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Free online carbon footprint calculator to estimate CO2 from driving, home energy, and travel. Discover ways to reduce your personal environmental impact.
Calculate electricity cost from watts, hours per day, and rate. Get daily and monthly cost. Appliance energy calculator.
Free online water usage calculator to estimate household gallons and monthly water bills by fixture and habit. Find easy ways to conserve water and save.
Calculates the annual cost of running any appliance based on wattage, daily active hours, and utility electric rates per kWh.
Annual Cost = (Wattage × Daily Hours ÷ 1,000) × 365 Days × Electric Rate per kWhCalculates the exact savings from replacing incandescent bulbs (e.g. 60W) with equivalent LED bulbs (e.g. 9W).
Annual LED Savings = Number of Bulbs × (Incandescent Watts - LED Watts) ÷ 1,000 × Daily Hours × 365 × RateDetermines the number of years needed for utility savings to pay off the initial purchase price of the new technology.
Payback Period (Years) = Purchase Price ÷ Annual Energy SavingsUpdated: July 2026
Replacing 30 old 60-watt incandescent bulbs with 30 9-watt LED bulbs, used 4 hours a day on average.
→ Annual energy savings: ~$357; If LED bulbs cost $90 total, payback is within 3 months
Replacing a 15-year-old inefficient refrigerator (using 1,200 kWh annually) with a modern Energy Star unit (using 400 kWh).
→ Annual energy savings: $160; Payback period: 5.6 years
Installing a smart thermostat to lower average annual heating/cooling energy costs ($1,200/year) by an estimated 12%.
→ Annual savings: $144; Payback period: 15 months
Upgrading to energy-efficient appliances, LED lighting, or smart thermostats can substantially lower your residential electric and gas bills. This calculator evaluates your energy savings and calculates the payback period of your investments.