Electric Blanket vs Heater: Which Uses More Electricity in South Africa?
Compare the electricity consumption and costs of electric blankets and space heaters to find the most cost-effective way to stay warm.
The Short Answer
Which option costs less depends on how you use them and your specific appliances. Electric blankets typically use lower wattage but operate for many hours. Space heaters use higher wattage but may heat multiple people at once. The actual cost depends on operating hours, appliance wattage, thermostat cycling, and your electricity tariff.
Typical electric blanket wattage: 60-200 watts
Typical space heater wattage: 750-2,500 watts
Key difference: Blankets use much less power but run for longer periods; heaters use more power but may serve multiple people
Note: Total electricity cost depends on each appliance's wattage, how long it operates, and whether it has features like thermostats that reduce power draw.
How Electric Blankets and Space Heaters Work Differently
How an Electric Blanket Works
An electric blanket is a blanket with a built-in heating element that warms the fabric. The blanket heats the person using it directly, with minimal heat loss to the surrounding air. Most electric blankets have adjustable heat settings (high, medium, low) that reduce power draw at lower settings. They are designed to run for extended periods while you sleep or rest.
Typical wattage: 60-200 watts depending on size and heating level. Lower settings use less power than high settings.
How a Space Heater Works
A space heater warms the air in a room using an electric heating element and often a fan to distribute heat. Space heaters are designed to heat an entire room or large area. They have higher power ratings because they must heat a much larger volume of space. Most space heaters draw their full rated power continuously, or use a thermostat to cycle on and off.
Typical wattage: 750-2,500 watts. Space heaters draw significantly more power than blankets because they heat the entire surrounding air.
Usage Patterns and Operating Hours
Electric blankets typically run for 8-10 hours per night while someone sleeps. Space heaters are often run for shorter periods during the day or evening, or sometimes all day during very cold weather. The total hours of operation significantly affect electricity consumption. A blanket running 8 hours nightly uses a different amount than a heater running 4 hours daily.
Why Electricity Consumption Varies
Electric Blanket Variations
- Blanket size: Single blankets (60-100 W) use less power than double blankets (100-200 W)
- Heat setting: High heat settings use full power; medium and low settings reduce power draw significantly
- Operating hours: Some people use blankets for 8+ hours nightly; others use them only occasionally
- Blanket age: Older blankets may have worn insulation or heating elements
- Type of blanket: Underblankets, overblankets, and blankets with controllers vary in wattage
Space Heater Variations
- Heater wattage: Small heaters (750-1,500 W) use less power than large heaters (2,000-2,500 W)
- Heater type: Oil heaters, fan heaters, and radiant heaters have different cycling characteristics
- Thermostat: Heaters with working thermostats cycle on and off, reducing average power draw; continuous-operation heaters use full power
- Operating hours: Heaters may run 2-8 hours daily depending on weather and preference
- Room size: Heating a large room requires longer operation than heating a small bedroom
- Number of people: A heater can warm multiple people at once, while a blanket warms only one
Appliance Settings and Thermostat Cycling
Electric blankets with adjustable heat settings (high, medium, low) use less power at lower settings. Space heaters with thermostats cycle the heating element on and off to maintain room temperature. These cycling effects significantly affect total electricity consumption. A blanket on low for 8 hours may use similar or less electricity than a heater running continuously for 4 hours.
How to Calculate Electricity Consumption and Cost
The Basic Formulas
kWh = (Watts × hours) ÷ 1,000
Cost = kWh × tariff per kWh (R/kWh)
To compare blanket and heater costs, you need: appliance wattage (at the setting you use), actual operating hours, and your electricity tariff.
Example: Electric Blanket Calculation
Assumptions:
- Electric blanket: 120 watts (medium setting)
- Operating time: 8 hours per night
- Hypothetical tariff: R2.50/kWh (NOT current)
Nightly and Monthly Calculation:
kWh per night = (120 W × 8 hours) ÷ 1,000 = 0.96 kWh
Cost per night = 0.96 kWh × R2.50 = R2.40
Cost per month (30 nights) = R2.40 × 30 = R72.00
Example: Space Heater Calculation
Assumptions:
- Space heater: 1,500 watts
- Operating time: 4 hours per day (evening and morning)
- Hypothetical tariff: R2.50/kWh (NOT current)
Daily and Monthly Calculation:
kWh per day = (1,500 W × 4 hours) ÷ 1,000 = 6 kWh
Cost per day = 6 kWh × R2.50 = R15.00
Cost per month (30 days) = R15.00 × 30 = R450.00
Hypothetical Monthly Warmth Cost Comparison
⚠️ Assumptions: These examples assume specific usage patterns with a hypothetical electricity tariff of R2.50/kWh (NOT a current real-world tariff). Your actual costs depend on your appliances' actual wattage, your actual usage hours, appliance settings, and your actual electricity tariff.
| Appliance & Usage | Wattage | Daily Hours | Monthly kWh | Monthly Cost |
|---|---|---|---|---|
| Electric Blanket (low setting) | 60 W | 8 hours | 14.4 kWh | R36.00 |
| Electric Blanket (medium setting) | 120 W | 8 hours | 28.8 kWh | R72.00 |
| Electric Blanket (high setting) | 150 W | 8 hours | 36 kWh | R90.00 |
| Space Heater (1,500W, 4 hours/day) | 1,500 W | 4 hours | 180 kWh | R450.00 |
| Space Heater (1,000W, 4 hours/day) | 1,000 W | 4 hours | 120 kWh | R300.00 |
| Space Heater with thermostat (1,500W, 4 hours/day, 50% cycling) | 1,500 W | 4 hours avg | 90 kWh | R225.00 |
Key observation: Based on these hypothetical examples, an electric blanket costs significantly less to operate per month (R36-R90) compared to a space heater (R225-R450). However, these are different use cases—a blanket warms one person in bed, while a heater warms an entire room. If you need to heat a room for multiple people or throughout the day, a heater may be necessary despite higher costs. The most cost-effective approach depends on your specific needs and usage patterns.
