KFW40 House Project 2020 *Planning Ideas*

With your KFW40 and the standard outdoor temperature, you can easily achieve an annual performance factor between 4.55 and 4.60 with an air-water heat pump at 30 degrees flow temperature.
Anything else does not make economic sense and you also get 30% funding. You will never recoup the additional costs.

Edit:
Just saw that you did not write the standard outdoor temperature. It should be between -10 and -12 according to my statement. Otherwise, we would have to take another look.

-11.49

With your KFW40 and the standard outdoor temperature, you can easily achieve an annual performance factor between 4.55 and 4.60 with an air-to-water heat pump at 30 degrees flow temperature.

Unfortunately, this is a misconception.
Especially then, the domestic hot water share is significantly higher than, for example, in a house built to energy saving ordinance standards.
And thus the annual performance factor is lower.

That is correct. With a reduced annual operating number and estimated additional costs of 50 euros per year, the deep drilling has then paid off in 200 years.

Contact elbehaus, they have built us a good affordable KfW40 house in the suburban area, and you can organize the + yourself... Ytong + insulation.

Check out the construction fairs. Visit model parks, for example, there is a large one in Werder. Get a price quote from Town & Country. And from Scanhaus Marlow. Then take a look at the BLBs.

Then you can better assess what’s what. Committing now to a specific brick and heating system makes less sense.

You can also overdo it..

There are several options for geothermal energy extraction (costs estimated!):
And has not explicitly excluded any of them at first

[*]Drilling = €10,000
[*]Trench collector self-installation = €3,000
[*]Trench collector by company = €7,000

However, there are:

[*]Subsidy (BAFA) = €4,500
[*]Cost savings per year = approx. €120

Regarding the annual costs (under 2.) I roughly estimated:

[*]Final heat consumption per year KfW40 = realistically 6000 kWh
[*]Air-water heat pump (seasonal performance factor 3.5) = 1714 kWh -> electricity price €0.3/kWh = €514/year
[*]Brine-water heat pump (seasonal performance factor 4.5) = 1333 kWh -> electricity price €0.3/kWh = €400/year

Whereby consumption is usually somewhat higher in the first years (moisture in the house etc.) and thus the savings from geothermal energy should be slightly higher.

The acquisition costs will roughly balance out, although you will probably pay €1,000-2,000 more for the brine-water heat pump.

Thus, there are additional or lower costs for the brine-water heat pump compared to the air-water heat pump ranging from €7,500 to -€500 (depending on the method of geothermal extraction)

If you want to exaggerate, you could also calculate how long the average "lifetime" of the devices is and that you can continue to use the brine source if the heating system needs to be replaced – but I’ll leave that aside here
(Roughly speaking, brine-water heat pumps probably last longer than air-water heat pumps because the technology for a brine-water heat pump is located in a dry, temperature-controlled basement/laundry room.
Of course, this promotes longevity.)

However, precise data is missing regarding an exact cost breakdown.
Viewed over 20 years, it is probably a zero-sum game. (Depending on the method of geothermal extraction)