Oil Filled Radiator vs Convection Heater: Factory Comparison

Most buyers ask 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 heater pulls cold air in the bottom, heats it over a finned element, and pushes it out the top. Simple. Cheap to make. Heats a room fast.

An oil filled radiator seals thermal oil inside metal columns. The element heats the oil, the oil heats the metal, the metal radiates and convects. Slower to warm up. Stays warm after you cut power.

That's the whole difference. Everything else is marketing.

Warm-Up Time and Comfort

Convection wins on speed. A 2000W panel gets a 20 sqm bedroom from 12°C to 20°C in about 15 minutes. The oil filled unit takes 30 to 40 minutes to hit the same temperature.

But here's what buyers miss. Convection heaters cycle on and off hard. You feel the draft. Oil filled radiators hold temperature steadier because the oil mass buffers the cycles. For a bedroom, that matters. For a workshop where you're moving around, it doesn't.

If your customer wants a silent electric heater, both qualify. No fan, no noise. The oil filled unit is slightly quieter because there's no air rush at all.

Running Cost Reality

Both draw the same wattage. A 2000W heater is 2000W whether it's oil or convection. The electric heater running cost is identical at the meter.

The difference is duty cycle. Oil filled radiators stay warm after the thermostat cuts power, so they cycle less often in a well-insulated room. In a leaky garage, that advantage disappears. The heater runs flat out either way.

Don't let anyone tell you oil filled is "energy efficient" in absolute terms. It's not. It's just slower to lose heat. That's a comfort feature, not a savings feature.

Where Each One Wins

Convection panels win for:

• Bathrooms (IP24 rated models, wall mounted, fast heat)
• Offices and small bedrooms where you want quick response
• Wall mounted electric heater applications where floor space is zero

Oil filled radiators win for:

• Bedrooms where steady, silent heat matters
• Rooms with people sitting still for hours
• Markets where customers associate oil filled with "premium"

For an electric heater for large room use, neither is ideal. You need 2000W minimum plus good insulation. A single 2000W unit won't heat 40 sqm in a cold climate. Sell two, or sell a fan heater.

Manufacturing and Sourcing Notes

Both product types share the same core: element, thermostat, thermal cutout, housing. The oil filled unit adds a welded oil column assembly and a pressure test. That's why oil filled costs 15-25% more at factory gate.

Standard MOQ is 200 pcs per model. Lead time runs 15-45 days depending on whether you need custom tooling, private label packaging, or just a logo print.

Certs you'll need: CE and RoHS for EU, UKCA for UK, ERP for energy labeling. Don't skip ERP. Customs will flag it.

For private label electric heater programs, oil filled gives you more surface area for branding. Convection panels are thin. Not much room for a logo.

Thermostat and Smart Features

Both can take the same mechanical thermostat or the same wifi smart electric heater module. We've shipped both. The smart module adds about $4-6 to unit cost at 200 pcs. Worth it for Amazon sellers targeting the "best electric heater with thermostat" search.

One warning: cheap mechanical thermostats drift. After 18 months, a 20°C setting might actually be 23°C. If your market cares about accuracy, spec a digital thermostat. Costs more. Returns less.

The Honest Takeaway

There's no universal winner. Convection is faster and cheaper. Oil filled is steadier and quieter. Pick based on your end customer's room and patience level.

If you're stocking one SKU to test the market, start with a 2000W convection panel. Lower cost, faster sell-through, easier to ship. Add oil filled once you know your buyers.

And whatever you choose, don't promise "cheap to run." At 2000W, both cost the same per hour. The only way to cut running cost is to cut wattage or cut run time. Physics doesn't care about your packaging copy.