Note: A space heater with a working thermostat can reduce costs significantly through thermostat cycling. Your actual costs will vary based on your specific appliances, settings, usage hours, and electricity tariff.
Practical Ways to Reduce Winter Electricity Costs
Use an Electric Blanket for Personal Warmth
For personal warmth while in bed, an electric blanket on a low or medium setting uses significantly less electricity than heating an entire room with a space heater. This is often the most cost-effective option for nighttime warmth.
Set Blanket to Low or Medium Heat
Electric blankets with adjustable heat settings (high, medium, low) reduce power draw at lower settings. Medium heat is often sufficient for comfort while using 20-40% less power than high heat.
Heat Only the Room You Use
If you need a space heater, use it only in the room where you spend time. Close doors to unused rooms. Heating only one bedroom costs significantly less than heating an entire house.
Improve Insulation and Block Drafts
Weather stripping, heavy curtains, and sealing drafts around windows and doors reduce heat loss. Better insulation means your blanket or heater doesn't need to work as hard to maintain comfort.
Choose a Space Heater with a Thermostat
A space heater with a working thermostat cycles the heating element on and off to maintain room temperature. This can reduce average power draw by 30-50% compared to a heater that runs continuously.
Turn Off Heating When Not Needed
Don't leave a blanket or heater running in empty rooms or when you leave home. Turn them off when they're not needed. This is one of the most effective ways to reduce heating costs.
Use Heating During Off-Peak Hours
Some municipalities offer lower tariffs during off-peak hours. Schedule heating for these periods when possible to reduce costs.
Layer Clothing and Bedding
Wear warm clothing and use multiple blankets (including non-electric blankets) to reduce your reliance on heating appliances. This layering approach can allow you to use blankets and heaters at lower settings or for shorter periods.
Which Is Cheaper: Electric Blanket or Space Heater?
The answer depends on your specific situation and needs. An electric blanket typically costs less to operate per month (R36-R90 in hypothetical examples) because it uses much lower wattage and heats only one person. A space heater costs more (R225-R450 in examples) because it uses higher wattage to heat an entire room. However, the choice depends on whether you need to heat just yourself or an entire space, and for how long.
Key factors that determine which is cheaper for you:
- Whether you need to heat just yourself or an entire room/multiple people
- How many hours per day you need heating
- Appliance wattage and heat settings (for blankets) or thermostat behavior (for heaters)
- Room insulation and size
- Your electricity tariff
- Whether appliances have thermostat cycling or adjustable settings
Strategy for South Africa: For personal warmth at night, an electric blanket on low or medium setting is often the most cost-effective option. For heating a room during the day or for multiple people, a space heater with a working thermostat may be necessary despite higher costs. Many households benefit from using both strategically—a blanket for bedroom warmth and a thermostat-equipped heater for living spaces on cold days. Your actual heating costs depend on your specific appliances, usage patterns, and local electricity tariff.
Calculate Your Winter Heating Costs
Use our interactive electricity calculator to estimate your actual blanket or heater costs. Enter your appliance's wattage (at the setting you use), actual operating hours per day, and your electricity tariff for a personalized estimate.
Calculate your winter heating costElectric Blanket Cost Guide
Comprehensive guide to understanding electric blanket electricity costs.
Space Heater Cost Guide
Comprehensive guide to understanding space heater electricity costs.
Understanding Electricity Tariffs
Learn why tariffs vary across South Africa.
Electricity Cost Calculator
Calculate costs for any appliance using your actual tariff.
Frequently Asked Questions
Is an electric blanket cheaper than a heater?
For personal warmth, an electric blanket is typically cheaper because it uses 60-200 watts compared to 750-2,500 watts for a space heater. In hypothetical examples, an electric blanket costs R36-R90 per month while a space heater costs R225-R450. However, these serve different purposes—a blanket warms one person, while a heater warms a room for multiple people. The cheaper option depends on your specific needs.
Does an electric blanket use a lot of electricity?
No, electric blankets are relatively efficient. They typically use 60-200 watts depending on size and heat setting. Even at high heat, an electric blanket uses much less power than a space heater (which uses 750-2,500 watts). Operating an electric blanket for 8 hours costs approximately R2-R3 per night in hypothetical examples.
Using a lower heat setting (medium or low) further reduces power consumption while still providing comfort.
How much electricity does a heater use?
Space heaters typically use 750-2,500 watts depending on size and type. Operating a 1,500-watt heater for 4 hours daily uses about 180 kWh per month, costing R450 at R2.50/kWh (hypothetical tariff). A heater with a working thermostat can reduce this to about 90 kWh per month by cycling on and off.
Check your heater's nameplate for wattage and multiply by operating hours, divide by 1,000 to get kWh, then multiply by your actual tariff (R/kWh) from your electricity bill.
How can I calculate the cost of running my electric blanket?
Use this formula: kWh = (Watts × hours) ÷ 1,000, then Cost = kWh × your tariff (R/kWh).
For example, a 120-watt blanket on medium setting running 8 hours: (120 × 8) ÷ 1,000 = 0.96 kWh. At R2.50/kWh, that's R2.40 per night, or about R72 per month. Check your blanket's wattage on the nameplate (or control box) and your tariff on your electricity bill. Note: actual wattage at each heat setting varies by blanket model.
Disclaimer
Electricity costs vary by tariff, provider, municipality, tariff structure and usage circumstances. The examples on this page are for illustration only and should not be treated as current tariff information.