As we continue on the path to energy transition, the energetic renovation of old buildings is high on the EU's agenda. The majority of German households consist of older buildings that clearly have a lot of catching up to do in terms of their energy efficiency. Old building materials from times before the first energy ordinance in 1979 do not even come close to meeting today's standards. In addition, many properties have damaged windows, facades or roofs, which causes additional energy loss.
The full energetic renovation of an old building includes not only the insulation of the aforementioned elements, but also a modern heating system and the supportive use of innovative smart home technology. Although an energetic renovation is associated with considerable costs, these are quickly recovered because of the often-significant energy savings. State subsidy programmes or loans with repayment subsidies are intended to make it easier for property owners to renovate their old building to make it more energy-efficient, thereby helping to achieve the goals of the energy transition.
The energetic renovation of an old building is always about reducing energy consumption. Around 75 percent of existing buildings in Germany were built before 1979. An energy ordinance and an associated awareness for choosing suitable building materials did not yet exist in the past and post-war period. Nevertheless, these buildings do not inevitably require complete modernisation in order to improve energy efficiency and living comfort. Individual measures such as replacing windows or purchasing a new heating system with a heat pump for renewable energies can already result in significant savings. This is especially true if the property has already been renovated in the past. But if the building is poorly insulated, renovating the building shell should be a priority. Because even the best heating is of little use if the heat literally goes out the window. An individual building renovation roadmap serves to plan an energetic renovation with a view to reducing energy consumption. However, it also takes into account the individual needs and preferences of the occupants as well as the renovation budget.
For properties completed before 1 February 2002, it is mandatory to undertake an energetic renovation at the latest upon sale, if the property does not meet the required standards, such as the minimum thermal insulation according to DIN 4108-2 g. Buyers have two years to implement the necessary measures after moving in. Due to this energetic renovation requirement, prospective buyers should take a close look at the energy certificate of a property. They should also take into account the costs for an energetic renovation that will arise in the subsequent two years when deciding to buy and add them to the purchase price. Common measures include, for example, replacing the heating system, improving the insulation of the roof or alternatively the attic ceiling as well as the piping.
Oil and gas heating systems with standard or constant temperature boilers may only be in operation for 30 years. Then they must automatically be refurbished or replaced. This does not apply to other and modern heating systems.
If you own an old building, you don't have to renovate your property with every change in the law. This applies in particular to owner-occupied properties with a maximum of two residential units. But once you start implementing a measure, you must do so in a way that complies with the latest legislative requirements. Exceptions to this are, for example, facade renovations due to damage that does not affect more than ten percent of the area.
There are many different materials and methods for renovating an old building to make it more energy efficient. Generally, each property should be assessed individually to determine the best option. Specially trained energy efficiency experts conduct a detailed analysis of a property and its energy shortcomings. The energy consultation is eligible for funding, as is an individual building renovation roadmap, which is why property owners should make use of it. This is because, in principle, energy-related renovation measures should not be looked at separately, but as part of the overall result.
In a so-called NetZero house, for example, the property produces as much energy with the help of a photovoltaic system as it consumes on an annual average. Projects such as Energiesprong rely on serial renovation measures with pre-produced components in order to realise the goals of the European energy transition more quickly. Because up to now, an energetic renovation is only as good as the workers who carry it out. For this reason, most funding programmes only support professionally carried out renovation work and no DIY work.
The use of smart home technology, by the way, achieves demonstrable energy reductions with little effort. Digital aids such as smart heating thermostats or smart home lighting reduce energy consumption through automated control.
Refurbishment of a fossil fuel heating system by replacing the condensing boiler or renewing the heating pump
Replacement with modern heating system for renewable energies
Additional solar thermal energy on the roof
Insulation of the basement ceiling
Exterior wall insulation with curtain wall
Exterior wall insulation with an external thermal insulation composite system
Core insulation between the masonry
Interior insulation of the facade
Window renovation or replacement
Smart home technology such as heating thermostats or smart lighting
Statutory obligation or voluntary renovation measures on an old building - both have obvious energetic advantages. Insulating facades and roofs, replacing leaky windows and installing modern building technology create a much better indoor climate and achieve significant energy savings for the property. A photovoltaic system on the roof also turns property owners into electricity producers. The so-called NetZero house is intended to generate as much electricity on an annual average as it needs for heating, hot water supply and lighting.
