Condominium ownership - Renovation fund and value of a share
- 3 min read
- 01.07.2026
Energy-efficient refurbishments - what you need to know
For existing properties in particular, upgrading the heating system is now a key issue that should be given high priority, even during the purchase process. In addition to personal values with regard to environmental protection and sustainability, future legal requirements, especially, are an important consideration. These are based on the model cantonal energy provisions (MuKEn 2014), which individual cantons are progressively incorporating into their energy laws.
According to the current targets set by the cantonal energy directors, when replacing oil or gas heating systems, at least 10% of heating requirements must in future be covered by renewable energy sources or saved through additional thermal insulation. At the same time, as is often the case with political processes, the exact scope and transitional arrangements vary, depending on the canton. One thing is certain, however: replacing fossil-fuel heating systems will entail higher requirements and additional investment in the future. Consequently, modernisation projects are often delayed or only individual components, such as burners or control systems, are replaced.
Emergency replacement of a heating system becomes more difficult after the regulations have been implemented, as increasing regulations make quick solutions more difficult. All this makes predictive planning all the more important. Your local Engel & Völkers consultant will be happy to help you and can also recommend
specialists.
Legal requirements & objectives
Switzerland is pursuing the goal of zero greenhouse gas emissions by 2050 and thus becoming climate neutral. With this net-zero target, Switzerland is making its contribution to the internationally agreed goal of limiting global warming to a maximum of 1.5°C above pre-industrial times.
The model cantonal energy provisions (MuKEn), which were developed by the Conference of Cantonal Energy Directors, form a key basis for achieving this objective. They serve as a template for the cantons when drawing up their respective energy laws and create consistent framework conditions for buildings right across Switzerland. The MuKEn represent the lowest common denominator of cantonal energy policy and aim to implement the federal government’s energy strategy through coordinated measures.
A key focus is on increasing the energy efficiency of buildings and gradually reducing the use of fossil fuels in heat generation. The current cantonal energy laws are largely based on MuKEn 2014. New MuKEn have since been adopted, in 2025, and are now being gradually incorporated by the cantons into their own law. For homeowners, this means that the requirements for heating systems and energy-efficient refurbishments will continue to increase in the coming years.
Which properties are affected?
The legal requirements are primarily aimed at older existing buildings with poor energy efficiency – in particular, buildings with insufficient thermal insulation and correspondingly high oil or gas consumption. They primarily affect private owners of single-family dwellings and owners of apartment buildings.
If a building has little or no thermal insulation, additional requirements apply when replacing the heating system: either fossil-fuel consumption needs to be reduced by at least 10% or at least 10% of energy requirements need to be met from renewable sources. This generally leaves owners with two options:
1. Modernise the oil or gas heating system and improve the building’s energy efficiency
Anyone who wishes to continue relying on oil or gas as an energy source for the time being will generally have to replace their existing heat generator with a modern and more efficient heating system. In addition, energy efficiency improvements can be made to the building itself – for example, by installing new windows or additional insulation on the façade and roof. This can significantly reduce fossil-fuel consumption and ensure that the required minimum values can be reached.
2. Switching to renewable energies
Alternatively, the existing fossil-fuel heating system can be partially or fully replaced with a renewable energy system. The aim is to cover at least 10% of energy requirements from renewable sources. Various solutions are available for this, such as heat pumps, wood-fired heating or solar systems.
Buildings that have already undergone energy-efficiency refurbishment or are well insulated will, in many cases, be less affected by the new requirements.
It’s important to remember that Note that the specific minimum requirements may vary from canton to canton. It is therefore essential to check the applicable cantonal regulations carefully in each case.
Assessment and first steps
To assess whether your building is affected by the legal requirements, it is advisable to consult an expert – such as a heating engineer or a specialist in modern heating systems – at an early stage. These experts usually arrange an on-site visit and take a close look at the local conditions. This involves a comprehensive assessment of the existing heating system and the building’s structural condition – much like a medical checkup.
Priority is given to determining whether alternative heating solutions are technically and economically feasible at all. In order to be correctly sized, modern systems, especially heat pumps, require information on both the previous energy consumption levels (current state) and the quality of the building envelope. On the basis of the energy performance figures, it is also possible to determine the required heating output and assess the existing heat distribution – particularly with regard to the required flow temperatures for heat pump systems.
Furthermore, it is essential to obtain an official cantonal building energy certificate (GEAK). This forms a key basis for the energy-efficiency assessment of the property and supports further planning of refurbishment steps.
As a rule of thumb: buildings built after 1990 or refurbished properties from the 1960s to the 1980s – especially those with upgraded windows, façades or roofs – often achieve GEAK category D or better. Properties that meet the Minergie standard are generally well above this and always rate better than category D.
GEAK as a basis for assessing energy efficiency
The cantonal building energy certificate (GEAK) is a standardised document, used right across Switzerland, that presents the energy performance of a property in a transparent and comparable manner. In a concise format – usually just a few pages long – the GEAK provides information on the energy efficiency of a building and serves as an important basis for making decisions about refurbishment and modernisation measures.
