HoisleBauer22
2022-03-07 21:56:58
- #1
I would like to return to my calculation once again.
Note: For 20 years that means: about €2,800 (at 40->35) or about €5,600 (at 40->30) savings vs. €3,375 - 4,500 (15-20€/m²) extra costs.
Can it be assumed that the energy savings at 40->35 (10-12.5%) is proportional to 40->30 and then applies as 20-25%?
I wonder: Where does the value of 2-2.5% savings per degree even come from?
An attempt at calculation:
If I assume 55 kWh/a m² heat demand and 225 m² area (including the basement even though it is not living space!), that makes 12,375 kWh per year. With an annual performance factor of about 4, that would be 12,375:4 = 3,094 kWh electricity consumption. Assuming electricity costs of 45 cents per kWh, that makes around €1,392 in electricity costs. So with 10% energy savings (about 2% per degree) due to a lower flow temperature (35 degrees), I would save about €139. The investment would have paid off after about 24 years. Probably not even, because my electricity/heat demand would be covered by photovoltaic to 30%, and then electricity costs = savings would be smaller.
Note: For 20 years that means: about €2,800 (at 40->35) or about €5,600 (at 40->30) savings vs. €3,375 - 4,500 (15-20€/m²) extra costs.
Can it be assumed that the energy savings at 40->35 (10-12.5%) is proportional to 40->30 and then applies as 20-25%?
I wonder: Where does the value of 2-2.5% savings per degree even come from?