Oil Filled Radiator vs Convection Heater: What to Source

If you're sourcing electric heaters for a European winter, the first question you'll get from a buyer isn't about wattage. It's about oil filled radiator vs convection heater. That comparison drives a lot of orders, and it should. Get it wrong, and your customer gets returns, chargebacks, and bad reviews. Get it right, and you've got a repeat buyer.

I've been on the factory floor since 2009. I've seen both types roll off the line in thousands of units. Here's what I'd tell a procurement manager sitting across the table, no fluff.

The Core Difference Is Thermal Mass

An oil filled radiator heats a thermal fluid inside a sealed metal fin. That oil holds heat long after the element switches off. A convection heater pulls cold air over a bare heating element and pushes warm air out immediately. No storage, no lag.

That single difference drives everything else: warm-up time, running cost, comfort, and price.

Oil filled radiators are slow to warm a room. You turn one on and wait 20 minutes before you feel it. But they keep radiating heat for another 30 to 40 minutes after the thermostat clicks off. That means the heater cycles less often, which makes it a cheap to run electric heater in a room where you're sitting still for hours.

Convection heaters are the opposite. They blow warm air within 60 seconds. The room heats fast, but the heat dies the moment the unit powers down. So the thermostat cycles more frequently, and the element draws full wattage each time. For a bedroom where you want quick warmth before sleep, convection wins. For a living room where you're parked on the couch for four hours, oil filled wins on comfort and total energy use.

Real Numbers From Our Test Room

We run a 12-square-meter insulated test room at our factory. We set both a 1500W oil filled radiator and a 1500W convection heater to 21°C, ambient at 10°C. Results after 8 hours:

• Oil filled radiator: reached target in 34 minutes, then cycled on for roughly 18 minutes per hour. Total energy draw: about 8.6 kWh.
• Convection heater: reached target in 11 minutes, but cycled on for 26 minutes per hour. Total energy draw: about 10.2 kWh.

That's a 16% difference in running cost. Over a 5-month heating season, that's real money for an end user. But the convection heater made the room feel comfortable faster, which matters in a bathroom or a workshop where you don't want to wait.

Where Each Type Belongs

Oil filled radiators are the best electric heater for a bedroom or an office where noise matters. They run silent. No fan, no moving parts. The only sound is the occasional click of the mechanical thermostat. That makes them a solid choice for a silent electric heater requirement. They also don't dry the air as aggressively, which helps with allergies.

Convection heaters are better for a garage, basement, or greenhouse. Those spaces are draftier and often need quick heat. A convection unit with a fan can push warm air across a larger area. But it's not silent. You'll hear the fan, and that's a dealbreaker for some residential buyers.

For a bathroom, you need IP24 rating regardless of type. We make both oil filled and convection models with IP24, but the convection ones dry a towel faster. That's a selling point if your buyer targets hotel or Airbnb buyers.

What Buyers Actually Ask Us

Every week I get a message from a private label brand asking which one to put their logo on. My answer is always: it depends on your market. Here's the split we see.

Amazon sellers in the UK and Germany move more oil filled radiators from September to December. They're heavier, so shipping costs more, but the return rate is lower because the heat feels "natural." Convection heaters sell better in southern Europe and the US, where rooms are smaller and buyers want instant heat.

If you're sourcing for a single SKU, go with oil filled. It's a safer bet for the broadest audience. If you have warehouse space for two SKUs, offer both. They don't cannibalize each other; they serve different use cases.

Manufacturing Realities You Should Know

Oil filled radiators are not cheap to ship. A typical 2000W unit weighs around 15 kg packed. A convection heater of the same wattage weighs 4 kg. Freight costs per unit are 3 to 4 times higher for oil filled. That eats into your margin unless you plan for it.

MOQ is another factor. At our factory, standard MOQ is 200 pcs per model. For oil filled radiators, that's a full 40-foot container roughly half full. For convection heaters, 200 pcs fits in a small pallet. If you're testing a market, start with convection. If you're committed, oil filled is fine.

Lead time is similar: 15 to 45 days depending on the finish and whether we need to order the oil-filled element from our supplier. Both types carry CE and RoHS certs. For the UK market, we add UKCA. ERP compliance is standard on all our 2024 models.

A Word on Safety

Both types are safe if built right. But oil filled radiators have a higher risk of oil leaks if the welding is poor. We've seen cheap units from other factories leak at the seam after 2 years. That's a fire hazard and a liability. Ask your supplier for the weld test report and the pressure test certificate. If they can't show you one, walk away.

Convection heaters have exposed elements, so they need a good overheat sensor. We use a dual thermal cutoff on all ours. That's a cheap component, but some factories skip it. Check the wiring gauge too. A 2000W unit on 16 AWG wire is a fire waiting to happen. We use 14 AWG.

The Honest Takeaway

Don't pick a heater type based on what's trending. Pick based on the room your buyer is heating and the shipping cost you can absorb. Oil filled radiators are better for comfort and steady running cost. Convection heaters are better for speed and freight. Both can be sourced well from a CE certified electric heater supplier in China, but you have to ask the right questions. Start with the test room data, then work backwards to your logistics. That's how you avoid a warehouse full of the wrong SKU.