ᐅ Masonry using Ytong blocks, 24 cm or 30 cm thick, for a single-family house?

xMisterDx schrieb:

Yep. If you add the extra cost of 15,000 EUR plus ...

- So, my ground source heat pump cost 10,000 EUR (without waiting time), and the drilling was another 7,500 EUR. If you subtract the gas connection fee from that, with your gas boiler, you should have even received money back from the heating technician and be in profit, right? ;-)

So, I have an air-to-air heat pump and gas heating with solar panels.
The air-to-air heat pump has a SCOP of 4.6 according to the datasheet.
I have used 840 kWh so far this winter. That equals 3,850 kWh of heating output.

I usually use around 8,000 kWh of gas, so this fits well; the winter isn’t over yet.

Gas was worth it back then; I had years where the monthly payment was only 28€.
How could you justify an expensive ground-source heat pump drill in that case?

In the end, I would have saved money if I had just installed a multi-split air conditioning system during construction in 2013. The whole fuss with underfloor heating or complex systems is wasted money for our insulated small houses. That’s why I just kept the gas heating. Cooling through underfloor heating is risky and complicated.

Nutshell schrieb:

How can you justify an expensive ground drilling in this case?

Hardly justifiable for a single-family house anymore. However, for multi-family buildings with 4-8 units, it often becomes cost-effective. Another advantage is that the system is installed entirely indoors, so no outdoor unit is required.

parcus schrieb:

Even the CO² balance almost equals that of gas or worsens with a decreasing seasonal performance factor. (Primary energy factor gas 1.1 vs. electricity mix 1.8, even if policy sets heat pumps at 0.0)

What kind of figures are those, and what sources are you using? I can’t follow them at all and I claim: THE NUMBERS ARE WRONG!

BAFA calculates natural gas emissions at 201g CO2 per kWh (eew_infoblatt_co2_faktoren_2021-1.pdf), and according to the German Environment Agency, the German electricity mix had an emissions factor of 420g CO2 per kWh in 2021.

With natural gas, you can roughly assume a 1:1 conversion for heating. A heat pump in an existing building with a seasonal performance factor (SPF) of 3 therefore results in about 140g CO2e per kWh. In new buildings, the heat pump must reach an SPF above 4 (otherwise it’s poor quality) and thus achieves about 105g CO2e per kWh.

This means that the heat pump in new buildings is only half as climate-damaging as gas. Our climate targets according to the Paris Agreement 2015 require neutrality by 2050 – so heat pumps will only improve as the electricity mix gets cleaner. Gas remains gas, and heaven forbid if someone now brings up hydrogen.

@OWLer
The primary energy factors are the current ones and must be used as the basis for every thermal insulation and heating load calculation.
Regarding the values from BAFA, a distinction must be made between lower heating value and higher heating value, which is correct. However, energy consultations may also change usage conditions. This means that private law is not the same as public law.
For both, no electricity mix should be used for heat pumps, as this has been politically set to zero.

And with an annual performance factor (COP) of 2, where do you stand?

For optimistic annual performance factor values, you can refer to the Fraunhofer study.
What actually comes out of it can be seen on YouTube from the "Energiesparkommissar."
“Zukunft Altbau” posted a video one month ago for energy consultants.

Hydrogen storage is far too expensive and, like electric vehicles, is only a luxury for many.

In the end, everything will depend on electricity prices, because the average consumer does not have five- to six-figure savings.

That is why it is important to use modern heat pump systems and not have every slow-selling model still being sold at double the price, as is the case now.
Photovoltaics and battery storage don’t even need to be mentioned at the moment, unless you already have a Rolex on your wrist and a Porsche as a second car.
However, they contribute far too little to heating and are therefore excluded from current funding under the KfW efficiency house program.

Or in other words, the key principle for new construction is to save energy.
This is achieved through the building envelope and smart usage.
The heating load remains the same, regardless of the type of energy source used.