Oil Filled Radiator vs Convection Heater: Factory Truth

Every week a buyer asks me the same thing: which one should I stock, oil filled or convection? I've built both on the same line since 2009. Here's the honest breakdown.

How they actually work

A convection panel heats a metal element, air passes over it, hot air rises. Simple. Cheap to make. A 2000W wall mounted electric heater can hit full output in 90 seconds. But when the thermostat clicks off, the heat stops. You feel it.

An oil filled radiator heats the oil inside, then the metal fins radiate. Takes 8 to 12 minutes to warm up. But after you cut power, it keeps throwing heat for another 15 to 20 minutes. That lag matters in a bedroom. People notice it.

I've seen buyers pick convection because the unit cost is lower. Then they get returns because customers say "it doesn't stay warm." That's not a defect. That's physics.

Running cost, real numbers

A 2000W heater on full for one hour uses 2 kWh. At UK rates around 24p per kWh, that's 48p an hour. In Germany, closer to 30 cents. In the US, maybe 15 to 20 cents depending on state.

But here's the catch. A 1500W oil filled radiator often feels warmer than a 2000W convection panel in a large room because the radiant heat doesn't just blow past you. So the cheap to run electric heater isn't always the lower wattage one. It's the one that cycles off sooner and stays warm longer.

For a garage or workshop, convection wins. You want heat now, you're moving around, you don't care about the lag. For a bedroom or office, oil filled. Silent, no fan noise, no dust burn. That's why the silent electric heater tag usually points to oil units.

What buyers get wrong

MOQ. We run 200 pcs standard for either type. But tooling for a custom oil filled radiator body costs more than a convection panel. If you're testing a new market, start with convection. Lower risk. If you're building a private label electric heater line for a premium retailer, oil filled holds margin better.

Lead time. 15 to 45 days depending on whether you need CE, RoHS, UKCA, or ERP compliance testing. ERP is the one that trips people up. The EU ecodesign rules for local space heaters have been tight since 2018. If your supplier says "CE certified" but can't show you the ERP test report, walk away.

Thermostats. A mechanical thermostat on a cheap convection heater has a dead band of 3 to 4°C. That means the room swings. A digital thermostat with a ±0.5°C tolerance costs us about $1.20 more per unit. For a best electric heater with thermostat claim, that's the difference between a 3-star and 5-star review.

Infrared vs convection, quick note

Infrared heats objects, not air. Good for a workshop where you're standing in one spot. Bad for a whole room. If a buyer asks for an infrared heater vs convection comparison, tell them infrared is a spot heater. Don't sell it as a room heater. You'll get returns.

The honest takeaway

There's no universal winner. Convection for fast heat, lower unit cost, and garages. Oil filled for silence, steady warmth, and bedrooms. If you're sourcing from an OEM electric heater manufacturer in China, ask for the ERP report and a 200 pcs trial run before you commit to a container. And don't trust a supplier who promises 10-day lead time on a custom oil filled unit. It's not real.