Solar system, yes or no?

Hello,

A mistaken assumption, because these heat pumps "live" off the energy of the installation room. Where does that energy come from? Just have an energy balance calculated. In addition, the coefficient of performance hardly exceeds a value of 2. "Normal" air heat pumps achieve > 3.5!

Regards

Anyway, I have such a unit in the basement. It runs from April to October. During this time, I don't need a drop of oil. The electricity consumption is almost exactly 10 euros per month. Therefore, this thing doesn't draw energy from the installation room. It doesn't run in winter anyway. The purchase cost was around 3,500 euros. My heating oil consumption has been clearly reduced as a result. A solar system costs many times as much and usually supplies me with hot water only when I don't need it.

Regards

Hello, solar systems are in my opinion the general term and include solar thermal systems and photovoltaics. v.g.

That's correct. However, Matze66 clearly wrote about a photovoltaic system - that's not what this is about at all. Regards

The electricity consumption is pretty much exactly 10 euros per month.

€ as a unit of energy is somewhat unfortunate.

With a COP of 2 and 0.20 €/kWh, one can assume a thermal energy demand of 100 kWh/month. With a modern gas condensing unit and 0.05 €/kWh, this would amount to 6.25 €/month; with a real air heat pump, 5.7 to 6.6 €/month. An older oil boiler at 0.06 €/kWh would lead to 12 €/month here.
The latter is a difference to the exhaust air heat pump of 2 €/month. With 7 months of use per year, this results in savings of 14 €/year on an investment of 3,500 €.
A truly sensible investment.

Best regards.

I have such a unit in my basement. It runs from April to October. During this time, I don’t need a drop of oil. The electricity cost is almost exactly 10 euros per month.
Therefore, the thing doesn’t draw energy from the installation room. It doesn’t run in winter anyway.
The purchase cost was around 3,500 euros.
My heating oil consumption has clearly decreased because of it.
A solar system costs a multiple and usually only provides me with hot water when I don’t need it.

Regards

Thank you for this opinion! I also installed a system for hot water at my parents’ place. And the gas consumption has decreased, what more could you want!
CO2 saved, gas saved, and they are satisfied! For 10 years now! The system cost 5,000.00 DM back then, minus subsidies.
I would advise you, BAFA is still offering good subsidies until the end of this year!

@Pendel: Yes, I have had exactly the same experiences. According to the manufacturer, the COB is also over 3. According to "€uro", only at "2". Regards

hi,

may I butt in here? I guess a new post wouldn’t be allowed according to the forum rules anyway.

So: I still don’t quite understand how these solar systems can be used. Only for hot water? Or also to produce electricity for household appliances?

For hot water this wouldn’t be necessary for us. During the day hardly anyone is at home and so far the 7l reserve in our boiler has been enough for washing hands after the toilet. So far we have a boiler with an instantaneous water heater.

But the monthly electricity costs for household appliances/ PCs etc. are quite high.
The new house would be free standing and would always have sun. There are no trees in the way either. But it will probably have a gable roof. Which way should the roof surface face? East? Directly south? I can still plan all that...
Above all I would like to know what kind of system is needed. I can then research or ask specifically about brand and size. Maybe someone knows what they cost. We have an annual electricity consumption of around 5000 kwh (it will be more since I now have my office at home).

Thanks for the food for thought.

Regards Bromi