Why Spanish houses are so cold — and how to heat them

You moved to sunny Spain. It's January, it's 8°C outside — and somehow it's colder inside your living room than your old house up north ever was. You're wearing a coat indoors. You are not imagining it, and you are very much not alone. There are solid, almost logical reasons Spanish homes are cold, and once you understand them, fixing it gets a lot cheaper.

Wait — why is my house in Spain so cold?

The short answer: Spanish homes are designed for the enemy that lasts five months, not the one that lasts six weeks. On most of the coast the real battle is the brutal summer, so homes are built to stay cool — and the same features that shrug off August heat make January miserable.

Four things stack up:

1. They're built to keep heat out. Thick masonry walls, tile or terrazzo floors, high ceilings, shady orientation and shutters (persianas). Brilliant for summer. In winter that same thermal mass sits cold and radiates it back at you.

2. Little or no insulation — depending on when it was built. This is the big one, and it's a matter of building codes:

Spain's first thermal-insulation rule only arrived in 1979; proper modern standards came with the 2006 Building Code (CTE). Millions of coastal holiday homes date from the 1960s–90s construction boom — the top two rows. That's why the cold feels structural. It is.

3. No central-heating culture on the coast. In cold interior and northern Spain (Madrid, Castilla, the north), central heating is normal. On the Costa Blanca, Costa Brava and Costa del Sol many homes have no fixed heating at all — just portable gas heaters, plug-in electric radiators, or a reverse-cycle air-con unit the owner only ever used for cooling.

4. Damp makes it worse. Coastal homes without heating or ventilation get damp, and damp cold feels far colder than dry cold — plus it breeds mould. It's why the house can feel colder than the temperature outside.

And the neat irony: "how do Spanish houses stay cool in summer?" and "why are they so cold in winter?" have the same answer. The design that wins in August loses in January. If you have just bought the place, the first winter is usually the shock — our guide to setting up electricity in Spain after buying a house covers the contract side of that same handover.

The cold-house paradox: warm country, coldest homes

Here's the data point almost nobody expects. The European countries where people most struggle to keep their homes warm are not the freezing ones — they're the warm ones.

Share of the population unable to keep their home adequately warm (Eurostat, 2024):

Spain sits near the top; Finland, where winter is a real adversary, sits at the bottom. The reason is exactly what we just covered: warm-climate housing is built without winter in mind, energy costs are high relative to incomes, and the buildings are unrenovated. Finland builds for the cold and heats properly; Spain historically did neither.

It shows up in mortality, too. Southern European countries — Spain included — have higher excess winter death rates than Scandinavia, a pattern researchers have documented for decades. Populations used to mild winters live in homes and bodies less prepared for the cold snaps that do come. The mild climate is precisely why the cold is dangerous: nobody built for it.

Is it actually unhealthy to live in a cold house?

Yes — and this isn't hand-waving. The World Health Organization's Housing and Health Guidelines set a minimum healthy indoor temperature of 18°C, with 20–21°C recommended for the elderly, young children and the unwell. That 18°C is a floor, not a comfort target.

What happens as the thermometer drops:

Cold makes blood vessels constrict, which raises blood pressure and makes the heart work harder — the mechanism behind those winter cardiovascular numbers. Cold, damp homes also drive respiratory problems and mould, and there's good evidence linking cold housing to anxiety and depression.

Is it unhealthy to sleep in a cold room? A cool bedroom is fine — roughly 18–21°C is ideal for sleep. A genuinely cold one (below ~16°C) isn't: it raises overnight blood pressure and disturbs sleep, and it's hardest on the vulnerable. Aim to keep humidity in the 30–50% range too, which keeps both mould and that bone-deep damp chill at bay.

(This is general information, not medical advice.)

How to make a cold Spanish house warmer

You don't have to renovate to feel a difference. Work from cheapest to biggest:

Free / near-free

• Close persianas and curtains at dusk to trap heat; open them on sunny days to let the winter sun in.
• Draught-proof doors and windows — old Spanish windows leak badly. Self-adhesive foam strips cost a few euros.
• Put rugs on tile floors. Cold hard floors are a huge comfort drain.
• Ventilate in short bursts at midday (5–10 minutes), not by leaving windows cracked all day.
• Heat the room you're in, not the whole house — and heat the person (blankets, layers) before the air.