The interesting advantages of renovating an old building
Lower energy consumption not only reduces costs, but also protects the environment. Carbon emissions are lower and the energetically renovated old building contributes to the energy transition. Moreover, renovated old buildings look better and offer a higher quality of living for tenants and owners alike. Usually, this also improves burglary protection, especially when smart door locks and new windows are installed. Where thermal insulation is used, this will reduce both moisture damage and noise transmission. This makes the living space more quiet and pleasant to live in.
At the same time, energetic renovation dramatically increases the value of a property. A house or apartment upgraded to a contemporary standard allows higher rents and better sales prices to be realised on the real estate market. Depending on the condition of the old building, the reduction in energy costs is so significant that the savings quickly amortise the expenditure for the energetic renovation. When switching from fossil to renewable energies, the property owner frees himself from the constant price increase of scarce resources and the fluctuating market prices. The renovation of old buildings also reduces the maintenance costs of a property, as the new building components extend the renovation intervals.
The possible disadvantages of an energetic renovation
The energetic renovation of an old building does not only bring advantages. If the apartments have been let, the renovation measures will inconvenience the tenants. In combination with the worry of a subsequent rent increase, this often leads to a hasty move-out. For larger apartment buildings or housing associations, serial renovations such as Energiesprong can reduce the disruption to just a few days. Of course, the inconvenience of a temporary construction site in and around the owner-occupied property also affects the homeowner during a renovation. If the commissioned contractors do not work conscientiously or there are endless delays, trouble is inevitable. Depending on the financial situation, the costs of an energetic renovation can prove to be a burden, at least temporarily. Nevertheless, the advantages outweigh most of these disadvantages. Landlords can allay tenants' fears by guaranteeing them a fixed rent for a certain period of time and involving them in the planning of the renovation measures from the very beginning. Once the tenants become aware of the many advantages and the associated increase in living comfort, almost all of them will patiently accept the renovation measures.
The Federal Funding for Efficient Buildings ("Bundesförderung für effiziente Gebäude", BEG) offers two models for funding the energetic renovation of an old building. If you have enough financial resources to pay for the measures immediately, you will be paid the KfW grant 461 directly if you meet the requirements. Otherwise, KfW grants low-interest development loans with a repayment subsidy. This means that the subsidy is deducted from the loan at the end and hence not the entire amount borrowed has to be repaid. Terms of between four and 30 years with grace periods in the first one to five years are designed to make it easier for property owners to renovate efficiently. KfW subsidises the prior expert planning and construction supervision required during the measure by 50 percent if the maximum requirement is met.
If an old building is to be fully converted into an efficient house, KfW offers loans (nos. 261 and 262) with a maximum amount of up to 150,000 euros, and up to 60,000 euros per residential unit for individual measures. The amount of the grant depends on the type of renovation. Generally speaking, the higher the energy savings in the end, the bigger the subsidy. In the case of an individual building renovation roadmap, the repayment subsidy increases by another five percent. For photovoltaic systems, the KfW loan "Renewable Energies Standard 270" is also available, which can be combined with other subsidies. In addition, BAFA and many federal states offer further subsidies under various conditions for the energetic renovation of old buildings. The following repayment subsidies and maximum loan amounts as a total are to be understood as examples, as KfW has a detailed list and additional limits per residential unit:
Efficiency house for listed buildings: 25 % subsidy, maximum loan amount € 120,000
Efficiency house 70 (future minimum standard): 35 % subsidy up to € 120,000
Efficiency house 55 (current minimum standard): 40 % repayment subsidy of max. € 120,000
Efficiency house 40 renewable energy class (highest standard): 50 %, loan up to € 150,000