Roundup · Low wattage
The honest version first: low wattage buys you low current and a low bill, and it costs you the ability to warm a room. That is a real trade and for some buyers it is the right one.
How this page is funded: we earn a commission if you buy through the links here, at no extra cost to you. Picks are chosen before links are attached, which is why every roundup names something to skip. Full disclosure.
For most people asking, the pick is the Cozy Legs CL at 150 W — 1.25 A, 2.8 cents an hour, and the only heater here whose maker publishes an ETL zero-clearance listing. It warms one person's legs and nothing else. If you need a room held on low wattage, the lowest honest figure in our registry is the Pelonis PSHO06MR6ASB's published 600 W step, which covers about 60 sq ft at 10 watts per square foot.
There is no efficiency trick anywhere in this category: every electric resistance heater converts essentially all of its electricity into heat, so the watts going in are the heat coming out. That makes the whole page a single table.
| Rated power | Current at 120 V | Covers (10 W/sq ft) | Per hour | A month at 8 h/day |
|---|---|---|---|---|
| 150 W | 1.25 A | 15 sq ft | 2.8¢ | $6.60 |
| 170 W | 1.42 A | 17 sq ft | 3.1¢ | $7.48 |
| 600 W | 5.00 A | 60 sq ft | 11.0¢ | $26.41 |
| 750 W | 6.25 A | 75 sq ft | 13.8¢ | $33.01 |
| 900 W | 7.50 A | 90 sq ft | 16.5¢ | $39.61 |
| 1,500 W | 12.50 A | 150 sq ft | 27.5¢ | $66.02 |
Current is watts ÷ 120 V. Coverage is watts ÷ 10 at our baseline sizing rule (average insulation, 8-foot ceiling). Cost is computed at 18.34¢/kWh — the U.S. residential average for June 2026 (EIA, Electric Power Monthly, Table 5.6.A).
Read the coverage column honestly and the category's limit is obvious. Nothing under about 600 W will change a room's temperature, and 600 W only holds a space the size of a small bathroom. What low wattage genuinely buys is in the other two columns: a tenth of the current, and a tenth of the bill.
Four situations, and they are the reason this page exists rather than redirecting you to a 1,500 W heater like everyone else does.
Class one: genuinely low-wattage heaters. 150 to 200 W radiant panels, which is all our registry contains at that level, and all that exists in volume. They have no fan, no moving parts, and no ambition to heat a room. They are the correct answer when the problem is a stationary person rather than a cold space — the same argument the desk heater page makes about 170 W beating 1,500 W at a desk.
Class two: 1,500 W heaters with a published low step. These are room heaters you can choose to run at 600, 750 or 900 W. They are the right buy when you want the option of full output on the coldest night and low output for the other four months — but remember that the moment the element goes to high, your circuit sees the full 12.5 A. If the constraint is a hard amp ceiling rather than a bill, class one is the only honest option.
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 |  Cozy Legs CLA 150 W radiant panel that does one job — warm the legs in a footwell — and is the only heater in this registry whose maker publishes a zero-clearance safety listing on its own page. | The cheapest real under-desk panel | 15 sq ft | 1.3 A | $49.99 · Check on Amazon |
| 2 |  Global Industrial panelFunctionally the same 170 W under-desk panel as the QMark, with the one control the QMark lacks — an adjustable thermostat, so it cycles instead of running until you remember it. | The same panel, with a thermostat | 17 sq ft | 1.4 A | $120.00 · Check on Amazon |
| 3 |  Pelonis PSHO06MR6ASBThe digital Pelonis: all three of its wattages are published, the thermostat sets to the degree between 41 and 95°F, and it rolls on its own wheels. | A radiator with a real set-point and a 24-hour timer | 150 sq ft | 12.5 A | $119.99 · Check on Amazon |
| 4 |  BLACK+DECKER BHDC201The cheapest heater here that publishes its low wattage, which is the only way to know what the economical setting actually costs instead of guessing at it. | A published 750 W low setting for under $25 | 150 sq ft | 12.5 A | $22.99 · Check on Amazon |
| 5 |  De'Longhi HMP1500A micathermic panel is a radiator that gave up its bulk: it radiates like oil-filled and warms up like ceramic, and it is about three inches deep so it can live against a wall. | A slim profile against a wall | 150 sq ft | 12.5 A | $129.95 · 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 cheapest real under-desk panel
A 150 W radiant panel that does one job — warm the legs in a footwell — and is the only heater in this registry whose maker publishes a zero-clearance safety listing on its own page.
