Oil-Filled Radiator vs Convection Heater: Factory Comparison

A buyer asked me last week: "Why would I stock oil-filled radiators when convection panels are cheaper and lighter?" Fair question. I've watched both lines run for 15 years. Here's the honest breakdown.

How they actually heat

A convection heater pulls cold air in the bottom, runs it over a hot element, pushes warm air out the top. Fast. You feel heat in 30 seconds. But when the thermostat clicks off, the warmth stops. The room cools almost as quickly as it heated.

An oil-filled radiator works differently. The element heats diathermic oil inside sealed fins. Those fins stay warm for 20 to 30 minutes after power cuts. That's the whole point. It's radiant and convective heat combined, slower to start but steadier.

If your customer wants a blast of heat while they're standing in front of it, convection wins. If they want a room that stays comfortable without the heater cycling every two minutes, oil-filled wins.

The numbers that matter for sourcing

Standard oil-filled radiator: 1500W or 2000W, 7 to 11 fins. A 2000W unit takes about 20 minutes to reach full surface temperature. A 2000W convection panel takes 2 minutes.

But here's the catch. Convection panels lose heat fast. Oil-filled units hold it. For an electric heater for bedroom use, that stored heat matters. Nobody wants a heater that clicks on and off all night. The oil-filled radiator runs quieter and more evenly. That's why it's often the better pick for a silent electric heater request — no fan, no expansion noise, just gentle radiant warmth.

Convection panels are cheaper to make. Fewer parts, less steel, no oil. Our cost difference at the factory is roughly 18 to 22 percent. That shows up in your landed cost. If you're sourcing for a price-sensitive market, convection panels move faster.

Wall-mounted vs portable

Most of our oil-filled radiators ship with castors and handles. Portable. The buyer plugs it in, rolls it where they need it. Simple.

Wall-mounted convection panels are fixed. They save floor space. For a wall mounted electric heater in a hallway or bathroom, convection is usually the right call because it's slim and can be IP24 rated. Oil-filled radiators are rarely IP-rated. Water and oil don't mix, and sealing a finned radiator to IP24 is expensive and unnecessary.

If a buyer asks for an electric heater for bathroom IP24, don't push oil-filled. Push a convection panel with the right gasket and IP rating. That's the honest answer.

Running cost and efficiency

Both types are 100 percent efficient at the point of use. Every watt of electricity becomes heat. The difference is how that heat is delivered and how long it stays in the room.

A 2000W oil-filled radiator running 8 hours a day at full draw uses 16 kWh. Same as a 2000W convection panel. But in practice, the oil-filled unit cycles less because the oil holds temperature. In a well-insulated room, that can mean 10 to 15 percent less runtime. Not a miracle, but real.

For a cheap to run electric heater, the real answer is a lower wattage unit with a good thermostat. A 1000W oil-filled radiator in a small office will cost less to run than a 2000W convection panel that's oversized for the space. Buyers who ask about electric heater running cost usually need education, not a bigger element.

Thermostats and controls

Basic mechanical thermostat: cheap, reliable, ±3°C accuracy. Good enough for a garage or workshop.

Digital thermostat with timer: ±1°C, more features, higher return rate if the UI is confusing. We see more warranty claims on digital units, mostly user error.

WiFi smart control: popular with Amazon buyers. Adds $4 to $7 to unit cost. The wifi smart electric heater category is growing, but returns are higher because of app pairing issues. If you're a private-label brand, make sure your app is solid before you commit to a container.

What I'd stock

If you're a distributor selling to hardware stores, stock both. Convection panels for bathrooms, hallways, and quick heat. Oil-filled radiators for bedrooms, offices, and anywhere people sit still for hours.

If you're an Amazon seller, start with a 1500W oil-filled radiator with a mechanical thermostat and castors. It's the safest bet. Low return rate, easy to ship, and it fits the electric heater for large room search without overpromising.

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

The honest takeaway

Oil-filled radiators and convection heaters solve different problems. One stores heat, the other moves air. Don't let a supplier tell you one is universally better. Match the product to the use case, check the certs, and run the numbers on your own landed cost. The rest is just marketing.