Natural gas + photovoltaics - Experiences with the Energy Saving Ordinance from 2016

Hello everyone,

briefly beforehand: we are not obliged to comply with Kfw 70 or KFW 55 standard, but of course with the Energy Saving Ordinance from 2016.

We want to heat with natural gas and combine this with a photovoltaic system on the roof. We will probably install a 36.5 BIMS-Therm stone.

Does anyone have experience regarding the combination of photovoltaics and natural gas? Does this achieve the required values so that you do not have to rely additionally on particularly strong insulation?

There is a lot of reading material on the internet about solar (hot water) and gas, but not about photovoltaics and gas. From my point of view, I get more energy from the sun than with two solar cells to extract the heat energy.

Thank you very much for your answers.

Good morning, KfW 70 no longer exists, so you can't comply with it.

But photovoltaics and solar thermal are two completely different things. One generates electricity, the other hot water. And as far as I know, you won't manage with a gas condensing boiler without solar thermal, but I'm not sure about that.

But the fact that you haven't really found anything about it online is already an indication that they don't really have much to do with each other.

Thank you for your response. What does gas condensing boiler mean?

With regard to compliance with the Energy Saving Ordinance from 2016, according to my research, one must ensure that either as little energy as possible is lost to the outside of the house and/or renewable energy is incorporated.

If I therefore generate energy from sunlight and include it in my energy consumption or feed surplus energy back into the grid, according to my research this is taken into account so that the general Energy Saving Ordinance is complied with. I just don’t know to what extent photovoltaics positively influence this.

Gas condensing boiler = Gas condensing boiler

For the other part, I am at a loss. Since a gas condensing boiler does not require electricity, this has, in my understanding, initially nothing to do with the primary energy demand needed for heating and hot water.

We are building a single-family house next year according to the Energy Saving Ordinance (gas, controlled residential ventilation, solar) and are currently also considering replacing the solar thermal system with photovoltaics. As I understand it, the photovoltaics must then provide the same coverage of renewable energy as the ST. That means the photovoltaic energy must go into the hot water tank via a heating cartridge. Let's say the ST delivers 2500 kWh over the year, then the photovoltaics must be designed so that it also yields 2500 kWh. Sounds simple at first.

I am currently still informing myself and have to do the calculations.

Our underfloor heating is planned so that a heat pump can also be used. If one switches to a heat pump in maybe 10 years, the appropriate photovoltaics would already be in place. Add a battery...

Our underfloor heating is designed so that it can also be operated with a heat pump. If you switch to a heat pump in maybe 10 years, the suitable photovoltaics would already be in place. Add a battery...

And why not a heat pump right away? Then you can save yourself ST and photovoltaics as of today (and the gas connection). And on the topic of battery, photovoltaics, and heat pump, there are plenty of threads here that show it can certainly be done, but it does not bring any monetary advantage.