Electric blanket vs space heater: compare the job being heated
Warming one person and warming room air require different comparisons. A blanket can have a much smaller electrical load, but the lower number does not show that it provides the room heating you need.
By HomeCost Radar · Reviewed 2026-09-27 · Editorial policy
An assumed four-hour occupied period
Assume a 100 W blanket at either 50% or 100% duty and a 1,500 W resistance space heater at 50% duty. These rows are cost illustrations, not recommendations for duration, overnight use or unattended operation.
| Session | Inputs | kWh/session | Cost/session |
|---|---|---|---|
| Blanket at 50% duty | 100 W × 4 h × 0.5 duty | 0.2000 | $0.03 Range $0.02–$0.05 |
| Blanket at full input | 100 W × 4 h × 1 duty | 0.4000 | $0.06 Range $0.04–$0.09 |
| Space heater at 50% duty | 1,500 W × 4 h × 0.5 duty | 3.0000 | $0.48 Range $0.32–$0.71 |
One session per row. Rates: 2026-07-ytd, published 2026-09-24. The appliance-energy engine prices these assumed loads; the ranges are modeled uncertainty, not product test results. State averages cannot reproduce your utility tariff.
What the example shows: The blanket cases use 0.200 and 0.400 kWh; the heater uses 3.000 kWh. These are different services. The difference cannot be claimed as household savings if room heating continues unchanged.
Define the heating boundary
A personal-warming device affects a small occupied area. A space heater adds heat to room air, while the whole home may still have a separate thermostat. Record which heating system, if any, actually runs less when the personal device is used.
If the central system and space heater keep the same schedules and you add a blanket, electricity rises by the blanket use. A savings claim needs evidence of avoided energy elsewhere, not simply a comparison of device labels.
Use a daily schedule that reflects actual use
Count only the period when the appliance is used according to its instructions. A four-hour assumption repeated on 20 days produces 4 kWh for the lower blanket case or 60 kWh for the heater case. Neither is automatically a 30-day or year-round pattern.
Thermostats change the fraction of time a heater draws full power. A dial setting is not itself a measured duty cycle. Compare a conservative full-input case with a cycling case if you have no measured kWh.
Keep operating instructions ahead of cost optimization
Follow the blanket manufacturer's instructions for placement, condition and permitted use. Check the model for recalls before continued use. Do not extend an operating period simply because the energy estimate appears small.
CPSC advises plugging space heaters directly into wall outlets and keeping them away from combustible materials. The cost comparison does not evaluate electrical condition, circuit capacity or suitability for a particular person.
Frequently asked questions
Does 100 W mean the blanket uses that all the time?
Can the same calculation compare a heat pump?
Sources and assumptions
The worked examples are HomeCost Radar calculations from the stated inputs. Sources below support the concepts identified beside each link; they do not certify our assumed wattages or product savings.
- CPSC: winter heating safety — Space heater placement and direct-to-wall-outlet precautions.
EIA Table 5.6.B supplies the state price. Calculation method and uncertainty.