Oil-Filled Radiator vs Convection Heater: A Factory Comparison

Every January, our inbox fills with the same question from distributors: should I stock oil-filled radiators or convection panels? The answer depends on where the heater ends up. After 15 years building both, here's the honest breakdown.

How They Actually Work

Oil-filled radiators use a sealed diathermic oil reservoir. A heating element warms the oil, the oil warms the fins, and the fins radiate heat into the room. They heat up slowly, maybe 15 to 20 minutes to full output, but they keep giving off warmth after the thermostat cuts power. That thermal mass is the whole point.

Convection heaters, including our wall-mounted panels, use a metal or ceramic element that heats air directly. Cool air enters the bottom, warms, rises out the top. They hit full temperature in 60 to 90 seconds. They also lose that heat the moment you switch them off.

That difference drives every buying decision downstream.

Where Each One Wins

If a buyer is sourcing for an electric heater for large room applications, convection wins on raw air turnover. A 2000W panel can move meaningful volume in a 30-square-meter space. Oil-filled units at the same wattage feel weaker in open-plan rooms because radiant heat doesn't carry across distance.

Flip it for a bedroom. The silent electric heater argument is real. Oil-filled radiators have no fan, no clicking relay if you spec a triac controller, and zero airflow noise. Convection panels with a fan assist will always have some hum. For a home office or nursery, buyers usually go oil-filled.

Garages and workshops are a different animal. Radiant infrared and fan-forced convection dominate there. Oil-filled radiators are too slow to be useful when you're only in the space for two hours. We tell buyers not to waste shelf space on oil-filled for the electric heater for garage category unless it's a permanently heated space.

The Running Cost Conversation

Here's where buyers get confused. A 1500W oil-filled radiator and a 1500W convection panel draw the same power at full load. The difference is duty cycle. Oil-filled units cycle on and off more because of thermal mass. In a well-insulated room, that can mean 20 to 30 percent less energy over a heating season.

But in a drafty room, the oil-filled unit never gets ahead. It runs flat out and costs the same as convection. So the energy efficient electric heater claim depends entirely on the building, not the product. Any supplier telling you otherwise is selling a story.

Certifications and Compliance

For EU buyers, both product types need CE marking plus ERP Lot 20 compliance. That means a programmable thermostat, adaptive start, and open-window detection on most models. UKCA applies for the UK market separately. RoHS covers the electronics.

For electric heater for bathroom IP24 applications, neither oil-filled nor standard convection works without a sealed enclosure. IP24 is the minimum. We build a specific wall-mounted panel line for this, and it adds roughly 8 to 12 percent to unit cost.

MOQ, Lead Time, and What Buyers Actually Order

Our standard MOQ is 200 pcs per model per voltage. Lead time runs 15 to 45 days depending on finish, packaging, and whether you need custom thermostats or Wi-Fi modules.

A wifi smart electric heater version adds about 4 to 6 USD to BOM cost at 200 pcs. Most private-label buyers start with one smart SKU and two analog SKUs to cover price tiers.

For OEM electric heater manufacturer China sourcing, the split we see most often is 60 percent convection panels, 40 percent oil-filled. Convection is cheaper to ship, lighter, and easier to stack in Amazon FBA warehouses. Oil-filled units are heavier, cost more to freight, but command higher retail prices and better margins.

Safety Points Buyers Ask About

Tip-over switches, thermal cutoffs, and V-0 rated plastics are non-negotiable. For electric heater safety tips content on your listing, mention that oil-filled radiators stay hot for 20 minutes after shutdown. That's a real burn risk with kids and pets. Convection panels cool faster but have exposed elements on some cheap designs. Don't source those.

One Honest Takeaway

There is no universal winner. If your market skews toward bedrooms, offices, and long-duration heating, stock oil-filled. If it's garages, workshops, quick-hit heating, and price-sensitive Amazon listings, convection panels move faster. The smart move is to carry both and let the customer's room decide. Anyone who tells you one product covers every use case hasn't spent a winter on the factory floor.