Geothermal energy or gas condensing boiler?

Have chosen the two aforementioned energy sources as favorites. Now it is time to decide what is suitable for us. We have approx. 143m². What would you advise us? What are the pros and cons? Are there any information about average operating and acquisition costs? Lifespan, etc.?

Thank you very much.

The heat generator is best determined, among other things, based on an HLB. Then you know the heat demand and can decide which heat generator fits best.

Basically, both heat generators you mentioned could work in a modern new building; for both, there are individual conditions (e.g., soil conditions/space for a brine heat pump - gas connection available for a gas condensing boiler) that argue for or against either generator.

If both are feasible, it is usually a matter of preference how to heat; economically, both are about the same.

What would you advise us?

It depends on the investment costs. If gas is significantly cheaper than geothermal energy, I would choose gas. Are you building within the scope of the Energy Saving Ordinance and the Renewable Energy Heat Act? That could affect the gas issue unpleasantly.

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

You should take into account that you can receive a subsidy of €4500 from the BAFA for geothermal energy (if the calculated annual performance factor >4.5). Maybe the heating comparison page helps as well.

The calculation is actually simple: gas costs you 5 cents/kWh, electricity 20 cents/kWh. So a heat pump (do you mean a brine heat pump by geothermal energy?) must achieve an annual performance factor of at least 4 to not be more expensive in operating costs at least. That could work. But the higher investment costs will probably be difficult to recover.

One should always keep in mind how low the heat demand of a modern house is. With 143 sqm, you should come out at under 10,000 kWh heat demand. That means 500 € cost for gas per year / 42 € per month. What do you want to save much more there? Even if a brine heat pump then needs only half. The ROI is far away....

If of course you mean the "Iceland version" of geothermal energy, that is, you have a hot spring on the property, that would of course be the jackpot. Then only the electricity costs for the circulation pumps are incurred and that's it.

Best regards,

Andreas