How to save on heating this winter (without being cold)

Heating is, by a distance, the biggest energy cost in a home: in an average Spanish household it accounts for around half of all the energy used over the year. Which means it's also where there's most to gain — and where a small adjustment gets multiplied across the whole winter.

Here's what actually works, ordered from what saves most to what saves least.

Temperature: 19-21 degrees by day, 15-17 at night

This is adjustment number one and the cheapest to make. Official energy-efficiency guidance puts comfort at 19-21 °C during the day and 15-17 °C at night or when there's nobody in.

Every extra degree means roughly 7% more consumption. Going from 23 to 20 degrees is around 20% less spent on heating, all winter long, without buying anything.

And if you're cold at 20 degrees, the cheap answer is clothing: a jumper is worth two or three degrees on the thermostat and never shows up on the bill.

A programmable thermostat is what pays back fastest

Heating the house when there's nobody in it is throwing money away, and doing it by hand never works because nobody remembers. A programmable thermostat — or a smart one, if your boiler supports it — pays for itself in a single season:

• It drops the temperature automatically at night and during the hours the house is empty.
• It brings it back up a while before you get home, so you don't notice the gap.
• It avoids the classic mistake of switching everything on and off abruptly, which makes the system work at its least efficient point.

If you have water radiators, add thermostatic valves: they let you give less heat to the rooms you don't use without touching the boiler. They're cheap and you notice the difference.

Which system uses least

Not all systems cost the same per unit of heat. From most to least efficient:

• Heat pump (air-source heating, or air conditioning with a heating mode). By some way the most efficient option: it delivers several units of heat for every unit of electricity it uses. If you have air conditioning, you already have efficient heating installed and a lot of people don't realise it.
• Natural gas boiler. In most cases it's still cheaper per unit of heat than conventional electricity. If it's a condensing boiler, better still.
• Electric radiators, convectors and thermal emitters. They turn one kWh of electricity into one kWh of heat: no more, no less. Cheap and convenient to install, expensive to run.
• Portable stoves and heaters. The same as the above, but concentrated in one room and with the temptation to leave them on.

Careful with the quick comparison. Gas being cheaper per kWh doesn't mean your bill will come down if you change system: you have to count the cost of the equipment, the maintenance and the standing charges. If your heating runs on gas, the price you pay per kWh depends a great deal on whether you're on the regulated or the free market — we explain that in the TUR gas tariff.

The maintenance that genuinely shows

• Bleed the radiators at the start of the season. A radiator with air trapped inside stays cold at the top and forces the boiler to work harder to heat the same space. It takes ten minutes with a bleed key and a container.
• Don't cover them. A radiator behind a sofa, hidden by long curtains or with a shelf over it loses a significant part of its output. It needs air to circulate around it.
• Service the boiler to whatever schedule the manufacturer specifies. A boiler that's out of adjustment uses more and, above all, is a safety matter.
• Fit a reflective panel behind any radiator on an external wall. It's foil-backed board, it costs very little, and it sends back into the room the heat that was heading out through the wall.

The cheap fixes that save most

Most heat isn't lost through the system, it's lost through the house:

• Draught excluders on doors and windows. It's the best-spent euro of the winter. If you can feel a draught when you run your hand round the frame, that's where your money is going.
• Close the blinds at dusk and draw the curtains. A closed blind noticeably reduces heat loss through the glass.
• Open the curtains on south-facing windows while the sun is out. Free heat.
• Shut the rooms you don't use, and their radiators with them.
• Ventilate briefly and thoroughly. Ten minutes with the windows wide open refreshes the air without chilling the walls. Leaving a window ajar all morning does cool the whole house.

If the property has single-glazed windows or old frames, switching to double glazing is the renovation with the biggest impact — but that's an investment, not an adjustment.

Time-of-use bands, if your heating is electric

On the 2.0TD tariff, electricity doesn't cost the same at all hours, and the evening peak band (18:00 to 22:00 on working days) coincides exactly with the moment everybody turns the heating on.

If you have storage heaters or electric underfloor heating, the saving lies in timing them for the small hours, which is off-peak: they heat cheaply and release the warmth afterwards. With ordinary radiators the margin is smaller, but bringing the heating forward into the standard band and letting thermal inertia cover the peak does work. The exact bands are in electricity prices by time of day.

Keep an eye on your contracted power

Winter is when your contracted power gets tested: heating, oven and hob all at once. If your main breaker trips several times, you've come up short. If it never trips, you probably have power to spare and you're paying a higher fixed charge 365 days a year — how to lower your contracted power.

And if your heating is electric and runs overnight, remember that on 2.0TD you can contract two different power levels: one trimmed for the day and a more generous one for off-peak.

And the lever that isn't up to you

Everything above reduces how much you use. What you pay for each kWh is decided by your contract, and that's usually where the big difference lies. A winter bill is also the best one you can analyse: it's the one that shows your consumption in the worst month of the year, so a comparison based on it doesn't fall short.

At luzgasia you upload your bill — electricity, gas or both, which we analyse separately with their own tax treatment — and we tell you what you'd pay and why. If what you already have is good, we'll tell you that too.

It's free, with no strings attached and no sales calls. Analyse your bill now before the first cold-weather bill lands.