A 1500 watt electric heater produces about 5,120 BTU/h and comfortably heats one room up to roughly 150–175 square feet. It’s the upper limit of a standard US 15A circuit: 1500W at 120V draws 12.5 amps, which is why nearly every full-size portable heater stops there. Pick a bigger one and you’ll trip the breaker. The real choice isn’t wattage — it’s which type suits the room you’re warming.
Volts, Amps, And Room Size
Output is identical across every 1500W heater — about 5,120 BTU/h — so your decision hinges on power supply, mounting, and heat delivery.
Room size is where buyers get burned. Cadet’s 1500W wall heaters are rated for 175 square feet — an average bedroom or small home office. Portable infrared units land closer to 150 square feet. Manufacturers assume an insulated room with an 8-foot ceiling, so an uninsulated garage or a room with tall windows will feel colder than the number suggests.
Which Type Fits Your Room?
- Baseboard wall heaters — hardwired, mounted low, quiet. The Cadet Register RMC151W runs 120V at 12.5A and covers 175 sq ft. Cadet notes a thermostat is required and sold separately on register-style models.
- Compact wall heaters — hardwired, about 12 x 9 x 5 in. Complete Cadet Com-Pak units (CSC151TW, CSC152TW) ship with the thermostat included; the 240V version draws 6.3A instead of 12.5A.
- Portable infrared — plugs into a standard 110V three-prong outlet. The Dr Infrared Heater DR-968 is 1500W, 5200 BTU, and runs at 39 dB, quieter than normal conversation.
- Wall or ceiling infrared — the Dr. Heater DR-238 is IP55 rated indoor/outdoor with a mounting bracket and 900W, 1200W, and 1500W settings.
| Model | Type & Power | Coverage |
|---|---|---|
| Cadet Com-Pak CSC151TW | Hardwired wall, 120V / 12.5A | 175 sq ft |
| Cadet Com-Pak CSC152TW | Hardwired wall, 208/240V / 6.3A | 175 sq ft |
| Cadet Register RMC151W | Hardwired baseboard wall, 120V / 12.5A | 175 sq ft |
| Dr Infrared DR-968 | Portable infrared, 120V, 5200 BTU | ~150 sq ft |
| Dr Infrared DR-978 | Portable hybrid, 1500W / 1000W ECO | Small rooms |
| Dr. Heater DR-998 | Portable, 120V, 5200 BTU/h | 150 sq ft |
| Dr. Heater DR-238 | Wall/ceiling, IP55, 900–1500W | Patio & garage |
Portable Or Hardwired
A hardwired wall heater needs an electrician and a dedicated circuit but frees up floor space and never needs hauling. A portable unit needs only an outlet and moves with you. If you’re renting, portable infrared is the only realistic path — you’re not running 240V wiring through a rental.
Safety features matter too. The DR-998, rated for 150 square feet, includes auto shut-off and a tip-over switch — the two features you want with kids or pets. For a garage, patio, or covered porch, the DR-238’s IP55 rating tolerates moisture that would ruin an indoor-only heater. Once you’ve narrowed the type, our roundup of tested 1500 watt electric heaters puts the current picks in one place.
What It Costs To Run
This is why ECO and low settings matter: the DR-978’s ECO mode cuts to 1000W, and the DR-238 steps down to 1200W or 900W. Running 900W for six hours costs meaningfully less than 1500W, and for a small closed room the lower setting often holds temperature fine.
Cadet’s spec sheets back the efficiency point for wall units: Com-Pak and Register models produce the same 5,120 BTU/h as portable infrared heaters, so a hardwired wall heater on a thermostat isn’t wasting money on delivery — the difference is convenience, not output. A thermostat turns a heater from on/off into temperature-holding, so a unit with a built-in thermostat generally runs cheaper.
FAQs
Can a 1500 watt heater run on a normal household outlet?
Yes, in most cases. A 120V 1500W heater draws 12.5 amps, within a standard 15A circuit. The catch: the circuit must be dedicated to that heater — sharing with a hair dryer, microwave, or vacuum will trip the breaker.
Is a 240V 1500 watt heater cheaper to run than a 120V one?
No. Both produce the same 5,120 BTU/h at the same wattage, so cost per hour is identical. The 240V version draws 6.3 amps instead of 12.5, easier on wiring and allowing a smaller circuit — but it requires hardwired installation and a dedicated 240V circuit.
How large a room will a 1500 watt heater actually warm?
Expect roughly 150 to 175 square feet in an insulated room with an 8-foot ceiling — a standard bedroom. Larger spaces, uninsulated garages, and rooms with lots of glass stay cooler; treat a 1500W heater as a supplement rather than a replacement there.
References & Sources
- Dr Heater USA. “Dr Infrared Heater DR-968 Original Heater.” Supports the 1500W, 5200 BTU, 39 dB, and $129.99 figures for the DR-968.
- Dr Heater USA. “Dr Infrared Heater DR-978 Dual Heating Hybrid Space Heater.” Source for ECO mode, 1000W/1500W settings, 12.5A draw, and $139.00 price.
- Home Depot. “Original 1500-Watt Infrared Portable Space Heater with Dual Heating System.” Retail listing showing the DR-968 at $112.99.
