How much% does the waste heat from electrical lighting and electr. Devices such as laptop / TV in winter contribute to the heating power of the actual heating?
A heater for a house has between 15 and 30 kW
As more and more lights are switched to energy-saving bulbs,
a bulb only needs 4 - 8 watts instead of 60 watts.
A laptop also requires relatively little, i.e. A power supply has only 40-70 watts. All together there will be approx. 200-250 watts.
Now put 20 kW in relation to 200 W then you are at 1% heating output
That depends on the construction of the house and the heat requirement.
In the case of a passive house, the waste heat from the residents and devices is clearly included in the heat balance.
In principle, all electronic energy in the house is converted into heat. The heating period is only around 6 months. This means that only 50% of the waste heat can be used.
Consumes an old house:
6000 kWh / a electricity (3000 kWh in the heating phase)
4000 kWh / a gas for hot water
30,000 kWh of gas for heating, the proportion is 3,000 / 33,000 = 9.1%.
In a passive house, the proportion of heat for heating is significantly lower. The percentage is then higher there.
We should first know the heating output. There are two ways to determine them:
One measures the fuel consumption per unit of time and multiplies it by the respective calorific value (for oil, gas and the like), or
The heat demand is calculated using an online heat demand calculator on the web based on the structural conditions (building materials and room dimensions).
The heating power of the electrical devices is equal to their power consumption, i.e. The "power consumption" per time. It can be read on the electricity meter. This should be done over several days to get an average.
Both sizes can be determined in the unit kWh per hour = kW. Then the proportion of heat generated by the electrical devices can be calculated.
Alright, or do you have any questions?
Rather not at all, it is often so small that hardly anything would arrive except maybe from the pc who is around for hours, but that also turns off when it gets too hot for him!
Usable waste heat is returned to the boiler, which is only possible for Dan who came who is suitable for it! So rather only what you still heat with high temperatures then you can still get the heat out of the smoke, for example. But I doubt that with 40 or 50 degrees is still possible!
