Heat pump vs electric radiator: which heats cheaper

Heat pump or electric radiator: which heats more cheaply

An electric radiator converts every kilowatt you pay for into, at most, one kilowatt of heat. A heat pump, by contrast, moves heat from outside to inside and delivers more energy than it consumes. That asymmetry, which sounds like an accounting trick, is the most common answer to the question of the cheapest way to heat with electricity: it is the only technology that provides more heat than the electricity it uses.

The other options usually mentioned in the conversation —oil-filled radiators, air convectors, incandescent bar panels— all belong to the same family: resistances that turn electricity into heat with losses and no multiplier. They do heat, yes. But every watt consumed is a watt paid for.

What a heat pump is and why it costs less to run

The principle is that of a lighter: the gas that escapes cools down, the gas that is compressed heats up. A heat pump applies that cycle to extract energy from the outside air —even when it is cold— and bring it into the home. The key indicator is the COP (coefficient of performance): for every unit of electricity consumed, the unit delivers several units of heat. The higher, the better.

That is why the most repeated advice is to look for units with a high COP, already available on the market, and not to focus so much on the brand. Inverter models, moreover, modulate their output instead of switching on and off, which improves performance and allows the same device to be used as air conditioning in summer. A domestic air conditioning unit, in fact, usually includes a heat pump.

The problem of extreme cold and units that are not what they claim

The catch appears when the thermometer drops. Some warn that, in cold regions, with temperatures between 0 and 5 degrees, the outdoor unit freezes and performance plummets; between 5 and 8 degrees the heat output already suffers. The solution lies in units designed for cold climates, with performance charts for different outdoor temperatures.

The other warning is label fraud: not every appliance that claims to heat uses a heat pump. Some portable and air conditioning models only include an electric resistance and a fan —in other words, they are fan heaters in disguise. It is worth checking the technical specifications before paying.

Oil radiators, convectors and bar panels: what each one is for

Oil-filled radiators and convectors heat the air in the room, and are useful for rooms used occasionally or for warming up quickly after a shower. Incandescent bar panels, if aimed at the person, heat with relatively low consumption, but leave the rest of the room cold. None of them multiplies the electricity consumed.

Against them, some argue that a table stove with a skirt and a 150-watt infrared bulb underneath remains the cheapest system of all: localized heat, the family seated around it and a minimal bill. Less comfort, admittedly, and the risk of kicking the bulb if you are not careful.

The firewood alternative and the real cost of installation

For homes with access to firewood, some propose a circuit of water radiators heated by a classic fireplace, with a small electric pump that moves the water, reducing costs to the electricity for the motor and the fuel. The installation would cost around 5,000 euros and the subsequent cost would be lower than heating oil. With your own firewood, the calculation changes completely.

The full breakdown of that installation, item by item, shows a difference that surprises those who only look at the monthly bill.

And if the price of electricity keeps rising, how many winters can a resistance radiator last before the heat pump pays for itself?