Quick answer
A ceramic heater passes electricity through a ceramic element that heats up in seconds. A fan blows air across it and into the room. Because the ceramic's resistance rises as it gets hotter, it naturally limits its own temperature, so there's no glowing red-hot wire.
How the K1 heats your room, in 4 steps
- Step 1
Plug in and switch on
Use the button or remote and pick your temperature.
- Step 2
Ceramic warms in about 2 seconds
The PTC element heats up fast, then limits its own temperature.
- Step 3
The fan spreads the warmth
A quiet fan blows air across the warm ceramic and into the room.
- Step 4
The thermostat holds it there
Once the room is warm, it switches on and off to save energy.
PTC ceramic, explained
PTC stands for "positive temperature coefficient". It describes a material whose electrical resistance goes up as it gets hotter.
When you switch the K1 on, current flows through the cool ceramic element easily, so it heats up within about 2 seconds. As it warms, its resistance rises and it draws less power. It settles at a safe working temperature on its own. Think of it as a heater with a built-in brake.
That's very different from an old coil fan heater or bar fire, where a metal wire glows red-hot and keeps getting hotter if air can't reach it.
How the warmth spreads around the room
A quiet fan pushes air across the warm ceramic and out into the room. Moving air warms a room much faster than a radiator, which relies on warm air slowly rising. That's why you feel the K1 within seconds rather than minutes.
The thermostat: why typical cost is half of full power
At full power the K1 draws 1200W, about 32p an hour at today's UK price cap. But it doesn't run flat out all evening. Once the room reaches your chosen temperature, the thermostat switches the heater off, then back on when the room cools a little.
In a typical room that means it's at full power roughly half the time, so the average cost is about 16p an hour. In a cold, draughty room it will run more; in a small, well-insulated room, less.
Ceramic vs coil, oil-filled and halogen heaters
- Ceramic (PTC): heats in seconds, self-limiting element, light and portable. A gentle fan sound.
- Coil fan heater: also fast, but a bare wire gets very hot. Can smell of burnt dust and is often noisier.
- Oil-filled radiator: heats oil sealed inside fins. Silent and gentle, but takes 20–30 minutes and is heavy.
- Halogen: a bright bulb warms whatever it points at, not the room. The glow can be tiring and the surface gets hot.
The truth about "energy-saving" heaters
Every electric heater turns almost 100% of the electricity it uses into heat. No heater is "more efficient" in the sense some adverts claim. The money you save comes from three things:
- Heating only the room you're in, instead of the whole house
- Warming up fast, so you run it for less time
- A thermostat that cuts power once you're warm
Be wary of heaters claiming to cost "1p an hour" or to cut your bills by huge percentages. We show exactly how we work out our figures.
The K1's built-in safety
- Tip-over switch. Cuts power if the heater is knocked over.
- Overheat protection. Switches off if the vents are blocked.
- Self-limiting PTC element. No red-hot wire.
- Cool-touch casing. Designed to stay safe to touch.
- No fuel, no fumes. Nothing burns, so there's no carbon monoxide.
What it costs to run (current UK prices)
At the Ofgem price cap of 26.32p per kWh (1 October to 31 December 2026), a 1200W heater like the K1 costs about 32p an hour at full power. Once the room is warm the thermostat switches the heater on and off, so in normal use it averages about 16p an hour.
| How long | Typical cost per day | Over 30 days |
|---|---|---|
| 1 hour | 16p | £4.74 |
| An evening (4 hours) | 63p | £18.95 |
| A working day (8 hours) | £1.26 | £37.90 |
Your own price may be a little higher or lower depending on your region and tariff. See how we calculate running costs or try the running cost calculator with your own unit rate.
How the K1 compares with other heaters
| Heater type | Warm in | Running cost | Safety and comfort |
|---|---|---|---|
| Ofenwerk K1 (ceramic) | About 2 seconds | About 16p/hour typical | Tip-over and overheat cut-off, cool-touch case, no glowing coil |
| Coil fan heater (2–3kW) | Seconds | 53–79p/hour at full power | Hot coil, can smell of burnt dust, often noisy |
| Oil-filled radiator (1.5–2.5kW) | 20–30 minutes | 39–66p/hour at full power | Surfaces get hot, heavy to move |
| Convector (2kW) | 10–15 minutes | About 53p/hour at full power | Heat rises to the ceiling first |
| Electric blanket (100W) | 10–20 minutes | About 3p/hour | Warms the bed only, not the room |
Full-power costs worked out at 26.32p per kWh. Thermostats lower all of these in real use.
Using any electric heater safely
These tips follow UK fire-service and Electrical Safety First advice and apply to any portable heater, including ours:
- Plug the heater straight into a wall socket. Don't use an extension lead or adaptor; they can overheat.
- Keep it at least 1 metre from curtains, bedding, clothes and furniture.
- Stand it on a flat, hard, stable surface where it can't be knocked over.
- Never cover it or dry clothes on it.
- Switch it off at the wall when you go out.
- Check the plug and cable now and then. Stop using it if either is damaged or feels hot.
- Make sure you have a working smoke alarm on every floor. Many UK fire services fit them free for older residents.
Frequently asked questions
What is a ceramic heater?
A ceramic heater warms air by passing it over a ceramic (PTC) element instead of a bare metal coil. The ceramic heats quickly and limits its own temperature.
Are ceramic heaters safe?
PTC ceramic elements limit their own temperature and have no exposed red-hot wire. The K1 adds tip-over and overheat cut-offs. Ceramic heaters do not burn fuel, so they produce no carbon monoxide.
Are ceramic heaters energy efficient?
All electric heaters turn almost 100% of their electricity into heat. A ceramic heater saves money by warming up fast and cutting back once the room is warm, so you heat only the space you're using.
Do ceramic heaters use a lot of electricity?
A 1200W ceramic heater like the K1 uses 1.2 kWh per hour at full power, about 32p at the current UK price cap. With the thermostat cycling, typical use is about 16p an hour.
Can a ceramic heater heat a whole room?
Yes. The fan spreads warm air around the room. A 1200W heater suits rooms up to about 20 m² with reasonable insulation.
Are ceramic heaters better than oil-filled radiators?
They're faster and lighter. Oil-filled radiators take 20–30 minutes to warm up but give gentle, silent heat for long periods. For quick warmth in one room, ceramic usually wins.
How long do ceramic heaters last?
A well-made ceramic heater normally lasts several winters. Keep the vents free of dust. The K1 has a 24-month warranty.
Do ceramic heaters give off carbon monoxide?
No. They're electric and burn no fuel, so they produce no carbon monoxide or fumes.
Do ceramic heaters dry the air?
They don't remove moisture, but warm air can feel drier. A glass of water nearby or a small humidifier helps if you notice it.
Why does a new heater smell at first?
A faint smell for the first few minutes of use is normal for a new heater as manufacturing residue burns off. It should go quickly. If it continues, switch off and contact us.
Sources and how we checked this guide
- Electricity price: Ofgem: energy price cap unit rates and standing charges, checked 25 October 2026.
- Heater safety: UK fire and rescue service advice and Electrical Safety First guidance on portable heaters.
- K1 figures (1200W, about 2-second warm-up, room size up to 20 m², safety cut-offs) come from the product specification.
- Costs are worked out with the method on how we calculate running costs.