CO2 Emissions from Heating Systems: How to Protect the Environment and Save Money

September 3, 2020
  1. What is CO2?
  2. Heating with oil and gas is harmful to the environment
  3. How much CO2 does your heating emit?
  4. Renewable energies pay off in the long term
  5. Reasons for a system change
  6. Alternative 1: Heat pumps
  7. Alternative 2: Wood heating systems
  8. Alternative 3: District heating
  9. Alternative 4: Solar energy
  10. Subsidies for energy-saving measures
  11. Use energy and heat intelligently

Heating consumes around two-fifths of the energy in Switzerland and is responsible for around one-third of our total CO2 emissions. With climate-friendly heating (and good thermal insulation) you are doing something good for the environment, the climate and your wallet.  

What is CO2?

Carbon dioxide is the chemical compound of carbon and oxygen with the molecular formula CO2 and is partly responsible for the greenhouse effect. Carbon dioxide is produced, for example, when fossil fuels such as coal, oil or natural gas are burned. Since industrialisation, the CO2 concentration in the atmosphere has risen by almost 50 percent. Around two thirds of global warming is caused by CO2.

Heating with oil and gas is harmful to the environment

The share of oil heating and heating oil consumption have been falling in Switzerland for years. Nevertheless, only Luxembourg in Europe consumes more heating oil per capita than we do. 60 percent of our buildings are heated with oil or gas, in Sweden it is only 6 percent. Half of all oil heating systems that need to be replaced are replaced by new oil or gas heating systems that emit climate-damaging CO2.


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How much CO2 does your heating emit?

The comparison for an average single-family house with an annual heating energy demand of 14,400 kilowatt hours shows how differently heating systems impact the climate (source: WWF Switzerland):

  • Oil heating: 4680 kilograms of CO2 per year
  • Gas heating: 3650 kilograms of CO2 per year
  • Solar collectors combined with gas: 3190 kilograms of CO2 per year
  • District heating: wide range, but low CO2 emissions
  • Wood pellet heating: 710 kilograms of CO2 per year
  • Air-source heat pump: 490 kilograms of CO2 per year
  • Ground-source heat pump: 380 kilograms of CO2 per year

Calculate CO2 emissions from heating systems
With the heating calculator you can calculate the CO2 emissions and compare your heating with other systems.

Houzy Hint


With our free heating calculator you can calculate how much CO2 your heating system emits. You need to collect a few data and can then compare your system with other heating systems.

Renewable energies pay off in the long term

Why do so many homeowners replace their old heating systems with new oil or gas heating systems when fossil fuels pollute the environment so much? Some because it is easier to replace a heating system 1:1. Many because they think heating with oil or gas is cheaper. This is true in the short and medium term, because the investment costs for a heating system with renewable energy are higher. Especially if, for example, the heating system and the oil tank have to be dismantled first.

In the long term (time horizon 20 years), however, it is worthwhile to heat with renewable energies because the operating costs and especially the energy costs are lower. Heat pumps, for example, are usually maintenance-free and use electricity for less than 1,000 francs a year to heat an average single-family house. The energy costs for a comparable oil heating system are at least twice as high. And with the total revision of the CO2 law, heating oil would have to become more expensive, then heating with renewable energies would pay off even faster than today.

Calculate heating costs and compare with other heating systems
With the heating calculator you can work out the annual costs and total costs in 20 years.

Houzy Hint


With our heating calculator you can also calculate the annual costs and total costs in 20 years of your heating system and compare it with other heating systems - free of charge and without obligation.

Reasons for a system change

Most people who replace their oil or gas heating with another heating system want to protect the environment, save the climate or save money in the long term. But there are other good reasons. For example, heating with renewable energies should not only maintain the value of your house or flat, but increase it in the medium to long term. Furthermore, after the total revision of the CO2 law, it should become more difficult to sell a house or flat with an old oil heating system.

Houzy Advice

Good to know

The replacement of an old heating system is considered value-preserving for tax purposes. This means that you can deduct the expenditure from your taxable income in your tax return. It makes sense to spread the investments over two tax periods and thus break the progression of income tax. This saves taxes.

Alternative 1: Heat pumps

The investment costs of heat pumps are high, but their operating costs are low. Heat pumps produce 3 to 5 times as much thermal energy as they draw from the air, the ground or the water. Ground-source heat pumps cost more than air or water heat pumps, but require up to a third less electricity.

  • Low to no CO2 emissions
  • Zero CO2 emissions with solar energy, hydropower or wind energy
  • Simple and efficient operation
  • Inverter heat pumps adapt their output to the demand
  • Heat pumps combined with energy refurbishments are particularly sensible

CO2 emissions from heat pumps are minimal
The climate impact of heat pumps is minimal. That is why they are an investment in the future.

Alternative 2: Wood heating systems

Heating with pellets, logs and woodchips has little impact on the climate. The CO2 that is produced during combustion is bound because in Switzerland only as much wood may be felled as will grow back. Piece wood heating systems are suitable for single-family homes, pellet heating systems for single-family homes and apartment buildings with condominiums. The supply would have to find space in the former oil tank room.

  • Low to no CO2 emissions
  • Wood heating systems are almost CO2-neutral
  • Minimal air pollution from nitrogen oxides and particulate matter
  • High security of supply in densely forested Switzerland
  • Regional energy promotion and value creation

Alternative 3: District heating

District heating networks are widespread in Switzerland. They consist of one or more heat centres. These pipe hot water through insulated pipes into the house, where it is distributed to the individual rooms or flats via heat exchangers and pipes.

  • Low to no CO2 emissions
  • Simple and efficient operation
  • High security of supply
  • Little space required in the cellar

Alternative 4: Solar energy

Solar thermal systems heat water. Their core piece is the so-called absorber, a black metal body with channels through which water circulates. This water absorbs solar heat and transfers it to the hot water tank via the heat exchanger. Such systems need an alternative heat generator to be able to heat water in the storage tank even in winter or during long periods of bad weather. With solar collectors on the roof, the solar system can complement another heating system, the most suitable being wood heating.

  • Low CO2 emissions
  • Ideal as CO2-free support for heating systems with renewable energies
  • Solar thermal systems relieve heat pumps and store solar heat
  • A solar thermal system covers at least 30 percent of the annual energy demand

Reading tip: "Solar energy: Is my roof suitable for a solar system?"

Solar energy supports and relieves other heating systems
4 to 6 m2 of solar collector surface are enough to cover two thirds of the hot water needs of a family of four.

Subsidies for energy-saving measures

Enter the postcode of the building location - and you will receive a listing of all energy promotion programmes in Switzerland. The search includes promotion programmes of the cantons, cities and municipalities as well as campaigns of regional energy supply companies.

Use energy and heat intelligently

Regardless of the heating system, you can reduce your energy consumption and thus your CO2 emissions with three simple measures:

  1. Warm air must circulate. Therefore, do not cover the radiators with furniture or curtains. If you close the shutters or window blinds at night, the rooms cool down less.
  2. Tilt windows that are open all day waste a lot of energy and only marginally improve the air quality. It is better to ventilate three times a day for five to ten minutes. This way, less heat escapes, and cross-ventilation also improves the air quality.
  3. Regulate the temperature with the radiator valve, thermostatic valves are the most efficient, and set your comfortable temperature in each room. Warmest in the living area, coolest in the bedroom. These are guideline values and not generally applicable specifications:

  • 22 degrees in the bathroom
  • 20 degrees in the living area
  • 18 degrees in the bedroom and hallway

Houzy Advice

Good to know

If you increase the room temperature by 1 degree, your heating costs increase by 6 percent on average.

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