ᐅ Geothermal Heating or Condensing Gas Boiler?

We have chosen the two energy sources mentioned above as our favorites. Now we need to decide which is suitable for us. Our house is about 143m² (1,539 sq ft).

What would you recommend? What are the pros and cons of each? Are there any details on average operating and installation costs? Lifespan, etc.?

Thank you.

The heat generator is best determined based, among other things, on an energy performance certificate (HLB). This way, you know the heating demand and can decide which heat generator is most suitable.

In principle, both of the heat generators you mentioned should work for a modern new build. There are individual conditions for each (e.g., soil conditions/space for a ground source heat pump – gas connection availability for a gas condensing boiler) that speak for or against one or the other option.

If both are feasible, it usually comes down to personal preference regarding the heating method; economically, there is little difference between the two.

MrDuncan schrieb:
What would you advise us to do?

It depends on the investment costs. If gas is significantly cheaper than geothermal energy, I would choose gas. Are you building in an area covered by the Energy Saving Ordinance and the Renewable Energy Heat Act? That could negatively affect the use of gas.

It’s more a matter of belief... With gas, you have lower initial costs... but higher operating costs... with a heat pump, it’s exactly the opposite...

You should consider that BAFA offers a subsidy of 4500 € (about $): (if the calculated annual performance factor is greater than 4.5). The heating comparison page might also be helpful.

The calculation is actually quite simple: gas costs you 5 cents per kWh, electricity 20 cents per kWh. So a heat pump (by geothermal, do you mean a brine heat pump?) needs to achieve at least a seasonal performance factor of 4 to avoid being more expensive in operating costs. That could work. But it will probably be difficult for the higher initial investment to pay off.

You should also always keep in mind how low the heating demand of a modern house is. For 143 sqm (about 1540 sq ft), you should come in under 10,000 kWh of heating demand. That results in 500 € (about 500 USD) annual gas costs / 42 € (about 42 USD) per month. What savings could you realistically expect from that? Even if a brine heat pump uses only half of that. The ROI is still far away...

If, of course, you mean the "Iceland version" of geothermal, meaning you have a hot spring on your property, that would be a jackpot. Then you would only have to pay for the electricity for the circulation pumps and that’s it.

Best regards,

Andreas