Cheapest Way to Heat a House in Spain (2026)
Most homes in Spain already have the cheapest heating system installed. They just don’t use it properly.
The cheapest way to heat most homes in Spain is by using a modern air conditioning unit in heating mode. With current electricity prices, it typically costs between €0.025 and €0.033 per kWh of heat, significantly lower than gas, pellets, or electric heaters.
Real heating costs in Spain (updated monthly)
We calculate the true cost of heating by factoring in both the price of the fuel and the efficiency of the system.
Electricity calculations use the Octopus Relax tariff from our live tariff database. Last updated: 2026-04-27.
Heating Cost Comparison
Based on electricity tariff: €0.098/kWh (Updated 2026-04-27)
| Heating Method | Efficiency | Cost per kWh (Heat) | Est. Monthly Cost |
|---|---|---|---|
| Air Conditioning (Heat Pump)Lowest Cost | 300% - 400% (COP 3-4) | €0.033 - €0.025 | €8.58 |
| Olive Wood Stove | 75% | €0.052 | €15.56 |
| Pellet Stove | 87% | €0.123 | €36.78 |
| Butane Gas Bottle | 90% | €0.115 | €34.41 |
| Electric Heater | 100% | €0.098 | €29.40 |
Relative Cost per kWh of Heat
Why air conditioning is so cheap to run
Many people assume that because air conditioning uses electricity, it must be expensive. This is true for standard electric heaters, but air conditioning works differently.
Modern AC units are heat pumps. Instead of burning fuel or using electrical resistance to create heat, they move heat from the outside air into your home. This process is incredibly efficient, resulting in a Coefficient of Performance (COP) of 3 to 4.
1 kWh of electricity in → 3 to 4 kWh of heat out
Spain’s climate is a massive advantage here. Because winters are generally mild (especially on the coast), there is plenty of ambient heat in the outside air for the system to extract, keeping the COP very high.
How to Use Air Conditioning Efficiently for Heating in Spain
The most efficient way to use air conditioning for heating in Spain is to set it between 20°C and 22°C and leave it running steadily. Setting higher temperatures or turning it on and off repeatedly increases electricity use and reduces efficiency.
What Temperature Should You Set Your AC To?
For most homes in Spain, the optimal heating temperature is:
- 20°C to 22°C for living areas
- 18°C to 20°C for bedrooms
This range balances comfort and efficiency.
Every degree above 22°C increases energy consumption significantly, often by 6–10% per degree.
Setting your AC to 26–28°C does not heat your home faster. It simply forces the system to work harder for longer, increasing your electricity bill.
How Temperature Affects Cost
Slide to see how setting your AC higher impacts your electricity bill.
Why Setting a Higher Temperature Costs More
Air conditioning systems work most efficiently when maintaining a steady temperature. When you set a very high temperature:
- The system runs at maximum output for longer
- Efficiency (COP) drops slightly under heavy load
- The room often overheats, then cools again
- This creates repeated cycles of high energy use
The result is higher electricity consumption with no real comfort benefit.
Is It Better to Leave the AC On or Turn It On and Off?
In most cases, it is cheaper to maintain a steady temperature than to turn the system on and off.
Turning the AC off allows the property to cool down fully. When you turn it back on, the system must work harder to bring the temperature back up. This “catch-up heating” is inefficient and often costs more overall.
A steady 20–21°C uses less energy than repeatedly heating a cold room back to 24–26°C.
✓Best Efficiency Checklist
- •Set temperature between 20°C and 22°C
- •Use “Heat” mode, not “Auto” if possible
- •Keep doors and windows closed
- •Clean filters regularly
- •Use ceiling fans on low speed to circulate warm air
- •Avoid extreme temperature settings
✗Mistakes That Cost Money
- •Setting temperature too high (25°C+)
- •Turning the system on only when cold
- •Using electric heaters instead of AC
- •Running on an expensive tariff
- •Blocking airflow or dirty filters
Your Settings Matter, But Your Tariff Matters More
Even when your air conditioning is set correctly, your electricity tariff still has the biggest impact on your running costs. A poorly chosen tariff can double the cost of heating your home, even with an efficient system.
When this works best
- ✓Coastal Spain: The mild winters keep the COP extremely high.
- ✓Existing split units: Using what you already have installed requires zero upfront investment.
- ✓Good electricity tariffs: A low fixed rate or a well-managed time-of-use tariff.
When you need alternatives
- ✗Cold inland areas: When temperatures drop near freezing, air source heat pumps lose efficiency.
- ✗Poor insulation: In very drafty homes, AC air can escape quickly, making radiant heat (like radiators) sometimes feel more comfortable.
- ✗Undersized systems: A small bedroom unit cannot effectively heat a large open-plan living space.
Are pellets really cheaper than electricity?
At current prices, pellet heating can cost up to 4–5 times more per kWh of heat than an efficient air conditioning heat pump on a good tariff. The idea that pellets are the "budget" option is outdated.
Heating with electricity? Your tariff matters.
Upload your bill and we’ll compare over 50 tariffs in Spain to see if you’re overpaying. A bad tariff can double your heating cost.
Upload your billRelated heating guides for Spain
Heating costs depend on the system, the property, and the tariff. These guides explain the most common comparisons in more detail.