FAQ Photovoltaics: Professional answers to your questions

If you don't ask, you remain ignorant - or read our FAQ! First of all, let's take a look at photovoltaic systems. This much in advance: solar power makes double sense, both for your wallet and for the environment. But the devil, as always, is in the detail... Here you can find out what participants of a webinar of our partner RaiffeisenCasa wanted to know about the topic - and how the professionals, including Liiva employees, answered.


Which investments around the home are also worthwhile financially? Liiva supports you in maintaining or even increasing the value of your home.

Does the investment in solar systems pay off?

Yes. Photovoltaic modules today are only 5% of the cost of 20 years ago. Of course, the return on investment has to be looked at carefully in each individual case: It depends on the project, the location and the electricity company. But above all, a photovoltaic system gives you the good feeling of using renewable energy.

Do I need equity capital for the installation?

As a rule, yes. It depends on exactly what your financial situation is, and in particular the loan- to-value ratio and affordability.

How long does a photovoltaic system last?

The photovoltaic cells are always embedded in a "glass sandwich" and glass lasts almost indefinitely. What can happen is hail damage, but this is very rare (like with cars). Moreover, they are covered by the building insurance.However, the efficiency of the cells decreases over time. One should expect a 10% reduction in yield after 10 years and 20% after 20 years. According to current knowledge, the cells will function for at least 30 to 35 years.

Are contributions for retrofitting a photovoltaic system regulated nationwide - or cantonally? Do they also apply to second homes?

They apply to all types of houses. The situation is relatively inconsistent, so it is worthwhile to find out exactly. Details can be found at and via the so-called federal and cantonal building programme.

Can the energy produced be stored?

Yes, with batteries. These are becoming more powerful and cheaper every year. The best battery, by the way, is an electric car: you drive with the stored energy "for free" and, above all, you feel good about driving with electricity from renewable energy sources.

How does a so-called ice store work?

Ice storage systems make very efficient use of physics. When the state of aggregation changes from water to ice, the stored energy corresponds to a difference in water temperature of 80°C. When the ice thaws into water, this energy is released again.

The ice storage tank is part of the heating system and stores heat. It normally works with thermal solar collectors. Thus, it does not have anything to do directly with the photovoltaic system. Batteries are needed to store the electricity.

How can several parties benefit from a joint investment?

Today, anyone can operate their own solar power plant with their own system. The model is called ZEV (Zusammenschluss Eigenenergieverbrauch). You can therefore also sell the electricity to the neighbouring flat. This requires a private meter and the tariff is regulated by the state and is within the range of approx. +/- 2 centimes per kilowatt hour compared to the electricity company tariff.

The feed-in tariff from a private photovoltaic system is sometimes lower than if the electricity is purchased from an energy service provider. Why?

The cost-covering feed-in tariff (KEV) was abolished because people want the electricity they produce themselves to be used primarily for their own homes and not necessarily to flow into the public grid.You can take advantage of this: Run the washing machine when the sun is shining and not at night as in the past with the cheaper low tariff. Smart controls, water storage tanks, etc. also make it possible to run the heating during the day. Systems are developing rapidly and batteries are becoming around 10% cheaper every year - a good option for storage for own use.

Is the energy contribution from the electricity company taxable?

Yes, it is income. The installation of the equipment, on the other hand, is partially or fully tax deductible.

When does an in-roof system make sense?

Mounting a PV system on old bricks is a mistake: the service life of the elements does not match.Another important keyword is "dual function". It means the following: Photovoltaic modules form the roof cladding and produce electricity at the same time. Use this opportunity to better insulate the roof. In this way, you also reduce the energy demand and increase comfort at the same time.

Now it's up to you

What would you like to know about photovoltaics for your modernisation project? Send us your questions! We will be happy to answer the questions received and perhaps even include them in another round of the FAQ.

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