Oil-Filled Radiator vs Convection Heater: Factory Comparison

Every week a buyer asks me which one to stock: oil-filled or convection. The answer depends on who's buying and what they complain about later. I've watched both come off our lines in Zhongshan since 2009. Here's the honest breakdown.

How they actually heat

A convection panel pulls cold air in at the bottom, heats it over a finned element, and pushes it out the top. It's fast. You feel warmth in two or three minutes. But when the thermostat clicks off, the heat stops almost immediately.

An oil-filled radiator heats diathermic oil inside sealed columns. The metal mass holds that heat. After the element cuts out, the radiator keeps radiating for 15 to 20 minutes. That's the whole difference in one sentence: one is fast and light, the other is slow and heavy.

For a 2000W unit, both draw the same power. The oil-filled one just takes longer to reach full output and longer to cool down.

Where each one wins

Convection panels are the default for wall mounted electric heater programs. They're thin, cheap to ship, and easy to private label. A 1500W panel covers roughly 15 square meters in a decently insulated room. If your customer has a bedroom or office and wants quick heat, convection is the safe pick.

Oil-filled radiators win in drafty or poorly insulated spaces. A garage, a workshop, a basement. The thermal mass keeps the room from swinging hot and cold. Buyers searching for an electric heater for garage use usually end up happier with oil-filled. Same for anyone who wants a silent electric heater. No fan, no click, nothing. Convection panels are silent too, but oil-filled units feel warmer for longer, which matters in cold rooms.

Noise, weight, and shipping

Neither type has a fan, so both are quiet. The difference is weight. A 2000W oil-filled radiator weighs 9 to 12 kg. A 2000W convection panel weighs 3 to 4 kg. That's a real freight cost difference. If you're shipping to Amazon FBA, the convection panel is cheaper per unit to move. If you're selling to a retail chain that wants a premium feel, the oil-filled unit's weight reads as quality.

MOQ on both is 200 pcs standard. Lead time runs 15 to 45 days depending on whether you need custom tooling, packaging, or a new control board.

Thermostats and smart features

Most buyers now want a best electric heater with thermostat, and honestly the thermostat matters more than the heating type. A mechanical bimetal thermostat swings 3 to 4 degrees Celsius. A digital thermostat with a thermistor holds within 1 degree. That's the difference between a customer who's happy and one who returns the unit.

If you're targeting the wifi smart electric heater segment, both types can carry the same module. We've put Tuya-based WiFi boards in convection panels and oil-filled radiators. The oil-filled version needs a higher-rated relay because the element cycles longer, but the app experience is identical.

Safety and certifications

For any unit going to Europe, you need CE and RoHS. UKCA for the UK. ERP compliance for the ecodesign rules on standby power and thermostat accuracy. Don't skip ERP. We've seen shipments held at customs because the standby draw was 0.6W instead of the 0.5W limit.

Tip-over switches and thermal cutouts are non-negotiable on both types. On oil-filled radiators, check the weld quality on the oil columns. A bad weld leaks after a few thermal cycles. We pressure-test every unit at 1.5 times working pressure before it leaves the line.

If you're sourcing from an OEM electric heater manufacturer China, ask for the pressure test report and the ERP test data. A supplier who can't produce those is a supplier who's never shipped to the EU.

Running cost reality

Both types cost the same to run at the same wattage. A 2000W unit at 0.30 EUR/kWh costs 0.60 EUR per hour at full blast. The oil-filled unit cycles less often once the room is warm, so in practice it can use 10 to 15 percent less energy over a long session. That's the only real energy efficient electric heater argument between the two.

If a buyer asks about electric heater vs gas, the answer is simple: electric is cheaper to install and safer indoors, gas is cheaper per kWh in most markets. That's a policy question, not a product one.

What I'd stock

If you're a distributor with limited shelf space, stock both. Convection panels for the entry price point and quick-heat customers. Oil-filled radiators for the premium slot and cold-room customers. Same MOQ, same lead time, same cert path. The tooling cost is the only real difference, and it amortizes fast.

One honest takeaway: don't pick based on which one is cheaper to buy. Pick based on what your customer will complain about in month three. If they hate waiting for heat, sell convection. If they hate the room going cold when the thermostat clicks off, sell oil-filled. The return rate will tell you which one you got right.