Gas, electric, or aerothermal: which heats for less this winter?

Natural gas: pros & cons

Natural gas heating has long been the most common option in Spanish homes. It works through a boiler that burns natural gas (or propane in areas without a gas grid) to heat water, which then circulates through radiators or underfloor heating systems.

Some of its main advantages include proven and reliable technology and low cost per kWh, since natural gas tends to be cheaper than electricity. Furthermore, the supply is typically consistent in urban areas with extensive distribution networks, which means many residences are already equipped with gas installations. Another benefit is its strong heating capacity, which allows large spaces to warm up quickly and evenly.

However, there are several drawbacks. The system relies heavily on fossil fuels for its heating capacity —natural gas is a non-renewable resource— and the associated CO₂ emissions result in a less sustainable choice. While emissions are lower than those from other fossil fuels, it is still polluting. You’ll also need to install a boiler, which must be inspected regularly. Finally, gas prices fluctuate based on international markets, which can increase household energy bills.

Electric heating: pros & cons

Electric heating systems convert electricity directly into heat through technologies such as radiators, storage heaters, heat pumps, or electric underfloor heating.

This option offers a few advantages that might suit your needs. For instance, its installation is straightforward, requiring no piping or structural work —just plug it in. It has minimal maintenance requirements with no mandatory inspections. As it is highly sustainable, it produces no direct emissions (no combustion or gases). Furthermore, if the electricity comes from renewable sources, it can be 100% clean. Moreover, it allows for independent control of each room, so you can avoid heating empty spaces.

Among the disadvantages of electric heating is its high kWh cost —electricity is typically more expensive than gas. The system also depends heavily on electricity market fluctuations, especially during peak hours. This implies that consumption will skyrocket if you use inefficient equipment (like resistance radiators). Finally, its low efficiency in large spaces means it can also be expensive in big, poorly insulated houses.

Aerothermal heating: pros & cons

Aerothermal systems are currently among the most efficient and sustainable heating options. This technology extracts energy from outdoor air using a heat pump, which then provides heating, cooling, and domestic hot water.

Its exceptional energy efficiency —generating 3 to 5 kWh of heat per 1 kWh consumed— leads its many advantages. This way, this system can achieve savings of up to 60% compared to traditional heating systems. It also uses renewable energy by drawing ambient heat, even in winter. Therefore, it produces zero direct emissions and works seamlessly with solar self-consumption (ideal for homes with photovoltaic panels), making your house practically energy independent. Crucially, a single unit provides heating, cooling, and hot water.

The top disadvantage of an aerothermal heat pump is the high upfront cost, ranging between €6,000 and €12,000. Other drawbacks include the need for outdoor space to place the heat pump unit or its fluctuating performance, as it may require electric backup in very cold climates (though it remains more efficient than conventional electric heating). Lastly, it is essential to ensure your home has proper insulation to unlock its full potential.

Which heating system to choose according to your home and usage