Heating: half-knowledge, differing advice, uncertainty

Hello everyone,

we will start building our single-family house (220 sqm living space + basement) at the beginning of 2018.

Basically, we do not place any value on any KfW standards.
Initially, a gas boiler (gas connection already included in the land price) with solar thermal energy and a tiled stove with a water jacket in the living room was planned.

Now, we had an appointment with an installer a week ago. He told us that in this constellation we cannot comply with any building regulation (Energy Saving Ordinance? 30% renewable energies?).
He said that we would either have to go for a heat pump or pellet heating, or we would need a central ventilation system in addition to the above configuration.

We then informed ourselves accordingly and were leaning towards "heat pump + photovoltaics."

Today, another installer came. He said: Gas + solar thermal is no problem at all if properly designed. He recommends it to every builder with an existing gas connection.

So what is true now? What is really recommended?

hm difficult, there is actually no real recommendation. The annoying thing is that this topic is also a matter of personal wishes and preferences. In the end, it depends on what is important to you. If you want to be as (not completely) independent as possible from rising energy prices, then only a heat pump (e.g. geothermal) with photovoltaic and possibly storage is an option. But if it should be cheaper overall in construction and energy prices are secondary, then I would go for gas and solar thermal.

Since we do not have gas available, the decision was easy, we are building a heat pump with photovoltaic and storage. And regarding the recommendations of the installers, everyone will only recommend what they are familiar with, and heat pumps in combination with photovoltaic are still uncharted territory for many because a proper design and further adaptation of the systems is more complex than gas + solar thermal.

The decision is indeed not easy because there are advantages and disadvantages to all options.

Is it correct that with Gas+Solarthermie I currently cannot comply with valid building regulations (Energieeinsparverordnung??)?

... Is it correct that with gas + solar thermal currently valid building regulations (Energy Saving Ordinance??) cannot be complied with?

This cannot be answered like that, as it is calculated. Often, better insulation is sufficient, then you have to look at the ratio of walls to windows. But if he actually means the 30% renewable energy for the Energy Saving Ordinance 2016, then solar alone is probably not enough. An additional controlled residential ventilation system should be sufficient, but in my opinion, you should have it anyway. Considering the size of your house, you probably cannot ensure manual ventilation and should plan for it!

P. S. Your fireplace probably won't be enough?!?

we also have gas, solar thermal energy and also had to install a residential ventilation system (but we wanted to anyway).

Best regards
Sabine

According to our energy calculation, it was tight but possible to operate only with gas and solar for the domestic hot water. Integrating solar into the heating system would have been a possible next step; alternatively, integrating a fireplace into the heating system or controlled residential ventilation...

So there are several options, and an energy calculation specifically for your house should be made.