What Uses Watts in Your Home
Electricity usage is calculated in kilowatt-hours. A kilowatt-hour is 1,000 watts used for one hour. As an example, a 100-watt light bulb operating for ten hours would use one kilowatt-hour.
How to calculate electric usage cost:
1. Volts x Amps = Watts
2. Watts รท 1,000 = Kilowatts (kW)
3. Kilowatts (kW) x Hours of Use = Kilowatt Hours (kWh)
4. Kilowatt Hours (kWh) x kWh rate = Cost of Usage
5. Add TVA Power Cost Adjustment charge per kWh
Below are some examples of electrical appliances found in most homes. These examples are using a 10 cents per kWh rate.
| Appliance/Equipment | Avg. Usage | Monthly kWh | Cost/Month |
| Comfort & Health | |||
| Air Conditioner – Window 12,000 BTU (1,400 Watts) |
8 hours/day | 341 | $34.10 |
| Dehumidifier (257 Watts) | 12 hours/day | 94 | $9.40 |
| Fan – Furnace (300 Watts) | 7 hours/day | 64 | $6.40 |
| Fan – Ceiling (125 Watts) | 12 hours/day | 46 | $4.60 |
| Fan – Attic (1000 Watts) | 2 hours/day | 61 | $6.10 |
| Heat Pump (Average Rating) (1,800 sq. ft. house) 7.7 HSPF* |
daily | Average Annual Cost | $841.50 |
| Heat Pump (High Efficiency) (1,800 Sq. ft. house) 8.5 HSPF* |
daily | Average Annual Cost | $762.30 |
| Heat Pump (Geothermal) (1,800 sq. ft. house) Equiv. 13.3 HSPF* |
daily | Average Annual Cost | $487.10 |
| Heater – Portable (1500 W) | 8 hours/day | 365 | $36.50 |
| Humidifier (177 Watts) | 8 hours/day | 43 | $4.30 |
| Water Heater (4500 W) | 3 hours/day | 411 | $41.10 |
| Hair Dryer (1,000 W) | 15 min./day | 7.6 | $0.76 |
| *Heating Season Performance Factor (an efficiency rating) **Based on 4,296 Heating Degree Days. Cooling costs would be approximately 40% of total energy costs. |
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| Food Prep. & Preservation | |||
| Blender/Food Processor (400 Watts) | 1 hour/week | 2 | $0.20 |
| Coffee Maker (894 Watts) | one hour/day | 27 | $2.70 |
| Dishwasher (1,200 Watts) (excludes hot water costs) |
one hour/day | 37 | $3.70 |
| Microwave Oven (1,450 W) | 30 min./day | 22 | $2.20 |
| Range (12,200 Watts) | 30 min./day | 186 | $18.60 |
| Freezer 15 Cu. Ft. (341 W.) | 12 hrs/day | 124 | $12.40 |
| Refrigerator – 14 Cu. Ft. (440 W.) | 12 hrs/day | 161 | $16.10 |
| Refrigerator – 18 Cu. Ft. (manual defrost – deduct 35%) |
12 hrs/day | 180 | $18.00 |
| Laundry | |||
| Clothes Dryer (4,900 W) | 6 loads/week | 90 | $9.00 |
| Washer (512 Watts) (Excludes water costs) |
6 loads/week | 9 | $.90 |
| Home Entertainment/Recreation | |||
| 42″ Plasma TV (320 Watts) (instant-on tvs use some electricity continuously) |
35 hours/week | 44.8 | $4.48 |
| Home Computer (500 W) Including Monitor |
4 hours/day | 61 | $6.10 |
| Hot Tub (5,000 W) | 2 hrs/day | 304 | $30.40 |
| Pool Heater (incl. motor) | avg/daily | 670 | $67.00 |
| Pool Pump (1 hp) | continuous | 1240 | $124.00 |
| Lighting | |||
| 40-Watt Bulb (40 W) Equivalent compact fluorescent |
4 hours/day 4 hours/day |
5 1.375 |
$.50 $.14 |
| 60-Watt Bulb (60 W) Equivalent compact fluorescent |
4 hours/day 4 hours/day |
7 1.625 |
$.70 $.16 |
| 75-Watt Bulb (75 W) Equivalent compact fluorescent |
4 hours/day 4 hours/day |
9 2.5 |
$.90 $.25 |
| 100-Watt Bulb (100 W) Equivalent compact fluorescent |
4 hours/day 4 hours/day |
12 3.25 |
$1.20 $.33 |
| Farm | |||
| Electric Fence Charger | daily | 2 | $.20 |
| Heater (tractor engine block) (600W) | 10 hrs/day | 182 | $18.20 |
| Heater (livestock tank) | 8 hrs/daily | 365 | $36.50 |
| Auto Battery Charger (600W) | 2 hours | 36 | $3.60 |
| Well Pump (750-1000W) | avg./10% usage | 40 | $4.00 |
For other tips on saving energy visit the Department of Energy Web site, Energy Savers – Tips on Saving Energy and Money at Home