For the certificate, two key areas are assessed:
The efficiency of the building envelope (insulation, windows and heat loss)
The overall energy efficiency, which also takes building technology into account (heating, hot water, lighting and the use of renewable energies)
In addition, the GEAK contains specific recommendations for possible energy efficiency improvements.
Overview of the GEAK Classification
| Category | Efficiency of the building envelope | Total energy efficiency |
|---|---|---|
A | Excellent thermal insulation, windows with triple glazing. | Highly efficient building technology for heat generation and lighting, excellent equipment, use of renewable energy. |
B | New buildings achieve Category B automatically due to legal requirements. | New building standard for envelope and technology, use of renewable energy. |
C | Old buildings with completely renewed building envelope. | Comprehensive renovation of old buildings, mostly using renewable energies. |
D | Retrospectively well and extensively insulated old building, but with remaining thermal bridges. | Extensive renovation of old buildings, but with significant gaps or without renewable energies. |
E | Old buildings with significant improvement in thermal insulation, including new thermal insulation glazing. | Partially renovated old buildings, e.g. new heat generation and possibly new equipment and lighting. |
F | Buildings that are partially insulated. | Buildings with at most partial renovation, use of individual new components or that make use of renewable energies. |
G | Old buildings with incomplete or poor subsequent insulation and outstanding renovation potential. | Old buildings with outdated plant technology and without renewable energies, with great potential for improvement. |
Source: www.geak.ch
GEAK thus provides an at-a-glance overview of a property’s energy performance and its potential for improvement. It serves as a key basis for informed decisions, particularly in the context of a planned heating system upgrade.
Energy rating calculation
The energy rating is a key indicator of the energy consumption of a building. It describes the specific energy requirements and is derived from a combination of factors: the quality of the building envelope, the heating system used, other building technology installations, the local climate, the operating method and individual user behaviour.
To calculate the energy rating, the energy reference area must first be determined. This is the sum of all heated areas of a building that are dependent on heating for their use.
This generally includes all rooms such as living rooms, dining rooms, kitchens, bedrooms, wet rooms and hobby rooms. Heated circulation areas such as stairwells and hallways are also included. However, unheated rooms, such as laundry rooms, boiler and utility rooms, garages and cellars are not part of the energy reference area.
Calculation of the energy rating (Ew)
Total heating requirement (kWh) / Energy reference area (m²) = Energy rating Ew (kWh/m²)
Total heating requirement = heating including hot water
Energy reference area = all heated areas
If the energy requirement for hot water is already included in the heating output, this must be taken into account accordingly in the calculation or deducted from it.
| Building type | Average (kWh/m²) | Optimum (kWh/m²a) |
|---|---|---|
Detached/single-family house | 140 | 80 |
Terraced house | 120 | 70 |
Apartment building | 100 | 60 |
Assessment
If the calculated energy rating is above the relevant optimum value, this indicates that there is potential for improving energy efficiency. As a rule, these target values can only be reached through comprehensive energy-efficient refurbishment. On the other hand, the average values correspond to typical existing buildings without comprehensive energy-efficient refurbishment work.
Heating systems & solar energy
When upgrading your heating system, you can choose from a range of modern heating systems that differ in terms of energy source, investment costs, operating costs and the construction work involved. Choosing the right system depends largely on the local conditions and the technical possibilities offered by the property in question.
Overview of modern heating systems
Air-to-water heat pumps use the ambient energy present in the outdoor air as a heat source. Since no geothermal probes or drilling are required, the construction work and financial outlay are comparatively low.
The technology is particularly widely used, as it can be easily integrated into existing buildings. Purchase costs are moderate, while the operating costs are generally low. In addition, the system produces minimal local emissions and uses what is essentially an unlimited energy source.
Water-to-water heat pumps use heat from springs, lakes or groundwater as their energy source. As with air-source heat pumps, the installation work involved is relatively low level. Water quality is a key factor in determining the operation and maintenance costs, however, and it can only be assessed once the system has been installed. It may also change over time. As a rule, water-to-water heat pumps are more suitable for larger properties. The approval process is time-consuming and not possible with every refurbishment project.
Geothermal heat pumps use heat from underground as an energy source for heating and hot-water production. This requires drilling by specialised companies. This is also a free source of primary energy (heat from the ground), which can be used without producing emissions and involves low energy consumption. The initial costs are comparatively somewhat higher, but the operating costs are minimal. Implementation also depends on geological and legal conditions and is not possible for every property.
Wood is a local, renewable energy source that can be used efficiently and conveniently in modern heating systems. Wood-fired heating systems can also be easily combined with other heat sources. It is also carbon neutral and entails slightly higher initial costs but, as a locally available fuel, it offers low operating costs. It does, however, require slightly more space in the basement than other systems and the maintenance of the system is more complex.
