ᐅ CO2 Footprint of Gas Heating vs. Heat Pumps in New Construction

Recently, there was a discussion among acquaintances about the idea of installing a gas heating system in a new single-family house in 2025 (according to my source/Statista, about 10% still did this in 2023). I researched this topic somewhat (including with the help of ChatGPT, o1-preview) and came across results that seem somewhat out of step with the current general attitude.

- In a 300 sqm (3,230 sq ft) KfW-55 house (minimum standard for 2024, energy efficiency class A with 40 kWh/m2/year), the additional CO2 emissions from 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 300 g CO2/kWh: 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)

- Compensating 1.6 tons of CO2 costs about 40 euros on atmosfair. Two tons cost 50 euros.

- In 2024, a heat pump costs roughly 35,000 euros, while a gas heating system costs around 15,000 euros. (There is no direct subsidy for heat pumps in new builds.)

That means, if I compensate the additional CO2 emissions from a gas heating system over 20 years, it costs me about 800 euros. If I pay 1,000 euros, I have still done something positive for the environment overall. On the other hand, there is an upfront cost difference of about 20,000 euros for the heat pump. Spending 20,000 euros for an outcome I can achieve with 1,000 euros seems disproportionate to me.

Currently, the price per ton of CO2 is about 30 euros; even if this price rises to 400 euros by 2045 (allegedly a worst-case scenario), I would still come out cheaper with gas (1.6 tons × 400 euros/ton = 640 euros per year in 2045, and likely significantly less before that).

Of course, my calculation is based on various average values, but unless I am seriously wrong in at least one area, the result seems quite clear: If I install a gas heating system in a new single-family home and at least compensate for the CO2 emissions, it appears I come out cheaper and could still do something good for the environment with the savings.

Am I missing something? What else should be considered? Does the calculation contain a major incorrect assumption or wrong average value?

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

Konsument4 schrieb:

What else should be taken into consideration?

More and more heat pumps are being installed, while the share of gas heating systems is decreasing, along with the number of gas customers.
The fixed costs of gas installations are spread over fewer and fewer customers, which makes the gas price increasingly unpredictable.
You always have to buy gas,
whereas you can generate your own electricity with photovoltaic systems or directly buy it from a neighbor with a photovoltaic array (energy companies are still resisting this).

Konsument4 schrieb:

Does the invoice contain a fundamental misunderstanding

Yes. Quite simply, the compensation payment does not actually compensate for anything. Once the CO2 is released, it is out there. Throwing money at it does not affect the climate.

Konsument4 schrieb:

Am I missing something? What else should be taken into account? Does the calculation include a major incorrect assumption or a wrong average figure?

Photovoltaics
Green electricity contract
Exit from CO2-intensive power generation

Otherwise, money does not save the climate or reduce CO2 in the atmosphere. Gas grids are being shut down (some municipalities have already decided this, even on relatively short notice).

nordanney schrieb:

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

For example, Mannheim MVV by 2035

Since this has come up twice now and surprised me: to my knowledge, CO2 can indeed be removed from the atmosphere, for example, trees do this—just to name the most obvious example—by reforesting. Otherwise, I also consider other forms of CO2 offsetting to be quite valid, but I didn’t want to start a discussion about that here.

I think photovoltaics are a valid point, although in my opinion that doesn’t completely tip the balance in favor of heat pumps. It definitely depends on the individual case, such as the size of the photovoltaic system and one’s overall electricity consumption. But yes, noted, it could or should be taken into account.

The gas network is also a consideration, although one could use an underground gas tank and thus remain independent.