Themenbeitrag
Energy-efficient renovation: a necessity, but expensive - what can be done?
When it comes to energy, the housing and property industry can be dizzy at times. With the amendment to the German Building Energy Act (Energieeinsparverordnung - EnEV), its short implementation periods and almost unattainable subsidies, the industry is at breaking point. Nevertheless, the rapid rise in energy costs cannot be ignored, nor can the property industry's necessary contribution to the energy turnaround. The fact is that of the almost 19 million residential buildings in Germany, the lion's share of around 12.4 million were built in 1979 or earlier - and are therefore at least 44 years old (source: Statistikportal).
Low refurbishment rates
Renovation rates are also low: ‘According to a 2018 study by the Institute for Housing and the Environment (IWU), the annual modernisation rate for thermal insulation in existing residential buildings averaged around 1% per year between 2010 and 2016. In the older building stock constructed up to 1978, which has a higher energy consumption than residential buildings with a younger construction age, the overall rate was 1.4% per year (Source: Federal Environment Agency).
Construction costs rising rapidly
There is a considerable amount of work to be done on this subject. The topic of energy-efficient refurbishment is further complicated by the potential for side effects, including a lack of available tradespeople and increased construction costs. The Construction Price Index for Residential Buildings indicates a 41% increase in prices for residential buildings between 2010 and 2021. The price of detached and semi-detached houses and condominiums increased by approximately 84% over the same period (Source: Destatis).
However, this does not assist in achieving the goal of the energy transition, as property is a crucial factor in this process. This is also evident from the following statement from the 2023 DENA Building Report:
‘Around 80 % of heat generators use fossil fuels (oil, gas, coal). While the number of oil and gas-fuelled heating appliances and coal-fired systems is on the decline, the number of gas condensing boilers continues to rise.’
Cost of energy efficient renovation
Given the varying energy characteristics of buildings, it is not feasible to make definitive assertions regarding the costs of energy-efficient refurbishment. Typically, the costs associated with refurbishing a building are presented on a per-square-metre basis, though these can vary depending on the specific type of refurbishment undertaken.
Reference: Building
- When was the building constructed?
- What is the condition of the building?
- Has it been renovated in the past?
- How big is the house?
Reference: Residents' ideas
- What refurbishment work needs to be carried out?
- What materials are needed?
- What is the purpose of the refurbishment?
Don't be put off by the high cost, however, as it will pay for itself over time through the savings in heating costs made as a result of the retrofit(s).
Potential funding
The rising cost of energy is prompting people to reconsider their habits. Subsidies can help to reduce refurbishment costs, allowing more refurbishments to be carried out. The following areas can currently be subsidised as part of energy-efficient refurbishment:
- Installation of a new heating system or optimisation of an existing one (if more than two years old)
- Improve the building envelope (insulation, new windows & doors)
- Installation of an energy efficient ventilation system
- Expert advice & design of the refurbishment
- Installation of digital systems to optimise consumption
Source: Energiewechsel.de
The following funding programmes have already been established:
- State subsidies for professional renovation in the form of a one-off payment or a loan
- Regulation of the refurbishment of existing and new buildings through the Federal Efficient Buildings Grant.
- KfW 261: Loan of up to €150,000 for the construction, purchase or renovation of an efficient house.
- BAFA BEG EM: Grants for
- Insulation and new windows or doors (15% of eligible costs)
- Heating based on renewable energy (10-40 %)
- Solar thermal energy (25 %)
Energy-efficient homes
There are also many options for energy-efficient design in new buildings, and the following energy-efficient design concepts can be distinguished
- Plus energy house: A plus-energy house produces more energy than its occupants consume. This is due to optimised insulation and an energy-efficient heating and solar system. The surplus energy can be used later or fed into the public grid. This allows other sectors, such as industry, to use the energy.
- Zero energy house: A zero energy house produces as much energy as it consumes and is therefore energy neutral. It has very good thermal insulation and a high degree of airtightness. Ideally, no external energy is needed for heating or cooling.
