Comparison · Types
The two types people cross-shop when they have ruled out fan heaters — and they are almost perfect opposites.
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An infrared heater warms objects and people directly and is effective within seconds, but only in its line of sight. An oil-filled radiator warms the whole room slowly and evenly and keeps radiating after it cuts off. At the same wattage they cost exactly the same to run.
| Infrared quartz | Oil-filled radiator | |
|---|---|---|
| How the heat reaches you | Radiation — direct to objects and people | Convection from a warm steel body |
| Time to feel it | Seconds | Twenty to thirty minutes |
| Heats the air? | Barely, and deliberately so | Yes — that is the mechanism |
| Works behind furniture / round corners | No | Yes |
| Noise | Most have a fan | None — no moving parts at all |
| Residual heat after cut-off | Essentially none | Ten to twenty minutes, tapering |
| Best in | Drafty, tall, leaky or briefly-occupied rooms | Sealed, small-to-average rooms you sit in for hours |
| Cost per hour at 1,500 W | 27.5¢ | 27.5¢ — identical |
| Output at 1,500 W | 5,118 BTU/h | 5,118 BTU/h — identical |
Both at 1,500 W. Every cost and coverage figure here is computed from wattage, not quoted from a maker.
Both categories are marketed on efficiency and neither deserves it. Every electric resistance heater converts essentially 100% of the electricity it draws into heat in your room, so at 1,500 W both of these cost 27.5 cents an hour at the U.S. average residential rate and both produce 5,118 BTU/h. There is no version of this comparison where one of them is cheaper per hour than the other.
| Wattage | Per hour | 1 h | 4 h | 8 h |
|---|---|---|---|---|
| 750 W | 13.8¢ | $0.14 | $0.55 | $1.10 |
| 1,500 W | 27.5¢ | $0.28 | $1.10 | $2.20 |
Computed at 18.34¢/kWh — the U.S. residential average for June 2026 (EIA, Electric Power Monthly, Table 5.6.A, released August 26, 2026). Your rate is on your own bill; substitute it and the arithmetic still holds. Figures assume full output for the whole period.
Where a real difference in your bill can appear is in hours run, and the two types get there by opposite routes. Infrared can make you comfortable in a cold garage in five minutes, so you run it briefly. An oil-filled radiator with a good thermostat holds a bedroom steady without swinging, so it cycles off more of the time. Both are usage effects, both are conditional on the room, and neither is a property of the device. The full argument is on the cheapest space heater to run.
The rate behind every figure on this site
18.34¢per kilowatt-hour
U.S. residential average for June 2026. EIA, Electric Power Monthly, Table 5.6.A, released August 26, 2026.
This is the most recent month EIA has published. Residential rates move seasonally and vary enormously by state — from roughly a dime per kilowatt-hour in parts of the South to more than 40¢ in Hawaii — so treat it as a national reference point, not as your rate.
This is the distinction that decides the purchase, and it is not usually how the comparison is framed.
Infrared heats you. Stand in front of it and you are warm almost immediately, because the radiation is landing on you rather than on the air. Walk four feet to the left, or turn your back, or put a chair between yourself and the heater, and the warmth stops — completely and instantly. The air in the room has barely changed temperature, so there is nothing to fall back on.
An oil-filled radiator heats the room. It takes half an hour to do anything you can feel, and during that half hour you will wonder whether it is working. After that, the whole room is warm, including behind the sofa and the far side of the bed, and it stays that way for a while after the element cuts out.
Oil-filled radiators are silent. Not quiet — silent. There is no fan, no pump and no moving part of any kind; the only sound one can make is the occasional tick of expanding metal.
Infrared is often assumed to be silent too, because radiant heat itself makes no noise. In practice most portable infrared cabinets include a fan to move the radiant heat off the quartz tubes and into the room, and that fan is audible. The Dr Infrared DR-968 is one of the very few units in this entire category that publishes a decibel figure at all — 39 dB — which is quiet for a fan-driven heater but is not nothing. If silence is an absolute requirement, oil-filled wins by default and it is not close.
Neither type escapes the arithmetic. At 10 watts per square foot with average insulation and an 8-foot ceiling, 1,500 W covers 150 sq ft, whichever technology delivers it.
| Room size | Watts needed | BTU/h | Plug-in heaters |
|---|---|---|---|
| 100 sq ft | 1,000 W | 3,412 | 1 |
| 150 sq ft | 1,500 W | 5,118 | 1 |
| 200 sq ft | 2,000 W | 6,824 | 2 (different circuits) |
| 300 sq ft | 3,000 W | 10,236 | 2 (different circuits) |
Computed as square feet x 10 W x insulation factor x (ceiling / 8 ft), for an average heated room — 10 W/sq ft, 8 ft ceiling. Heater count assumes the 1,500 W plug-in ceiling.
