Solar Energy: Harnessing Heat from the Sun via Solar Water Heating Systems

Solarthermie, a system that converts sunlight into heat and hot water, is gaining popularity as an environmentally friendly and cost-efficient energy solution. This system can cover about 60% of a household's hot water needs and approximately 25% of its heating needs.

Installing a solar thermal system offers several advantages. It presents a savings potential for heating, contributes to environmentally friendly energy production, is a free energy source, and may qualify for state funding. However, it's important to note that the savings can vary depending on factors such as building insulation, hot water consumption, and household technology used.

A solarthermie system can store energy for later use with a thermal solar system and a storage tank. This means you can have hot water and heat even when the sun isn't shining.

However, there are some disadvantages to consider. High investment costs, the need for an additional heating system, possible renovation work required, energy yield dependent on weather, and a suitable roof area being a prerequisite are factors that potential users should be aware of.

The financing costs for a solar thermal system in a multi-family house generally range between approximately 8,000 and 20,000 euros, depending on whether it is used for warm water only or also for heating support. For a single-family house, a solarthermie system with a storage tank can cost between 5,000 and 15,000 €.

Financing options are available for those looking to invest in solar thermal energy. KfW offers loans and redemption subsidies for the complete renovation of an old house to an energy-efficient house and for the new construction of a particularly energy-efficient building under Programmes 261 and 297. A private renovation loan can also be used to finance a solar thermal system and can be combined with state funding programs.

For the purchase and installation of a solar thermal system, you can apply for a grant from the state promotional bank KfW through program 458, with a maximum of 70% of the costs. The supplementary loan from KfW (Program 358, 359) is available for homeowners with a taxable household income less than 90,000 €, with a maximum loan amount of 120,000 € per residential unit.

The cost of a solarthermie system depends on factors such as the type of collectors, size of the hot water storage tank, location, and sun orientation of the house, and renovation measures. It's crucial to consider these factors when calculating the economic viability of solar thermal energy.

In conclusion, solarthermie offers a sustainable and cost-effective solution for heating and hot water needs. While there are initial investment costs, the long-term savings can offset these costs. The economic viability of solar thermal energy needs to be calculated precisely, and potential users should weigh the savings against the acquisition costs.

Solarthermie can be combined with other heating systems, such as heat pumps, pellet heating, and gas heating, as a hybrid solar system. With the falling prices of solar modules in 2023 and 2024, solarthermie is becoming an increasingly attractive option for homeowners looking to reduce their carbon footprint and lower their energy bills.