Why Compare Electric Blankets with Space Heaters?
When the temperature drops, many people plug in a portable space heater to warm an entire room. Others reach for an electric blanket that directly warms the body. Both approaches offer comfort but consume electricity differently and have distinct lifespans. Surprisingly, little guidance exists on the exact usage point where the personal warmth of a blanket becomes more economical than heating air with a fan-driven heater. This calculator quantifies that crossover by combining purchase price, expected lifespan, and energy usage into a single model. The output reveals whether investing in a blanket can trim your winter power bills.
Space heaters typically draw 1,500 watts and can heat a small room quickly, yet they waste energy when the goal is simply to keep one person cozy. Electric blankets use a fraction of that power, often around 100 watts, but they carry their own cost and eventually wear out. Consumers rarely calculate whether frequent heater usage justifies buying a blanket instead. This calculator exposes how many hours per season must be logged before the blanket's lower energy consumption compensates for its purchase price and shorter lifespan.
Deriving the Formula
The seasonal cost of a blanket equals its annualized purchase price plus electricity. Let B be the blanket cost, B_l its lifespan in seasons, B_w its power in watts, H the heater cost, H_l the heater lifespan in seasons, H_w the heater power, R the electricity rate, and t the hours of use per season. The per-season blanket cost is B/B_l + (B_w/1000)×R×t, while the heater cost is H/H_l + (H_w/1000)×R×t. Setting these equal and solving for t yields:
If the denominator is zero or negative—meaning the blanket uses no less power than the heater—the blanket can never recoup its cost through energy savings. The calculator checks for this condition and warns the user.
Worked Example
Suppose a blanket costs $60, lasts five winters, and draws 100 watts. A space heater costs $40, lasts eight winters, and draws 1,500 watts. With electricity at $0.15 per kWh, the blanket's per-season ownership cost is $12, while the heater's is $5. The energy cost per hour is $0.015 for the blanket and $0.225 for the heater. Plugging these figures into the formula yields a break-even of roughly 46 hours per season. If you use supplemental heat for fewer hours, the blanket's higher purchase cost outweighs its efficiency; beyond that threshold, the blanket becomes the thriftier choice.
Scenario Table
| Hours per Season | Blanket Total Cost | Heater Total Cost |
|---|---|---|
| 20 | $15 | $9.50 |
| 40 | $18 | $14.00 |
| 80 | $24 | $23.00 |
The table demonstrates how energy costs dominate as usage rises. At low hours the heater is cheaper despite its appetite, but heavy use quickly tilts the balance toward the blanket.
Why This Matters
Electric bills often spike in winter, and small behavior changes can yield outsized savings. By quantifying the benefit of warming yourself directly instead of the surrounding air, this calculator encourages energy-efficient habits. People working from home, students in dorms, or anyone who spends long periods stationary can determine whether a blanket investment pays off. The tool also helps environmentally conscious users gauge the emissions impact of their heating choices by revealing the energy differential.
Limitations and Assumptions
The model assumes constant power draw for both devices, though heaters frequently cycle on and off while blankets may have multiple heat settings. It ignores safety considerations, comfort preferences, and the possibility of heating only part of a room. The lifespan figures are averages and may vary with usage and product quality. Additionally, some utilities offer tiered or time-of-use pricing that could alter the economics. Despite these limitations, the calculator provides a useful approximation for individuals seeking to minimize winter energy costs.
Related Calculators
For broader heating decisions, see the space heater vs central heating cost calculator and explore energy management with the smart thermostat savings estimator.