The caveat is the one from the infrared section above: in the leaky, tall spaces where you would choose infrared, the table is answering “can this raise the air temperature of the whole room” and the answer is usually no. That is not an argument against buying it. It is an argument for being clear that you are buying personal warmth rather than a warm building.
The two units below are the clearest examples of each type in our registry — one that publishes an unusual amount of hard data for an infrared cabinet, and one that is the type's silence argument made physical.
Ranked for fit, not for hype. Coverage and current draw are computed from each unit’s published wattage. Tap a row for the full write-up, or go straight to the listing.
| # | Product | Best for | Covers | Draw | Price |
|---|---|---|---|---|---|
| 1 |  Dr Infrared DR-968The one listing in this category that publishes its amp draw and its noise level, which is exactly the arithmetic everyone else leaves you to do — 12.5 A and 39 dB, both stated. | The published numbers | 150 sq ft | 12.5 A | $112.99 · Check on Amazon−10% |
| 2 |  De'Longhi TRD40615TNo fan, so no noise and no moving dust — and the sealed oil keeps radiating after the element cuts out, which is why an oil-filled unit feels steadier than a ceramic one at the same wattage. | Silence, and a bedroom | 150 sq ft | 12.5 A | $162.28 · Check on Amazon |
Coverage computed at 10 W/sq ft, average insulation, 8 ft ceiling. Draw computed as watts ÷ volts. Neither figure is a manufacturer claim.
Top pick · The published numbers
The one listing in this category that publishes its amp draw and its noise level, which is exactly the arithmetic everyone else leaves you to do — 12.5 A and 39 dB, both stated.
| Published specification | |
|---|---|
| Rated power | 1,500 W at 120 V |
| Current draw | 12.5 A (published) |
| Noise | 39 dB (published) |
| Element | Infrared quartz tube plus PTC |
| Thermostat | Electronic, 50–85°F |
| Other | 12-hour auto-off timer, IR remote, caster wheels, 19 lb |
| Heat type | Infrared quartz |
| Maker’s coverage claim | None published — the coverage figure above is ours |
| Safety listing | No listing mark published in the listing text; check the cabinet's rating plate for the UL or ETL mark. |
Who it is for
A reader who wants to compute the load rather than trust a claim: the published amp draw and decibel figure make it the easiest unit on this site to check.
What it is not for
A 15 A circuit shared with anything else, and not a small room where a 19 lb cabinet on wheels is in the way.
2 · Silence, and a bedroom
No fan, so no noise and no moving dust — and the sealed oil keeps radiating after the element cuts out, which is why an oil-filled unit feels steadier than a ceramic one at the same wattage.
| Published specification | |
|---|---|
| Rated power | 1,500 W at 120 V |
| Controls | Mechanical, with a programmable 24-hour timer |
| Fluid | Permanently sealed diathermic oil — never needs refilling |
| Maker's claim | Up to 75% more radiant surface area |
| Mobility | Front and rear handles, snap-on wheels |
| Heat type | Oil-filled |
| Maker’s coverage claim | None published — the coverage figure above is ours |
| Safety listing | No listing mark published in the listing text; verify the UL or ETL mark on the rating plate. |
Who it is for
A bedroom, a nursery at a safe distance, or anywhere the fan noise of a ceramic heater is the actual problem you are trying to solve.
What it is not for
Fast heat, and not a room you only occupy for twenty minutes. It also should never be tucked beside a bed or curtain — hot surface, 3-foot rule.
Neither. At the same wattage they cost exactly the same — about 27.5 cents an hour at 1,500 W and the U.S. average rate — because every electric resistance heater is essentially 100% efficient. Differences in your bill come from how many hours each one ends up running, not from the technology.
Infrared makes you feel warm in seconds, but it barely raises the room's air temperature. An oil-filled radiator takes twenty to thirty minutes to change how a room feels, and then warms all of it. Which is 'faster' depends on whether you want a warm person or a warm room.
Oil-filled, without much argument. It has no fan and makes no noise at all, it has no exposed glowing element, and it holds a steady temperature through the night rather than cycling hard. Most portable infrared units have an audible fan.
Yes, clearly. A garage is uninsulated and leaky, so warming its air is close to impossible with a plug-in heater, while radiant heat warms you directly regardless of how much cold air is moving around. That said, no 1,500 W heater will warm a whole two-car garage — that arithmetic is on the garage roundup.
Yes, for roughly ten to twenty minutes, tapering the whole time. It smooths out temperature swings, which is a genuine comfort benefit. It is not free heat — every joule came out of the wall at the same rate as everything else.
Silent and slow against fast and audible — and what the thermal-mass argument is really worth.
Heating the air versus heating the things in it — the distinction under every other comparison.
Heats you, not the air — which is why it wins in drafty rooms and loses behind the sofa.
The quietest type there is, and the one with the most marketing to strip away. Four picks, silence first.
Heats you rather than the room — excellent where every other type struggles, and the shadowing problem.
Silent by design, not by adjective — the fanless types, plus the one unit that publishes a dB figure.