CO2 Carbon Footprint Gas Heating vs. Heat Pump in New Buildings

Recently, the idea of installing a gas heating system in a new single-family home in 2025 was discussed among acquaintances (in 2023, according to my source/Statista, about 10% still did this). For this, I (among others together with ChatGPT, o1-preview) did some research and came to results that somehow do not fit the current zeitgeist.

- In a 300 sqm KfW-55 house (minimum standard 2024, energy efficiency class A with 40 kWh/m2/year), the additional CO2 emissions of a gas heating system compared to a heat pump amount to about 1.6 tons of CO2 per year. (Calculation: Gas: 300 m2×40 kWh/m2/year=12,000 kWh/year; 12,000 kWh×0.202 kg CO2/kWh=2,424 kg CO2/year; heat pump - annual performance factor 4.5, German electricity mix 300g per kg CO2: 12,000 kWh/4.5=3,429 kWh/year; 3,429 kWh×0.3 kg CO2/kWh=1,028.7 kg CO2/year => 2,424 kg CO2/year − 1,028.7 kg CO2/year = 1,395.3 kg CO2/year)

- The compensation of 1.6 tons of CO2 costs about 40 euros at atmosfair. 2 tons 50 euros.

- A heat pump costs about 35,000 euros in 2024, a gas heating system about 15,000 euros. (no direct subsidy for heat pumps for new builds).

That means, if I compensate the additional CO2 emissions of a gas heating system for 20 years, it costs me about 800 euros. If I pay 1,000 euros, I have done something good for the environment overall. Compared to this stands an additional acquisition cost of about 20,000 euros for the heat pump. 20,000 euros for a result that I can achieve also with 1,000 euros - that seems disproportionate to me.

Currently, the price per ton of CO2 is about 30 euros, even if the price rises to 400 euros by 2045 (allegedly a worst-case scenario), I am still better off with gas (1.6 tons * 400 euros/ton = 640 euros per year in 2045, before that probably considerably less).

My calculation is of course based on several average values, but if I am not grossly wrong in at least one point, the result seems quite clear: If I install a gas heating system in a new single-family home and at least compensate the CO2 emissions, it looks as if I would be cheaper off and could still do something for the environment from the savings.

Am I missing something? What should additionally be considered? Does the calculation contain a major incorrect assumption / wrong average number?

PS: I have seen the thread about gas heating systems 23/24, but in my opinion the topic of CO2 footprint was not discussed there and towards the end the thread in my opinion anyway drifted away from the actual topic.

What else would need to be considered?

More and more heat pumps are being installed, the share of gas heating is decreasing, and with it the number of gas customers. The fixed costs of the gas systems are spread over fewer and fewer customers, consequently the gas price rises unpredictably. You always have to buy gas, but you can produce electricity yourself with photovoltaics, or buy it directly from a neighbor with a photovoltaic field (the energy companies are still resisting).

Does the invoice contain a gross false assumption

Yes. Quite simply the one that the compensation payment compensates for something. Once the CO2 has been released, it is out there. You can throw money after it, but the climate doesn't care.

Am I missing something? What else would need to be considered? Does the calculation contain a gross false assumption / incorrect average figure?

Photovoltaics Green electricity contract Exit from CO2-intensive power generation Otherwise. Money does not save a climate or reduce CO2 in the atmosphere. Gas networks are being shut down (some municipalities have even already decided this - relatively short-term).

Gas networks are being shut down (some municipalities have even already decided this - relatively short notice).

For example Mannheim MVV until 2035

So because this has come up twice now and amazes me. To my knowledge, CO2 can very well be removed from the atmosphere again, for example trees do that, to name the most obvious thing - reforesting forests. Otherwise, I also consider other CO2 compensations to be quite valid, but I didn’t want to start a discussion about that now.

I consider photovoltaics to be a valid point, although in my opinion that does not completely change the calculation in favor of the heat pump. It certainly depends on the individual case, how large the photovoltaic system is, what other electricity consumption one has. But yes, point taken, it could/should be taken into account.

The gas network is of course also a point, although one could use an underground gas tank and be independent with it.