Oil Filled Radiator vs Convection Heater: Buyer's Guide

If you're sourcing electric heaters for a European or North American distributor, you'll eventually face this question: oil filled radiator vs convection heater. Both are staples in the category, but they serve different buyers and different rooms. I've watched container after container go out the door since 2009, and the answer isn't as simple as "oil is better" or "convection is cheaper."

How They Actually Work

A convection heater pulls cold air in at the bottom, passes it over a metal finned element, and pushes warm air out the top. It's simple. Heat starts within seconds. The downside is that when the thermostat clicks off, the warmth stops almost immediately. You feel a slight chill before it kicks back on.

An oil filled radiator heats a sealed diathermic oil inside steel columns. The oil warms the metal surface, which then radiates and convects heat into the room. It takes 10 to 15 minutes to reach full output, but once there, it keeps releasing heat for a while after the power cuts. That thermal mass is why people call them a silent electric heater. No fan, no click, no dry air movement.

Where Each One Wins

Convection units are cheaper to make. A 2000W wall mounted electric heater or freestanding panel can retail for under €40 in volume. They're light, easy to ship, and work well in bathrooms with IP24 rating, offices, and small bedrooms where you want fast heat on demand.

Oil filled radiators cost more. The steel, the oil, the welding, and the pressure testing add up. But they hold heat longer, run silently, and don't dry out the air as aggressively. For a bedroom or a large room where you want steady background warmth, they're often the better pick. Buyers searching for an energy efficient electric heater usually lean toward oil filled because the thermostat cycles less often once the room is at temperature.

The Real Numbers Buyers Ask About

Running cost is the first thing procurement managers calculate. A 1500W oil filled radiator on a 25°C thermostat in a 20m² room might cycle 40% of the time. That's roughly 0.6 kWh per hour. A 2000W convection heater in the same room cycles more frequently, maybe 50% duty cycle, so 1.0 kWh per hour. Over a 4-hour evening, that's 2.4 kWh vs 4.0 kWh. At €0.25 per kWh, you're looking at €0.60 vs €1.00. Not huge, but distributors use that math in their marketing.

Low wattage electric heater models (500W to 800W) are a separate niche. They're popular for bathrooms, RVs, and small offices where the circuit can't handle 2000W. A 12v electric heater for RV campervan is a different beast entirely, usually a 300W to 500W PTC element running off an inverter. Don't confuse it with household units.

Certifications and Compliance

For Europe, you need CE and RoHS. UKCA for the UK market. ERP Lot 20 applies to local space heaters, so your thermostat and standby power consumption must meet the limits. Most of our oil filled radiators ship with a 7-day programmable timer and open-window detection to comply. Convection panels can meet ERP with a simpler mechanical thermostat, but the standby limit is stricter.

For North America, UL or ETL is the norm. We build to both. MOQ is typically 200 pcs per model, mixed containers are fine. Lead time runs 15 to 45 days depending on whether you need custom packaging, private label electric heater branding, or a custom plug.

What I'd Tell a First-Time Buyer

If you're sourcing for Amazon, start with a 1500W oil filled radiator with a digital thermostat and a 24-hour timer. It's the safest bet for reviews because it's quiet, holds heat, and doesn't have a fan that can fail. Pair it with a 2000W convection panel for the budget tier. That covers most of the market.

If you're sourcing for a retail chain that wants a wall mounted electric heater for bathrooms, go convection with IP24. Oil filled units are too heavy for wall mount in most cases, and the IP rating is harder to achieve with the oil column design.

One Honest Takeaway

The oil filled radiator vs convection heater debate isn't about which is better. It's about which one fits your buyer's room, budget, and tolerance for waiting. Oil filled costs more upfront but runs cheaper and quieter. Convection is cheaper to buy and faster to heat but cycles more and can feel drafty. If you're not sure, order samples of both. Run them in a 20m² room for a week. The data will tell you more than any spec sheet. And when you talk to a factory, ask for the duty cycle test results, not just the wattage. That's where the real running cost lives.