Oil-Filled Radiator vs Convection Heater: Which to Source?

A distributor asked me last month why his oil-filled radiator SKU was outselling his convection panels in Canada, but the opposite happened in Germany. Same factory, same 2000W rating, same CE cert. The difference wasn't the product. It was how people heat their homes.

So let's talk about the two workhorses in the electric heater category. If you're placing an order for 200 pcs or 20,000 pcs, you need to know which one your market actually wants.

How they actually work

Oil-filled radiators use a sealed diathermic oil reservoir. The element heats the oil, the oil heats the fins, the fins heat the air. It's slow. It's also silent, because there's no fan. And it keeps radiating heat for 15-20 minutes after you switch it off. That residual warmth is why people in colder climates love them.

Convection heaters pass air over a hot element — either exposed coils or a finned tubular element. Hot air rises out the top, cool air gets pulled in the bottom. Faster warm-up, but the moment you cut power, the heat stops. No thermal mass.

There's a third option: infrared. But that's a different article. For now, stick with these two.

The real-world comparison numbers

Here's what matters for your buyers.

Warm-up time: A 2000W oil-filled radiator takes 10-15 minutes to reach full surface temperature. A 2000W convection panel hits peak output in 2-3 minutes. If your customer wants an electric heater for a bedroom, that speed difference matters for morning routines.

Noise: Oil-filled is dead silent. Convection units with a fan are not. If you're sourcing a silent electric heater for a nursery or office, oil-filled wins. Fan-assisted convection models sit in the middle — you can hear them, but it's white noise.

Running cost: Both draw the same wattage at full tilt. But oil-filled units cycle on and off more because of that thermal mass. In a well-insulated room, an oil-filled radiator can use 10-15% less energy over an 8-hour period to hold the same temperature. That's the kind of number that sells on Amazon. "Energy efficient electric heater" is a search phrase that converts, and oil-filled has the data to back it up.

Weight and shipping: A 2000W oil-filled radiator weighs 12-15 kg. A comparable convection panel weighs 3-5 kg. That's a big deal for ocean freight and for Amazon FBA fees. If your buyer is price-sensitive on landed cost, convection wins.

Wall-mount vs portable: Convection panels are natural wall-mounted electric heaters. Oil-filled radiators are almost always portable, with casters. If your market rents apartments and moves often, portable oil-filled sells. If they own homes and want permanent installs, wall-mounted convection is the SKU.

What buyers actually ask

A procurement manager for a European retail chain told me last year: "We need a low wattage electric heater for bathrooms." That's a specific ask. Bathrooms need IP24 at minimum. Oil-filled radiators are rarely IP-rated because of the oil and the metal casing. Convection panels can be built to IP24, and we do it regularly. MOQ 200 pcs, lead time 25-30 days, CE and UKCA on the label.

For garages and workshops, it flips. People want fast heat, and they don't care about silence. A 3000W industrial fan heater or a high-output convection unit is the right call. Oil-filled takes too long to warm a cold slab.

For a large room or open-plan office, convection wins on airflow. Oil-filled radiators heat locally. They don't move air. If you need to push heat across 40 square meters, you need a fan or a tall convection panel.

The thermostat question

Both types can carry a mechanical or digital thermostat. The difference is accuracy. A cheap mechanical thermostat on an oil-filled radiator can swing 3-4°C. A digital thermostat with a remote sensor holds ±1°C. If you're selling a best electric heater with thermostat, spend the extra $2-3 on the BOM for a digital control. Returns drop. Reviews go up.

WiFi is the other lever. A wifi smart electric heater adds $4-6 to the unit cost. For Amazon buyers, it's often the difference between page 1 and page 3. For private label electric heater brands, it's table stakes in 2025.

One honest takeaway

Don't source both types for the same market unless you have data showing demand for both. Pick one based on how your customers heat their homes: oil-filled for silent, steady, portable heat in colder climates. Convection for fast, lightweight, wall-mounted heat in milder or space-constrained markets. If you're wrong, you'll sit on 500 pcs of the wrong SKU for 18 months. I've seen it happen. It's not fun.