If you work from home, or spend most of your evening in one room, heating an entire house to keep one person warm is an expensive way to solve a small problem. The obvious answer is to heat just that room. The question everyone asks next is: what will that actually cost me?
Here is the honest arithmetic, with no marketing nonsense.
The only formula you need
Every electric heater in Britain is essentially 100% efficient — all the electricity it draws becomes heat. That's true of a £15 heater and a £300 one. So running cost depends only on wattage and your unit rate:
Cost per hour = (watts ÷ 1000) × your electricity unit rate in pence
Your unit rate is printed on your bill or in your energy app, in pence per kWh. It varies by tariff and region, and it changes when the price cap is reviewed — so check your own bill rather than trusting any figure you read online, including this one. The examples below use 25p per kWh purely for illustration.
What that means in practice
| Appliance | Typical power | Cost per hour at 25p/kWh |
|---|---|---|
| Electric foot warmer / heated pad | ~60 W | ~1.5p |
| Heated throw or blanket | ~100 W | ~2.5p |
| Small desk fan heater (low) | ~1,000 W | ~25p |
| Small fan heater (high) | ~2,000 W | ~50p |
| Oil-filled radiator | ~1,500 W | ~38p |
| Gas central heating (whole house) | — | Varies hugely by home |
The pattern is stark, and it is the single most useful thing to understand about home heating:
Heating a person is roughly ten to twenty times cheaper than heating a room.
A 60 W foot warmer under your desk costs somewhere around a penny and a half an hour. A 2 kW fan heater warming the same room costs roughly thirty times that. Both make you feel warmer. Only one of them shows up on your bill.
The order to do things in
1. Warm yourself first
Cold hands and cold feet are what actually make you feel cold. Fix those and the room can be a couple of degrees cooler without you noticing.
If you're sitting at a desk, your feet are the priority — they're furthest from your core, least active, and usually resting on a cold floor. An under-desk foot warmer draws around the same power as a light bulb and targets exactly the spot that makes you reach for the thermostat. Heated throws work on the same principle for evenings on the sofa.
2. Then heat the small space around you
If you do need to warm the air, warm a small volume of it. A compact heater in a home office with the door shut is doing a fraction of the work of central heating running through empty rooms.
For a desk or a small bathroom, a compact desk heater is enough — it warms the space immediately around you rather than the whole room. For an actual room, a 1200W ceramic heater reaches full output in seconds, so short bursts genuinely work.
The key habit is heat the space you're in, when you're in it, then turn it off. Small heaters are for bursts, not background running — leave a 2 kW heater on all day and it will comfortably out-cost your central heating.
3. Stop the heat you have from leaving
Free or nearly free, and permanent:
- Draught-proof the door to the room you're heating. A rolled towel at the base works today; a proper draught excluder works better.
- Close the curtains at dusk — windows are the biggest heat loss in most rooms.
- Don't block radiators with sofas or drying laundry.
- Close doors to rooms you aren't using and turn those radiators down.
- Reflective panels behind radiators on external walls, if you're in an older property.
The trap: heating one room badly
There is a real catch, and it's worth being straight about it.
If you heat one room hard and let the rest of the house go cold, you are creating exactly the conditions for condensation and mould — warm moist air moving into cold rooms and dumping its moisture on cold walls and windows.
So don't let unused rooms drop to freezing. Keeping the rest of the home at a low background temperature, ventilating in short bursts, and heating your one room on top of that is the balance that keeps both your bills and your walls in reasonable shape. We wrote a full guide on this: how to stop condensation on windows.
If bills are genuinely a problem
Cheap kit helps at the margins, but it isn't a substitute for support that exists precisely for this. If you are struggling to afford heating, look into the Warm Home Discount, Winter Fuel Payment eligibility, and your supplier's hardship fund — all suppliers are required to offer support and many have grants that go unclaimed. Citizens Advice offers free, independent guidance on all of it.
There's no sense in us selling you a £30 gadget if you're entitled to a few hundred pounds you haven't claimed.
The short version
- Work out your real cost per hour: (watts ÷ 1000) × your unit rate.
- Heating your body beats heating the air, by a factor of ten or more.
- Use small heaters in short bursts, in small closed spaces.
- Draught-proof and close curtains — free, and permanent.
- Don't let the rest of the house go cold and damp to save a few pence.
NovaDrop stocks compact heating and comfort kit for small UK homes and home offices, dispatched from our UK warehouse in 2–5 working days. Free UK delivery on orders over £50.