Under ~€100

• Thermal or lined curtains and door draught excluders.
• A dehumidifier — drier air feels warmer and stops mould. Often the single best comfort-per-euro buy on the damp coast.
• Reflective panels behind any wall-mounted heaters.
• Secondary-glazing film on single-glazed windows.

Bigger investment (owners)

• Roof or loft insulation — usually the highest-impact upgrade for the money.
• Double glazing.
• A reverse-cycle heat pump (see below), which is also your cheapest running heat.

If you renovate more than 25% of the thermal envelope you must meet the current Building Code anyway — a natural moment to insulate properly. External insulation (SATE) runs ~€80–120/m² of façade; internal insulation ~€40–60/m², typically paying back in 5–10 years. If you are already planning works on the roof, it's worth reading our solar panels in Spain guide first: a heat pump running on your own midday generation is the cheapest winter heat there is.

The cheapest way to heat: the comparison that surprises everyone

Most people, feeling cold, buy a plug-in electric radiator. It's the single most expensive way to heat a Spanish home — and the fix is often already bolted to the wall.

Here's why. What matters isn't the price of the fuel; it's the price per unit of useful heat, which is fuel price ÷ efficiency. A heat pump doesn't make heat, it moves it, so one unit of electricity delivers three or four units of heat. Every plug-in resistive heater, by contrast, delivers exactly one.

Approximate cost per kWh of delivered heat (assuming ~€0.18/kWh all-in electricity — less on off-peak or indexed tariffs; see what actually drives your bill):

† At the point of use — but a flueless butano or paraffin heater dumps water vapour straight into the room, feeding the damp problem, and carries a real carbon-monoxide risk without ventilation.

A heat pump does draw real power when it starts up, so a home that heats electrically sometimes needs a step more contracted power than a home that doesn't — that is the other half of the story in why your potencia contratada is probably wrong.

What does heating actually cost you? Run the numbers on a space heater and an electric boiler at your own rate — the difference over a winter is usually the argument for a heat pump.

The part most guides miss: your tariff sets the price

If you heat with electricity — and on the coast most people do — then that €0.05 to €0.18 per unit isn't fixed. Your tariff decides it.

Run a heat pump in the expensive weekday-evening peak on the wrong tariff and you erode its advantage. Run it in cheaper off-peak hours, or on an indexed tariff during Spain's cheap solar-flooded midday, and the cheapest heater in the house gets cheaper still. Winter is simply the mirror image of the summer air-con story — see how much air-con really costs in Spain for the cooling half: the same home, the same "am I on the right contract?" question — just with the heat running instead of the cooling.

It's also the fastest thing to fix. Insulation takes an autumn and a budget. Switching to a tariff that fits how and when you heat takes an afternoon — and if you're not sure what your current contract even is, start by reading your Spanish bill.

FAQ

Why are Spanish houses so cold in winter? They're built to keep summer heat out, not winter heat in — thick masonry, tile floors, and little or no insulation in the millions of homes built before Spain's 2006 Building Code. Most coastal homes also lack central heating.

Are houses in Spain insulated? It depends on age. Homes built before 1979 had no insulation requirement at all; meaningful standards only arrived in 2006. Many older coastal and holiday homes are effectively uninsulated with single glazing.

Is it unhealthy to live in a cold house? Yes. The WHO sets 18°C as the minimum healthy indoor temperature. Below that, respiratory and cardiovascular risks rise — steeply below 12°C — and cold, damp homes worsen asthma, mould and mental health.

Is it unhealthy to sleep in a cold room? A cool bedroom (18–21°C) is ideal for sleep. A genuinely cold one (below ~16°C) raises overnight blood pressure and disturbs sleep, and is hardest on the elderly and very young.

What's the cheapest way to heat a home in Spain? A reverse-cycle heat pump (the same unit as a split air-conditioner), which delivers 3–4 units of heat per unit of electricity — roughly three times cheaper per unit of heat than an electric radiator. Pellet stoves are the next cheapest to run.

How do I make a cold house warmer without renovating? Draught-proof, close shutters and curtains at night, put rugs on tile floors, run a dehumidifier, and heat the room you're in with a heat pump rather than the whole house with electric radiators.

How do Spanish houses stay cool in summer? The same features that make them cold in winter: thick walls and thermal mass, tile floors, shutters, shade and cross-ventilation. Homes here are optimised for the long hot season, not the short cold one.

HolaSwitch is an independent electricity comparison and switching service, funded by affiliate commissions when you choose to switch through a partner provider. We never handle your contract or send your data to providers. This article is general information — not medical, construction or financial advice.