Oil Filled Radiator vs Convection Heater: What to Source

If you're sourcing heaters for a European winter, the first question you'll get from a buyer isn't about wattage. It's about whether to stock oil-filled radiators or wall-mounted convection panels. Both sell. Both have loyal repeat customers. But they are not interchangeable, and if you pick wrong for your market, you'll eat the returns.

I've watched this play out for 15 years on the factory floor. Let me break down what actually matters when you're deciding what to put in your container.

The core difference is heat transfer, not just shape

An oil-filled radiator heats oil inside a sealed metal fin. That oil holds heat and radiates it slowly into the room. A convection heater pulls cold air in at the bottom, passes it over a heating element, and pushes warm air out the top. That's it. One radiates, one convects.

That difference drives everything else: warm-up time, room feel, energy bills, and even where the unit can be mounted.

Oil-filled radiators are slow. A typical 1500W unit takes 20 to 30 minutes to feel warm on the skin. But once it's hot, it keeps throwing heat for another 20 to 30 minutes after the thermostat cuts power. That thermal mass is why they feel steady. No sudden cold drafts. No hot blast then dead air.

Convection panels, on the other hand, are fast. A 2000W wall-mounted panel will push warm air within three to five minutes. But the moment you turn it off, the heat stops. No stored energy. The room cools quickly. That makes them better for spaces you use intermittently, like an office or a workshop, and worse for a bedroom you want warm when you wake up.

Real numbers on running cost and feel

Let's talk about running cost, because that's what your customers actually search for. They type "cheap to run electric heater" into Amazon and expect a straight answer. Here's a straight one: for the same wattage and same thermostat setting, an oil-filled radiator and a convection heater will use nearly identical electricity. Electric resistance heating is roughly 100% efficient regardless of type. The difference is in how long each runs.

An oil-filled radiator holds heat, so it cycles on and off less frequently in a well-insulated room. In a 20 square meter bedroom with average insulation, a 1500W oil-filled unit might run 40% of the time over eight hours. That's about 4.8 kWh. A 1500W convection heater in the same room might run 55% of the time because the room cools faster between cycles. That's 6.6 kWh. Over a month, that's roughly 50 kWh extra. At €0.25 per kWh, that's €12.50 more per month for convection.

But that advantage flips in a drafty garage or a room you only heat for 30 minutes. In that scenario, convection heats the air faster, so you use it for less time total. There's no universal winner. That's why you should stock both if you can.

What your customers actually ask about

Buyers often ask me: "oil filled radiator vs convection heater, which is better for a bedroom?" My answer is always the same. For a bedroom where someone sleeps eight hours, oil-filled wins. It's silent (no fan), it doesn't dry the air as aggressively, and the heat is more even. It's also safer to leave on overnight because the surface temperature is lower than a convection element.

For a living room or office where people come and go, convection wins. It's lighter, mounts on the wall, and doesn't take up floor space. That's why "wall mounted electric heater" is such a common search term. People want to reclaim floor area.

Another frequent question is about bathroom use. If you're sourcing for bathrooms, you need IP24 rating. That means the unit is protected against splashing water from any direction. We make both oil-filled and convection units with IP24, but convection panels are more common in bathrooms because they're thinner and can be mounted higher on the wall, away from splash zones.

Build quality and safety differences you must check

Here's where I get blunt. Not all heaters are built equal, and the difference is in the safety internals, not the cosmetic shell.

For oil-filled radiators, check the weld quality on the fins. A weak weld will leak oil after a few hundred thermal cycles. That's a fire hazard and a warranty nightmare. We pressure-test every unit at 2.0 MPa before it leaves the factory. Ask your supplier if they do that. If they don't, walk away.

For convection heaters, the critical part is the thermal cutoff. It needs to trip reliably at 90°C, not 120°C. A cheap bimetal strip can fail after 10,000 cycles. We use a manual reset thermal fuse on all our convection panels. That means if it overheats, it shuts off permanently and has to be manually reset. It costs us 20 cents more per unit. It saves you from a recall.

Also check the tip-over switch. For any portable heater, that's a mandatory safety feature in most markets. But for wall-mounted units, you need a different protection: a tilt sensor that cuts power if the unit is knocked off its brackets. I've seen cheap imports skip that. Don't be one of them.

Sourcing practicalities: MOQ and lead time

If you're a private label buyer, you're probably wondering about minimums. Our standard MOQ is 200 pieces per model, but we can mix colors or cord lengths within that. Lead time is 15 days for a standard convection panel, 25 days for an oil-filled radiator (because the oil filling and leak testing take time), and up to 45 days if you want custom tooling or a new PCB.

For CE, RoHS, and UKCA, we have them all. ERP (energy-related products) compliance is also done for the EU. Don't assume every Chinese factory has these. Many only have a CE sticker, not a real CE certificate. Ask for the test report from a third-party lab like TÜV or SGS. If they can't produce it, move on.

The honest takeaway

Here's the truth: there is no "best" electric heater. There's only the right heater for a specific room and a specific use pattern. If you're sourcing for a broad retail market, you need both types. Oil-filled radiators will be your bread and butter for bedrooms and quiet spaces. Convection panels will be your fast movers for offices, bathrooms, and anyone who wants a wall-mounted unit.

If you're a smaller buyer and can only pick one, start with oil-filled. They have fewer returns because people understand them. They're also easier to ship without damage than thin convection panels that can bend in transit. But don't ignore the convection trend. In the last two years, our convection panel orders have grown 30% year over year, mostly from Amazon sellers who want a lighter, cheaper-to-ship product.

Make your decision based on your market's climate and room types. And when you talk to any factory, ask the hard questions about welds, thermal cutoffs, and real test reports. That's how you avoid a container full of problems.