With a thermal network, multiple properties are supplied with heat via centralised energy generation. Instead of individual heating systems for each building, heat is generated centrally and distributed via a pipeline network.
Energy sources include wood chips, pellets, industrial waste heat (e.g. from waste incineration plants) and large heat-pump systems using lake water. The heat is transported to the individual buildings via a district heating network and is then transferred to the internal heating system via a heat exchange unit.
District heating is regarded as a particularly convenient and future-proof solution. It is generally highly efficient, saves space in the building and enables a largely carbon-neutral heat supply based on regional energy sources.
A solar thermal system or a domestic hot-water heat pump with photovoltaic system can also be considered as a recommended addition to heating systems.
1. Solar thermal system
Solar energy systems provide hot water and can also support heating. This is a free source of primary energy (the sun), making it an ideal addition to conventional heating systems (including oil and gas heating). Heating support is possible, but depends on dimensions and location. Energy consumption is low and investment costs are moderate. Solar thermal systems reduce operating costs. However, not every roof is suitable for their installation.
2. Photovoltaic system
In these systems, electrical energy is produced on the roof and used to operate the heat pump and other electrical appliances. The investment costs are moderate but lead to a noticeable reduction in operating costs. Photovoltaic systems cannot be installed on every roof, either. Often, a large proportion of self-generated electricity has to be fed into the public grid. The return rates for unused electricity vary and should be checked.
Upgrade options
As part of energy efficiency requirements, property owners in most cantons have various ‘standard’ solutions at their disposal. These make it possible to meet the legal requirements for replacing fossil-fuel heating systems in different ways – depending on the condition of the building, the technical starting point and the owner's willingness to invest.
The 11 standard solutions under the Energy Act
The 10% renewable energy requirement is achieved with a solar thermal system for heating water.
Wood-fired systems are carbon neutral and are therefore considered to be renewable energy.
Air-to-water or brine-to-water heat pumps generate heat all year round for heating and hot water.
Gas heat pumps combine the advantages of condensing boiler technology with renewable energies. Natural gas/biogas is the primary propulsion energy.
The heat comes from waste incineration, wastewater treatment and renewable energies.
Fuel cell technology, for example, is used to generate both heat and electricity in the home at the same time.
The electricity generated by the photovoltaic system drives the heat pump for hot water production.
Old windows are replaced with new ones with high thermal insulation.
The façade and/or roof are fitted with thermal insulation.
A combined heating system that covers the base load with renewable energies and peak loads with fossil fuels.
A domestic ventilation system with heat recovery is installed.
It’s important to remember that the minimum requirements may vary from canton to canton and must always be checked.
Cost-effectiveness & costs
The choice of heating system should not be based solely on initial costs. Rather, it is essential to take a holistic view of the entire life cycle. In addition to purchase cost, this includes annual energy and operating costs, as well as regular maintenance and servicing.
The basis for comparison is an annual energy requirement of around 4,600 litres of heating oil per year.
| Heating system | Annual energy costs (CHF) | Annual service costs (CHF) |
|---|---|---|
Air-source heat pump | 2625 | 150 |
Ground-source heat pump | 2124 | 150 |
Natural gas | 5063 | 550 |
Heating oil | 5549 | 550 |
Pellets | 3401 | 500 |
District heating | 6260 | 50 |
| Heating system | Purchase costs (CHF) | Total costs per year (CHF) |
|---|---|---|
Air-source heat pump | 2330 | 5135 |
Ground-source heat pump | 2640 | 4914 |
Natural gas | 1456 | 7069 |
Heating oil | 1165 | 7264 |
Pellets | 2330 | 6231 |
District heating | 1625 | 7935 |
Conclusion
From a cost-effectiveness point of view, the geothermal heat pump is, in many cases, the most efficient solution – provided that the geological conditions allow for geothermal drilling and there is suitable space available on the property.
Despite a comparatively higher initial investment, this system features very low operating costs and high energy efficiency throughout its entire service life.
Important note on cost-effectiveness calculations
A sound assessment of cost-effectiveness requires a full cost calculation over the entire service life of the each system. This is the only way to objectively compare the different heating solutions. All costs must be taken into account – especially purchase costs, energy consumption, maintenance and any replacement investments over time. Actual investment costs can vary considerably depending on the property and initial situation and thus have a significant impact on the overall result.
Sources
■ MuKEn – Guide to oil heating systems
■ www.meiertobler.ch/sanierung (in DE/FR/IT only)
■ Assessment of energy consumption, environment and energy (canton of Lucerne)
■ Documents from ‘Renewable heating’ incentive consulting course, Swiss Federal Office of Energy (SFOE), 2019
■ Stefan Pfänder, HVAC engineer (Technical College – HTL), Managing Director and Board Member of Otto Bachmann AG
In collaboration with Marco Iten, iten energy saving gmbh
All information is current as of April 2026 and provided without guarantee.
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