Refurbishment and modernisation tips

Air in radiators or in the entire heating system - often recognisable by gurgling or whistling noises - prevents even heat dissipation. The result: radiators do not heat up properly and the heating system works inefficiently.

Regular venting can improve the heating performance. Rooms warm up more quickly and energy consumption can be reduced. You can usually simply bleed the trapped air out of the radiator yourself using a bleed spanner.

Clear, step-by-step instructions on how to bleed radiators are easy to find on the internet, for example on the website of the German Consumer Advice Centre.

A room temperature that is too high or remains constant over a long period of time often leads to unnecessary energy consumption. Lowering the temperature by just one degree can reduce heating energy requirements by around six per cent. By consciously adjusting the thermostats - for example by lowering the temperature at night or lowering the temperature in rooms that are not used very often - energy consumption can be reduced significantly. Programmable thermostats help to automatically adjust the room temperature to the time of day and habits.

Leaky windows and doors mean that warm air continuously escapes to the outside and cold air enters. This is often noticeable through draughts and increases the need for heating. Such heat losses can be significantly reduced with simple measures such as sealing strips or brush seals. The measures are usually inexpensive and can be implemented by yourself without much effort.

Uninsulated heating pipes continuously give off heat to the environment as they pass through unheated rooms such as basements or attics. This heat is lost for the actual room heating and unnecessarily increases energy consumption.

This heat loss can be significantly reduced by retrofitting insulation to the heating pipes. Prefabricated insulation shells made of plastic or mineral wool can usually be easily fitted by yourself and are available from specialist retailers. It is important that the insulation is fitted without gaps, especially at pipe connections and bends.

Professional pipe insulation ensures that the heat is directed to where it is needed and helps to improve the efficiency of the heating system and reduce heating costs.

Older circulation pumps often operate at a constant output and consume an unnecessary amount of electricity. Modern high-efficiency pumps automatically adjust their output to the actual demand. Replacing them can therefore reduce both electricity consumption and heating costs. In many cases, the investment is amortised after just a few years.

Digital or smart thermostats enable automatic and needs-based control of the room temperature. For example, the heating can be lowered when nobody is at home and raised again in good time before rooms are used. This increases comfort and prevents unnecessary energy consumption at the same time.

A lot of heat is lost through an uninsulated top storey ceiling, as warm air rises upwards. Retrofitting insulation can significantly reduce this heat loss and is often inexpensive to implement compared to other insulation measures. It is therefore a very effective energy-saving measure.

In many older buildings, radiators are located in wall recesses, which are often less well insulated than the rest of the outer wall. As a result, some of the heat is lost directly to the outside. By installing insulating material behind the radiator, this heat loss can be reduced and the efficiency of the heating system improved.

If you still have an older hydraulic instantaneous water heater installed, it is worth taking a closer look. By replacing it with a modern hydraulic-electronic or fully electronic instantaneous water heater, you can save up to 30 % electricity. Electric instantaneous water heaters work more efficiently, heat the water evenly and maintain a constant temperature. In combination with an economy shower head, additional costs can be saved.

In many buildings, radiators are supplied with heat unevenly because the heating system is not optimally adjusted. As a result, some rooms are overheated while others do not get warm enough. With hydronic balancing, the heating system is adjusted so that each radiator receives exactly the amount of heat it needs. This improves the efficiency of the system and can significantly reduce energy consumption.

A buffer cylinder stores excess heat from the heating system and makes it available on demand with a time delay. This allows heat to be generated more evenly and efficiently. Particularly in heating systems with fluctuating heat generation - such as wood heating systems, heat pumps or solar thermal systems - a buffer cylinder can help to reduce energy consumption and increase the service life of the system.

However, buffer storage tanks are not always present in existing buildings, especially in older gas or oil heating systems. Whether a retrofit makes sense depends heavily on the heating system in question and its design. Specialist advice is therefore recommended in order to check the benefits and dimensions on an individual basis.

Solar thermal systems utilise the sun's energy to heat water and support the heating system. This can reduce the need for fossil fuels. Particularly in the summer months, a large part of the hot water requirement can be covered by solar energy.

With a solar panel system, you can generate electricity on your own roof. For small to medium-sized systems, or solar panel systems without storage, the investment is usually less than 10,000 euros. For tenants, there are also many ways to harness the sun’s energy, such as tenant-generated electricity schemes, communal building energy supply, or their own solar panel system on a leased roof area.

Uninsulated external walls are one of the biggest causes of heat loss in buildings. Retrofitting façade insulation can significantly reduce energy requirements. At the same time, the indoor climate improves as the interior walls remain warmer and the risk of moisture and mould formation is reduced.

As warm air rises upwards, a lot of energy is lost through an uninsulated roof. Comprehensive roof insulation can significantly reduce this loss and make a major contribution to lowering heating energy requirements. The measure can often be sensibly combined with a planned roof renovation.

Old or single-glazed windows allow a lot of heat to escape and can cause draughts. Modern windows with multiple glazing and good seals significantly reduce heat loss by up to 60 % or more. At the same time, they improve living comfort and sound insulation. It often makes sense to replace all windows at the same time. Alternatively, they can be replaced in stages to minimise the financial burden.

Outdated heating systems often work inefficiently and cause high energy consumption. Switching to modern heating technologies - such as heat pumps - enables a much more efficient and climate-friendly heat supply. This utilises environmental energy, which reduces costs and CO₂ emissions in the long term.

An Individual Renovation Roadmap (iSFP) helps property owners to plan the energy-efficiency modernisation of their building step by step. It highlights which measures are appropriate, the order in which they can be implemented, and the potential savings involved. This allows investments to be planned for the long term and coordinated effectively.

Further information on the Individual Renovation Roadmap (iSFP) can be found, for example, on the Consumer Advice Centre’s website.

A qualified energy consultation analyses the energy status of a building and identifies specific weak points. On this basis, individual measures are recommended that are both technically sensible and economical. In addition, an energy consultation is often a prerequisite for the utilisation of subsidies.

In many municipalities, centralised heating networks are being expanded to efficiently supply several buildings with heat. A connection can be a good alternative to an in-house heating system, especially if renewable energies or waste heat are utilised. This can reduce both emissions and maintenance costs.

By combining several measures - such as insulation, window replacement and heating modernisation - a building can be gradually developed into an efficiency house. The aim is to significantly reduce energy consumption while maintaining a high level of living comfort. This type of refurbishment requires good planning, but offers the greatest long-term savings potential.