cc,). These include stoves and water-bearing stoves according to DIN EN 13240, which also require an efficiency of 70% or higher according to the 1.BImSchV.

Since I do not have a solar system and it does not make sense for the building’s orientation and location, I also searched for a solution (which I found with the water-bearing stove) that does not require a storage system.

Such systems have nominal outputs of up to 19 kW and actually deliver a sufficiently high share of heat to ensure that the renewable energy quota of 50% required by the EEWärmG for new buildings can be reliably met. These stoves are comparable to water-bearing wood stoves and, at around 4,000 euros, are much cheaper than automatically operated pellet stoves.
In the future, I will no longer depend on (costly) pellets but can instead heat with regular firewood.

Wood-burning stoves can generally be accounted for, but their efficiency must be 85% or higher. There are only a few options available that meet this criterion, and they almost always require an expensive storage tank, which, however, does not significantly affect the overall cost when combined with a solar system.

• According to the EEWärmG (Annex 1, Requirements for the Use of Renewable Energies and Substitution Measures, II. Biomass, 3. Solid Biomass, 3 a, aa), water-bearing wood stoves must have an efficiency of 86%.

Based on thorough information from my energy advisor, I use a water-bearing stove from normatherm energy-saving technology, which has slightly less stringent legal requirements.

• Besides wood stoves, the EEWärmG also covers other systems that require only 70% efficiency (Annex 1, Requirements for the Use of Renewable Energies and Substitution Measures, II. Biomass, 3. Solid Biomass, 3 a, cc). These include stoves and water-bearing stoves according to DIN EN 12815, which also require an efficiency of 70% or more under the 1st Federal Emission Control Ordinance (1.BImSchV).

Since I do not have a solar system, and it does not make sense given the orientation and location of the building, I looked for—and found, with the water-bearing stove—a solution that does not require a storage tank.

These systems have nominal outputs up to 19 kW and actually provide such a high proportion of heat that the renewable energy share required by EEWärmG for new buildings of 50% can definitely be achieved. These stoves are comparable to water-bearing wood stoves and, at about 4,000 euros, significantly less expensive than automatically operated pellet stoves.
I am also no longer dependent on (expensive) pellets in the future, as I can heat with regular firewood.