Oil Filled Radiator vs Convection Heater: Factory Comparison

A distributor in Hamburg asked me last month why his oil-filled radiator returns were double his convection panel returns. Same wattage, same room size. The difference isn't the product. It's how buyers use them.

I've run production lines for both since 2009. Here's what actually separates them, and when you should stock one over the other.

How they heat (and why it matters for returns)

Convection panels heat air. Ours pull 1000W or 2000W, the element warms the fins, air rises off the top, cool air pulls in from the bottom. You feel warmth in 3 to 5 minutes. Turn it off, the room cools in 15.

Oil-filled radiators heat mass. Inside is diathermic oil, the element heats the oil, the oil heats the steel fins. That takes 15 to 20 minutes to feel. But once it's hot, it keeps radiating for 20 to 30 minutes after you cut power. That's the trade-off.

If your customer wants fast heat in a bathroom or a home office they pop in and out of, a convection panel wins. If they want steady background heat in a bedroom overnight, oil-filled is the better sell. I've seen return rates drop 40% just by putting that sentence on the retail box.

The real numbers buyers ask about

Running cost is the question every procurement manager asks. At 1500W on full blast, both draw 1.5 kWh per hour. At £0.30/kWh, that's £0.45 an hour. No difference at the wall.

The difference is duty cycle. A convection heater in a well-insulated 20m² room might cycle 40% of the time once at temperature. An oil-filled unit in the same room cycles closer to 25% because the oil holds heat. That's where the "cheap to run electric heater" claim comes from. It's real, but it depends on insulation and thermostat quality, not the heater type alone.

We ship both with CE, RoHS, UKCA, and ERP-compliant thermostats. The ERP lot 20 rules killed the old dumb bimetal thermostats. If a supplier quotes you a heater without electronic thermostat control, they're either lying or sitting on old stock.

Wall mounted vs portable

Wall-mounted electric heaters are almost always convection. You can't mount a 10kg oil-filled radiator on a plasterboard wall without serious anchors, and most retail buyers won't try. So if your channel is rental apartments, student housing, or anywhere floor space is tight, stock wall panels.

Oil-filled radiators are portable by design. Castors, carry handles, 2 to 3kW. They sell to homeowners with cold spare bedrooms, conservatories, and garages. A 2000W oil-filled unit in a single garage will hold 12 to 15°C above ambient in winter. A 2000W wall panel in the same garage fights the concrete slab and loses.

For a garage, workshop, or basement, neither is ideal. That's fan heater territory. But if a buyer insists on silent operation, oil-filled is the only one that makes zero noise. No fan, no clicking relay if you spec a triac controller.

Infrared vs convection, briefly

Infrared heats objects, not air. It's instant, directional, and useless behind a sofa. We build infrared panels too, and they sell well for bathrooms and outdoor patios. But for a large room, convection or oil-filled still moves more total heat. Don't let a buyer talk you into stocking infrared as a primary room heater. It's a supplement.

What to stock, and what to spec

If you're a private-label brand doing Amazon, the safe mix is:

• 2000W wall-mounted convection panel with wifi smart electric heater control. MOQ 200 pcs. 15 to 25 days lead time.
• 2000W oil-filled radiator with 11 fins, mechanical or electronic thermostat. MOQ 200 pcs. 20 to 30 days.
• 1500W infrared panel for bathroom IP24. MOQ 300 pcs because of the glass tooling.

For OEM electric heater manufacturer China orders, the cert package adds 5 to 7 days. CE and RoHS are standard. UKCA if you ship to Britain. ERP is non-negotiable for the EU.

One spec note: if you're selling into Germany or Scandinavia, insist on a frost-watch function. It's a 5W standby mode that kicks in below 5°C. Costs us about $0.80 per unit to add. Cuts winter complaint tickets by half.

The honest takeaway

Oil-filled radiators and convection heaters are not competitors. They're two tools for two different jobs. If you stock only one, you'll lose sales to whichever competitor stocks the other. The buyers who get burned are the ones who order 500 oil-filled units for a summer promotion, then eat the storage cost until October.

Match the heater to the room and the season. That's the whole game.