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This is a text for all those whose coffers are full because they could not or did not want to spend any money in times of Corona.
And who at the same time call a house their own.
You don't even have to be interested in climate protection.
Because a solar system pays off one way or another.
More precisely: the photovoltaic system.
For a decade, it was in great demand among clever investors because the sun and the Renewable Energy Sources Act (EEG) together provided a guaranteed return.
But that had the blemish that other electricity customers had to pay for it.
Over the years, private individuals have installed more than a million household solar roofs on their homes.
Almost 20 billion euros were invested in new photovoltaic systems in 2010 alone.
Some investors felt a little guilty about it, at the latest when they noticed that poorer people, pensioners and tenants were also paying for their profit through the price of electricity.
At the same time, more than 2,000 large companies were largely exempt from the so-called EEG tax on their electricity price - such as gravel pits, feed factories, aluminum huts, slaughterhouses such as those of Tönnies and Westfleisch or the Gilde brewery.
Different governments decided that quite unanimously, because they did not want to put companies at a disadvantage in EU competition.
But instead of using tax revenues for these subsidies, private electricity customers were simply allowed to pay more.
To the author
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Financial tip
Hermann-Josef Tenhagen
, born in 1963, is editor-in-chief of »Finanztip«.
The money advisor is part of the non-profit Finanztip Foundation.
»Finanztip« is refinanced via so-called affiliate links.
More about it here.
Tenhagen was previously editor-in-chief of the “Finanztest” magazine for 15 years.
After studying politics and economics, he began his journalistic career at the »daily newspaper«.
Today he is an honorary member of the supervisory board of the cooperative.
Tenhagen writes weekly on SPIEGEL.de about how to handle one's own money properly.
In the meantime, however, the world of solar systems is back in order.
Because solar power can now be produced at prices that are drastically below the purchase price for electricity customers.
Your own potential profit is no longer based mainly on an allowance that others have to pay.
With a properly planned system, you can use 30 percent of the solar power generated on your own roof - without any extras.
The installer certainly offers a corresponding energy manager that makes this possible.
The self-generated and used electricity costs between 10 and 14 cents per kilowatt hour - depending on where you live, the size of the system and the orientation of the roof.
The electricity from the electricity company costs 30 cents.
A family in Berlin who needs 4600 kilowatt hours (kWh) of electricity per year can save 400 euros with the corresponding solar system due to the price difference when buying electricity.
On top of that, there is still 250 euros a year for the electricity, which the family can sell to the electricity company for just under 8 cents per kilowatt hour.
This price is lower than your own costs - and closer than before to the price that the energy supplier would have to pay for electricity from coal or other fuels.
The family then pays for the costs for the system and its operation after about twelve to fourteen years, if the system was inexpensive.
And a system like this can be set up quickly: after good preparation, it doesn't take more than a day on a neat tiled roof.
Increase personal use
But that is only the beginning.
Clever solar pioneers can really increase their own use.
On the one hand, by buying a power storage unit and placing it in the basement or garage.
Such a large battery can store too much solar power generated during the day for use in the evening.
Then you can finally cook with solar power in the evening or watch TV at night.
Unfortunately, the batteries for the solar power probably don't last as long as the solar panels on the roof (20 years) - at least the manufacturers don't want to guarantee that.
And they are still not really cheap.
However, many federal states help with the purchase of such battery storage systems: Baden-Württemberg, Bavaria, Berlin, Lower Saxony, Rhineland-Palatinate, North Rhine-Westphalia and Saxony subsidize the devices if you buy them with the solar system.
Thuringia even subsidizes solar panels and battery storage.
There are also a few municipal funding programs.
And this aid is not passed on to the electricity price like the EEG allowance, but financed from tax revenues.
Heat with electricity
And there is a second way to use more ecologically generated electricity.
Namely for heating.
When I was young, heating with electricity was considered the ecological sacrilege.
Water is boiled in gigantic atomic piles or coal-fired power plants.
To generate electricity with the steam.
So heat turned into electricity.
And the night storage heater is heated with the electricity.
So electricity converted back into heat.
The conversion losses are considerable.
But the model was offered because the nuclear reactors were running and could produce more electricity at night than was needed.
In a certain way, heating with electricity also subsidized nuclear power.
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Today it can be done much more intelligently.
The electricity is no longer used directly for heating.
It only drives the heat pump, with which homeowners can obtain the heat they need for heating from the ground or, in this country, mostly from the ambient air.
The difference: the ambient or geothermal heat is free once the hardware is installed.
And your own solar power is very cheap as soon as the PV system is installed on the roof.
