Oil Filled Radiator vs Convection Heater: Which Should You Stock?

A distributor in the UK asked me last month why his oil-filled radiator sales were flat while his convection panels were moving. Both were 2000W. Both had CE certs. Same retail price. The difference wasn't the heater. It was the room.

That's the thing about this category. Buyers don't buy watts. They buy a heating experience. If you're sourcing for a retail program, you need to know which experience your customer actually wants.

How they actually work

A convection heater pulls cold air in at the bottom, runs it past a heating element, and pushes warm air out the top. It heats the air in the room. Fast. Turn it on, you feel it in a few minutes. Turn it off, the warmth goes with it.

An oil-filled radiator heats the oil inside sealed fins. The metal gets hot. The air around the metal gets hot. It's slower to start, maybe 15 to 20 minutes before you feel real heat. But when you turn it off, the oil stays warm for a while. It keeps giving off heat.

That's the whole difference. Air vs mass.

What that means for the buyer

If your customer wants a room warm now, convection wins. If they want a room that stays warm, oil wins.

But here's what most spec sheets don't tell you. Oil-filled radiators are silent. No fan, no click, nothing. That's why they sell to people who need a silent electric heater for a bedroom or a home office. Convection heaters with a fan are not silent. Even the good ones have a hum.

Convection heaters dry the air more. Not because they burn oxygen, that's a myth, but because moving air feels drier. Oil radiators don't move air. Some buyers care about that. Most don't, until they do.

The real numbers

A 2000W heater is a 2000W heater. Running cost is the same at the meter. If your customer runs it 8 hours a day at, say, 0.30 per kWh, that's 4.80 a day. Same for both. The difference is how long they run it. An oil radiator holds heat, so they might run it 6 hours instead of 8. That's a 20% difference in running cost, not because the heater is more efficient, but because the user behaves differently.

Don't let anyone tell you oil-filled is more energy efficient. It isn't. It's just slower to cool down.

For a large room, neither one is great on its own. A 2000W convection heater will heat a 20 square meter room if it's insulated. An oil radiator will do the same room but take longer to get there. If the room is bigger, you need more watts or more units. That's it.

Where each one wins

Convection:

• Bathrooms, if IP24 rated. Fast heat, and people don't stay long.
• Workshops and garages where you need heat while you're working, not after.
• Any space where the user wants a thermostat to kick in and out quickly.

Oil-filled:

• Bedrooms. Silent, steady heat. No fan noise.
• Living rooms where people sit for hours.
• Anywhere the power might go off for a short time. The oil keeps giving heat.

Infrared is a different animal. It heats objects, not air. Good for spot heating, bad for whole-room. Don't mix it into this comparison.

What to stock

If you're a distributor, don't pick one. Stock both. The buyer who wants a wall mounted electric heater for a hallway is not the same buyer who wants a portable oil radiator for a bedroom. You'll lose sales if you force one category.

For private label, the MOQ is usually 200 pcs per model. Lead time is 15 to 45 days depending on whether you need custom packaging or just a logo. CE, RoHS, UKCA, and ERP are standard. If a factory can't show you those four, walk away.

One more thing. Check the thermostat. A cheap mechanical thermostat will swing 3 to 4 degrees. A digital one holds within 1 degree. That's the difference between a 4-star review and a 2-star review. It costs you maybe 2 dollars more per unit. Pay it.

The honest takeaway

Oil-filled radiators and convection heaters are not competitors. They're tools for different jobs. If you're sourcing for a retail program, look at your end customer's room and behavior, not the wattage. The wrong choice sits on the shelf. The right one sells out before January.