| Published specification | |
|---|---|
| Rated power | 150 W at 120 V, 60 Hz (Cozy Products' published figures) |
| Current draw | 1.25 A (150 ÷ 120) — our figure. Cozy Products' page prints 1.3 A, which is the same draw rounded |
| Element | Radiant panel — no fan, no moving parts |
| Thermostat | Built-in; Cozy Products publishes no set-point range, so there is no temperature to choose |
| Controls | An in-cord roller switch |
| Size | Cozy Products publishes the shipping box at 25 x 20 x 2 inches and the weight at 8 lb, but not the panel's own dimensions — so we do not print a panel size |
| Surface temperature | Approximately 130°F (Cozy Products' published figure) |
| Safety | ETL Certified Zero-Clearance — no clearance required, which the maker states on its own page |
| Heat type | Radiant panel |
| Maker’s coverage claim | None published — the coverage figure above is ours |
| Safety listing | Cozy Products publishes an ETL Certified Zero-Clearance rating on its own product page, which is why the panel may sit against a wall or other combustible surface. |
Who it is for
A footwell where the complaint is cold legs, the circuit is already busy, and you want the lowest-draw honest answer rather than a 1,500 W heater in a small box.
What it is not for
Heating a room, or anywhere you need the heater to switch itself off. Without a timer or a set-point it is on until you switch it off at the cord, which makes the [unattended-heater guidance](/safety/overnight) matter more, not less.
Sources for this entry
2 · The same panel, with a thermostat
Functionally the same 170 W under-desk panel as the QMark, with the one control the QMark lacks — an adjustable thermostat, so it cycles instead of running until you remember it.
| Published specification | |
|---|---|
| Rated power | 170 W at 120 V |
| Controls | Adjustable thermostat |
| Dimensions | 22-7/16" W x 14-14/16" H |
| Mounting | Floor mount, compact under-desk design |
| Finish | White |
| Heat type | Radiant panel |
| Maker’s coverage claim | None published — the coverage figure above is ours |
| Safety listing | No listing mark published in the listing text; check the rating plate for the UL or ETL mark. |
Who it is for
The same desk-bound reader as the QMark, who would rather the panel cycled on a thermostat than stayed on until switched off.
What it is not for
Anyone wanting a room warm. It is a leg warmer with a thermostat, and that is the correct expectation to have of it.
3 · A radiator with a real set-point and a 24-hour timer
The digital Pelonis: all three of its wattages are published, the thermostat sets to the degree between 41 and 95°F, and it rolls on its own wheels.
| Published specification | |
|---|---|
| Rated power | 600 W / 900 W / 1,500 W at 120 V (all three published) |
| Thermostat | 41–95°F in 1°F increments |
| Modes | Energy-saving ECO mode |
| Timer | 24 hours |
| Controls | LED touchscreen plus remote |
| Construction | Upgraded M-shaped fins; Pelonis publishes no fin count |
| Maker's noise claim | “Fan-free design ensures ultra-quiet performance” — no decibel figure is published |
| Portability | Universal wheels and handles |
| Safety | Tip-over protection, overheat protection and V0 flame-retardant materials |
| Heat type | Oil-filled |
| Maker’s coverage claim | None published — the coverage figure above is ours |
| Safety listing | Pelonis publishes V0 flame-retardant materials, tip-over protection and overheat protection, but does not name a UL or ETL mark and does not state a child lock. Check the rating plate. |
Who it is for
A bedroom, nursery or study where silence is the requirement and you want to set an actual temperature and a shut-off time rather than a dial position.
What it is not for
Fast heat, or a room much over 150 sq ft on our arithmetic. It is a radiator: it warms slowly and steadily, and that is the design rather than a fault.
Sources for this entry
4 · A published 750 W low setting for under $25
The cheapest heater here that publishes its low wattage, which is the only way to know what the economical setting actually costs instead of guessing at it.
| Published specification | |
|---|---|
| Rated power | 1,500 W high / 750 W low, at 120 V |
| Controls | Four-position switch — off, fan, low, high |
| Thermostat | Adjustable |
| Other modes | Fan-only |
| Safety | Overheat protection and tip-over auto shut-off |
| Heat type | Ceramic (PTC) |
| Maker’s coverage claim | None published — the coverage figure above is ours |
| Safety listing | No listing mark is published in the listing text; check the rating plate for UL or ETL. |
Who it is for
A desk, a home office or a small bedroom where the 750 W setting will do most of the work and the 1,500 W setting is there for the cold snap.
What it is not for
A large or drafty room. At 750 W it covers about 75 sq ft at our sizing rule, and at 1,500 W it is still a personal heater in a small cabinet.
