Home Energy Usage Estimator

How This Tool Works

This calculator estimates energy consumption and costs for individual appliances based on wattage and usage time. The formula is simple: Energy (kWh) = (Wattage × Hours) / 1000. One kilowatt-hour (kWh) is the energy used by a 1000-watt appliance running for one hour.

The calculator multiplies daily usage by 30 for monthly estimates and by 365 for yearly estimates. It then multiplies energy consumption by your electricity rate to calculate costs. This helps you identify which appliances are consuming the most energy and costing the most money, so you can make informed decisions about usage patterns and potential upgrades.

Common Appliance Wattages

• Refrigerator: 100-200W (runs intermittently, ~1-2 kWh/day)
• LED TV (55"): 50-100W
• Laptop: 50-100W
• Desktop Computer: 200-400W
• Microwave: 1000-1500W (only when running)
• Electric Oven: 2000-5000W
• Air Conditioner (window): 1000-2000W
• Central AC: 3000-5000W
• Clothes Dryer: 1800-5000W
• Space Heater: 1500W
• LED Light Bulb: 8-12W (vs. 60W incandescent)

Tips for Reducing Energy Costs

• Use Energy Star Appliances: Certified appliances use 10-50% less energy
• Unplug When Not in Use: Many devices draw "phantom" power even when off
• Switch to LED Bulbs: Use 75% less energy than incandescent bulbs
• Maintain Appliances: Clean filters, defrost freezers, service HVAC systems
• Use Power Strips: Easily turn off multiple devices at once
• Optimize Usage Times: Use high-wattage appliances during off-peak hours if available
• Replace Old Appliances: Newer models are significantly more efficient
• Monitor Usage: Use this calculator to identify energy hogs and adjust usage

FAQ

• How do I calculate energy usage for an appliance?
  Energy usage is calculated as: kWh = (Wattage × Hours) / 1000. For example, a 1500W appliance used 8 hours per day: (1500 × 8) / 1000 = 12 kWh per day. Multiply by 30 for monthly usage (360 kWh/month). Multiply by your electricity rate ($/kWh) to get cost. Most appliances have wattage listed on labels or in manuals.
• How much electricity does a refrigerator use?
  Refrigerators typically use 100-200 watts when running, but they cycle on and off. Average daily usage is about 1-2 kWh for energy-efficient models, or 30-60 kWh per month. Older models may use 2-3 times more. Always-on appliances like refrigerators should use 24 hours in the calculator, but actual runtime is less due to cycling.
• What appliances use the most electricity?
  High-wattage appliances that run frequently use the most electricity: Air conditioners (1000-5000W), Electric water heaters (3000-5500W), Electric ovens/ranges (2000-5000W), Clothes dryers (1800-5000W), Space heaters (1500W). Even if used less frequently, high wattage means high cost when running. Check wattage labels and usage patterns.
• How do I find my appliance wattage?
  Check the appliance label, manual, or Energy Guide label. Wattage is usually listed as "W" or "watts". If you only see amps (A) and volts (V), multiply them: Watts = Amps × Volts. For example, 10A × 120V = 1200W. Some appliances list maximum wattage - use that for worst-case estimates.
• What is the average electricity cost per kWh?
  Average US electricity cost is $0.12-0.15 per kWh, but varies by state and utility. Hawaii has the highest rates (~$0.30/kWh), while states like Washington and Louisiana have lower rates (~$0.10/kWh). Check your utility bill for your exact rate. Some utilities charge different rates for peak/off-peak hours.
• How can I reduce my energy costs?
  Ways to reduce energy costs: Use Energy Star certified appliances, unplug devices when not in use (phantom loads), use LED bulbs instead of incandescent, set thermostats efficiently, use appliances during off-peak hours if available, maintain appliances (clean filters, defrost freezers), replace old appliances with energy-efficient models, use power strips to easily turn off multiple devices.