Oil-Filled Radiator vs Convection Heater: An OEM Guide for Buyers

I've watched container loads of both leave our floor since 2009. Buyers ask me the same thing every fall: which one should I stock? The honest answer depends on where your customer will plug it in. Both are electric resistance heaters, so both convert every watt to heat. The difference is how they deliver it, and that changes the room, the noise, and the returns rate.

How each one actually works

A convection heater pulls cold air in at the bottom, runs it across a finned element, and pushes warm air out the top. It heats the air in the room fast. Turn it off and the room cools almost as fast. That's the trade-off.

An oil-filled radiator heats a sealed body of thermal oil inside steel columns. The element never touches the air. The oil warms, the metal warms, and the unit keeps radiating after the power cuts. It's slower to start, but it holds temperature longer and stays silent because there's no fan.

Where each one wins

Convection units are the workhorse for bathrooms, small offices, and anywhere you need heat in five minutes. A 2000W panel will warm a 15m² room quickly. If you're sourcing an electric heater for office use or a rental unit where tenants want instant warmth, convection is the easy sell.

Radiators are the better fit for bedrooms, nurseries, and living rooms where people sit for hours. No fan noise, no dust blowing around, and the surface stays warm after shutdown. If your customer is looking for a silent electric heater, this is the category. They're also the safer pick around kids and pets because the element is enclosed.

The numbers that matter

Both draw the same power. A 2000W unit on high for one hour uses 2 kWh. At £0.30/kWh in the UK, that's £0.60 an hour. Running cost is identical at the same wattage. The radiator just cycles on and off less once the room is at temperature, so real-world consumption can be 10–15% lower over a long evening. That's the only honest efficiency gap.

For large rooms, don't oversell a single 2000W unit. A 30m² space needs two units or a higher-output industrial fan heater. Buyers who promise one radiator will heat a whole open-plan floor get returns. I've seen it.

What to spec for each market

For the EU and UK, ERP Lot 20 is non-negotiable. That means a programmable thermostat, open-window detection, and adaptive start on most models. CE and RoHS are baseline. UKCA is now required for Great Britain. For bathrooms, IP24 is the minimum, and you can't sell a radiator with a metal case into that environment unless it's specifically rated.

MOQ is 200 pcs per model. Lead time runs 15–45 days depending on whether you need custom tooling, private label packaging, or a new control board. If you're a private label electric heater brand, budget 30 days for the first run and 15–20 for repeats.

Thermostats and smart features

Mechanical thermostats are cheap and reliable. Digital ones cost a few dollars more and cut returns because the temperature is predictable. WiFi smart electric heater models add $6–12 to the BOM and open the door to app control, scheduling, and energy monitoring. That's a real selling point for Amazon buyers, but it also means you need firmware support and a cloud backend. Don't add WiFi unless you can support it for five years.

What I'd stock

If you're a distributor with limited shelf space, carry one 1500W and one 2000W convection panel, and one 2000W oil-filled radiator with 9–11 fins. That covers most of the market. Add a 500W low wattage electric heater for small rooms and RVs if you have the SKU budget. Skip the 3000W+ residential units unless you're selling into workshops or garages, where an industrial fan heater is the right tool anyway.

One last thing: don't chase the cheapest BOM. The element and the thermostat are where failures happen. A $1 saving on a thermostat costs you a container of returns. Pay for the good switch.

The honest takeaway

There's no universal winner. Convection for fast heat and small spaces. Oil-filled for silent, steady warmth and longer sessions. If you stock both and explain the difference clearly on the box, you'll get fewer returns and better reviews than any single-model bet.