5 · A slim profile against a wall
A micathermic panel is a radiator that gave up its bulk: it radiates like oil-filled and warms up like ceramic, and it is about three inches deep so it can live against a wall.
| Published specification | |
|---|---|
| Rated power | 1,500 W high / 750 W low, at 120 V |
| Element | Mica panel — radiant plus convection, no fan |
| Mounting | Freestanding or wall-mountable |
| Controls | Adjustable thermostat, two heat settings |
| Frost mode | Standby setting holding the room above 41°F |
| Safety | Thermal shut-off, internal tip-over switch, standby setting |
| Heat type | Micathermic |
| 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 room where floor space is tight and fan noise is unwelcome — a small bedroom, a study, a hallway landing.
What it is not for
A nursery or a household with toddlers, unless it is wall-mounted well out of reach. A hot panel at knee height is a burn, not a fire.
And what we did not do: we have not tested these units, owned them, measured them or run them in a room. Everything above is compiled from published manufacturer specifications and live retail listings, with the electrical load, room coverage and running cost computed by us from the published wattage. The full method.
Every roundup on this site names something to skip. It costs us nothing to publish and it is the fastest way to tell whether a buying guide was written for you or for its commission.
Any heater sold as “low wattage” whose low setting is not published
This is the whole category's trick. A 1,500 W heater with an unmarked Low position is a 1,500 W heater as far as your circuit and your bill are concerned, because you cannot cost a setting whose wattage nobody states and you cannot tell whether "low" is 1,200 W or 600 W. Of the heaters we track, only a handful publish their low step as a number. Those are the only ones on this page, and the rest are a guess with a price tag.
A 400-600 W heater advertised as a room heater
At 10 watts per square foot a 500 W heater covers 50 sq ft — a walk-in closet, a small bathroom, a pump house. Sold against a photograph of a living room it is simply mis-sold, and the giveaway is a coverage claim with no wattage arithmetic behind it. A 600 W setting on a 1,500 W radiator is a different proposition entirely, because the radiator can step up when the room needs it.
It does not make a heater cheaper to run per unit of heat — 600 W for two hours and 1,200 W for one hour cost exactly the same, because both are 1.2 kWh. The saving is real only when the lower setting actually holds the room, so that the heater spends fewer watt-hours rather than the same ones more slowly. Why no heater is cheaper to run is the full version of that argument, and the energy-efficient roundup picks on the same three levers: wattage, thermostat accuracy and hours.
It also does not change the safety rules. A 150 W panel still needs clearance from combustibles, still should not live under a rug, and still belongs plugged into a wall rather than a power strip — the current is lower but the three-foot rule is about surface temperature, not amperage. The one thing it genuinely does improve is the circuit arithmetic, which is the leading cause of the complaint on the tripping-breaker page.
A 150 W radiant panel, provided you want to warm a person rather than a room. It draws 1.25 A, costs about 2.8 cents an hour, and covers about 15 sq ft at 10 watts per square foot — which is a footwell. Nothing under about 600 W will raise a room's air temperature.
It will hold about 50 sq ft at 10 watts per square foot with average insulation and an 8-foot ceiling — a small bathroom or a large closet. In a bedroom it will take the edge off and no more, and in a drafty room the honest figure falls to about 40 sq ft.
Watts divided by 120. A 150 W panel is 1.25 A, a 600 W setting is 5 A, a 750 W setting is 6.25 A and a full 1,500 W heater is 12.5 A — against the 12 A a 15 A branch circuit may carry continuously. That last comparison is why low wattage is often a circuit decision rather than a cost one.
Per hour, yes and exactly in proportion: 750 W costs half of what 1,500 W costs, with no efficiency penalty. Per unit of heat, no — all electric resistance heaters are essentially 100% efficient, so the only real saving comes when the lower setting is enough to hold the room.
The cost side is manageable: 150 W continuously is about $19.81 a month and 600 W is about $79. The safety guidance does not change with wattage, though — the U.S. Fire Administration's advice is to switch any portable heater off when you leave the room, and a panel with no timer and no set-point has to be switched off by hand.
Whichever one fits the amp budget you have left after the fridge and the converter, which is an arithmetic question rather than a product one. A 150 W panel is 1.25 A and is almost always affordable; a 1,500 W heater is 12.5 A and on a 30 A hookup it is half your service.
A desk does not need a room heater. 170 W of radiant panel against 1,500 W — the arithmetic and the picks.
All electric heaters are 100% efficient. These are picked on the three things that actually cut the bill.
Where the 750 / 1000 / 1500 W tiers come from, and why 1500 W is a hard ceiling on a U.S. outlet.
12.5 A against a 12 A continuous limit — the arithmetic nobody publishes, and what to do about it.
Every heater here is electric, so the outage stops it. What a generator and a battery each have to be rated for.
A 1,500 W heater is half a 30 A pedestal. The amp arithmetic first, then the units with a real low setting.