In fact, a completely CO2-free heating system is created in the spirit of the home-owning climate protector.
And even better: it pays off.
In addition, such a system is more forward-looking than the combination of gas heating and solar thermal (solar heating on the roof), which in the end also has to use a lot of fossil natural gas.
Anyone who purchases a new heating system for their own house today would like to be able to rely (quite rightly) on the fact that they have done it right ecologically - also with a view to the next 30 years that this heating system will be running.
We want to be CO2-neutral by 2050 - and not in the form of a sale of indulgences by reforesting forests elsewhere, but by making it here at home.
That must be the claim if you feel like a world power of engineers.
Driving with electricity
The future of mobility has not yet been taken into account: e-cars are probably the best solution for low-carbon transport, at least in rural areas.
Proponents of a traffic turnaround also see it that way.
The routes are longer than in the city, traveling by train is not worthwhile, and there is often no demand for extensive bus services either.
Out in the country, the car remains important, and there are more garages and more solar systems than in the city for electric mobility.
And with their own solar system on the roof and the subsidized special wallbox, e-car owners will in future be able to refuel their cars cheaply themselves.
If the car is always at the office during the day, however, a power storage device would be necessary.
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Those who fill up the car in this way drive more cheaply than with the special and cheaper car electricity that is now also available.
On top of that, KfW also provides 900 euros in funding for the wallbox.
Your own solar power is almost always cheaper than charging at the public charging stations.
Even if car power on the autobahn, at a price of 79 cents per kilowatt hour, is certainly one of the outliers.
Extra goodie from the local petrol station: Nobody takes the petrol station away, even for longer charging times.
Find the right installer
So the principle sounds impressive, but does it pay off?
My colleague Ines Rutschmann says: in principle yes.
But to do this in concrete terms, you have to pay attention to a few things.
Practical tests have shown that the prices for the complete installation of solar systems at the craft businesses differ greatly.
While the modules per kilowatt of power can be bought wholesalers for 200 euros or a little more net, the prices including assembly, substructure, lightning protection, inverter and electrical installation including surge protection ranged up to over 2000 euros per kilowatt of power.
Of course, smaller systems are more expensive per kilowatt of power.
But even with a large system for private use with an output of 9 to 10 kilowatts, the prices determined ranged from almost 1,000 euros per kilowatt of output to over 1,800 euros.
Such price differences pose a dilemma for you as a customer.
Which of the around 900 specialist companies in Germany named for example at the Photovoltaic Forum is the right and inexpensive one for you if you want to build now?
Unfortunately, relying on the installers alone is not such a good strategy.
Our practical test has shown: Some installation companies presented comparative profitability calculations with which they also presented overpriced systems as profitable.
If one reckons with an electricity price increase of 4.5 percent, classic household electricity would cost 67 cents per kilowatt hour at the beginning of the 1940s.
Then practically every system would be a bargain.
That is not realistic, but some craftsmen present such an invoice.
So don't be fooled.
You will achieve your goal with a comparatively simple strategy:
Determine the size of your system.
How much electricity do you need a year?
You know the current consumption.
In addition, there could be at least 3000 kWh per year for an e-car with a mileage of 15,000 kilometers.
And for an average insulated house with 150 square meters of living space, around 6000 kWh for the heat pump for heating.
The differences are still huge here.
And air source heat pumps usually need significantly more electricity than geothermal heat pumps.
Check the necessary roof area.
You probably need around seven square meters of roof area for your panels per kilowatt of power.
Plan your system so that you install around one kilowatt of power for every 1000 kWh of forecast electricity consumption.
(You can find data for a more precise estimate in our guide.) The best way to do this is of course with a solid tiled roof, easily accessible for scaffolding, with an unshaded south side and a roof pitch of 30 degrees.
West and east are also possible, but are less effective, just like a different roof pitch.
The consumer centers offer a suitability solar check as a control.
Compare prices, it's gotten easier.
Get a range of offers for your photovoltaic system from good, specialized Internet portals.
(After our investigation at Finanztip, I recommend photovoltaik-angebotsvergleich.de and selfmade-energy.com).
Then you know what is currently going on in terms of price.
If you do not have all the money in your account: Bank loans for solar systems are not difficult to obtain and inexpensive for an installment loan.
The cheapest option, however, is financing through KfW at your house bank.
The interest on the 270 credit line is currently a good 1 percent.
And if you have a favorite installer nearby, ask them too.
Let him know that you have already made yourself familiar with the portals, then you will hopefully get a competitive price from him.
And then get started with the solar future.