- Passive house: A passive house uses passive heat sources such as sunlight or heat recovery from ventilation systems. Optimised insulation means that only a small amount of heat can escape. The house relies solely on existing technologies to insulate and heat the building and is known for maximising energy savings.
- Low energy house: The energy consumption of a low-energy house is significantly lower than that of a building constructed in accordance with current building energy legislation. In fact, it uses around 45% less primary energy overall. This is due to better insulation of the roof or facade and the installation of double-glazed windows.
Energy transition
In light of the challenges and associated costs, it is imperative that the cost spiral does not spiral further and faster, particularly in consideration of the tenants, who are already under considerable financial strain due to additional increases in the cost of living and inflation. It is not feasible to implement strict rent increases as a solution. While the path to enhanced climate protection is challenging and the measures are not cost-free, they are imperative. All stakeholders are now aware that achieving a virtually climate-neutral building stock by 2050 is a formidable task that must be addressed collectively. It is also evident that measures will only be accepted if there is no sense of disadvantage.
Climate smart control of buildings
What, then, is the solution? Energy-efficient refurbishments should be accompanied by smart digital measures. Climate-smart solutions that enable active control of consumption in buildings, in addition to measurement, are an option that can be implemented quickly and have a positive impact on profitability, energy efficiency and climate protection. Concrete applications could be
Smart thermostats
The key to success here is to implement low-investment, immediately effective solutions with a significant impact. Smart thermostats, for instance, can be integrated with existing heating technology and are quick to install. A recent study by the Karlsruhe Institute of Technology (KIT) has confirmed the effectiveness of these solutions.
The study, entitled "Energy saving potential (heat) for tenants through the use of smart radiator thermostats", examined the consumption of several buildings over a period of three months in winter 2022/2023. Two of the buildings were partially equipped with smart thermostats, while one was not equipped with such technology. The study yielded the following result: A comparison of relative heat consumption revealed that households equipped with smart thermostats exhibited an average reduction of 31.5% in their relative heat consumption. In comparison to the building consumption of the previous five years, the savings of equipped apartments are, on average, 15.5% (adjusted for weather factors and the general, situational savings effects caused by the energy price shock of 2022).
Smart meters (gateways)
It is important to consider smart meters in conjunction with smart meter gateways, as this is an area that should not be underestimated. They facilitate precise recording and control of electricity consumption. From the tenant's perspective, monitoring electricity consumption and adjusting it if necessary is important. From the grid operator's perspective, making better predictions is important. The "Law on the Restart of the Digitization of the Energy Transition" (GNDEW) is designed to streamline the installation of intelligent electricity metering systems, reducing bureaucratic hurdles and accelerating the process. The law was approved by the Bundesrat on 12 May 2023.
The growth of renewable energy sources, the increased adoption of electric vehicles in the transportation sector, and the rising use of heat pumps in buildings are driving the need for a more intelligent integration of electricity generation and consumption. The future energy system will require greater flexibility and will therefore become more complex. The introduction of smart meters and digitisation of the energy transition will be essential to meet this challenge.
As of 2025, the installation of smart meters will be mandatory for households with an annual electricity consumption of more than 6,000 kilowatt hours or a photovoltaic system with more than seven kilowatts of installed capacity. The deadline for equipping them is 2030. Another incentive is that, from 2025 at the latest, all consumers who use smart meters will benefit from dynamic tariffs. Consumers will have the option to purchase electricity when it is available at a lower cost, given the high renewable energy generation at that time. "This benefits not only consumers, but also the market and grid stability," states the Federal Government. (Source: Federal Government)
Conclusion
A lot can be achieved in the field of energy efficiency and climate protection with little investment. The most important thing is that tenants are not overburdened financially and that they play an active role, for example by being able to see their own consumption and possibly even control it directly and consciously. This is made possible by accompanying tools such as app solutions for smart thermostats or smart meters. The fact that tenants would like to have more leeway in this respect is shown, among other things, by the GdW study "Living Trends 2040": Here, 61 percent said that climate-conscious behaviour was very important to them. 61 per cent also consider it important that their landlord is committed to sustainability. (Source: GdW)
For example, the common task of energy transition is still a mammoth task, but it will become manageable together and step by step.
