This calculator helps you estimate the annual electricity consumption and associated costs of a specific appliance. Understanding your energy usage is the first step towards managing your electricity bills and reducing your carbon footprint. By inputting the appliance's wattage, how often and for how long it's used, and your local electricity rate, you can gain valuable insights into your energy consumption patterns.
How it Works: The Calculation
The calculation involves several steps to convert the appliance's power consumption (in Watts) into a total energy consumed over a year (in Kilowatt-hours, kWh), and then to an estimated cost.
1. Total Hours Used Per Year: (Hours Used Per Day) * (Days Used Per Week) * (Weeks Used Per Year)
2. Total Watt-Hours Per Year: (Appliance Wattage) * (Total Hours Used Per Year)
3. Total Kilowatt-Hours (kWh) Per Year: (Total Watt-Hours Per Year) / 1000
We divide by 1000 because there are 1000 Watts in 1 Kilowatt.
4. Estimated Annual Cost: (Total Kilowatt-Hours Per Year) * (Cost Per Kilowatt-Hour)
Why Track Electricity Usage?
Cost Savings: Identify high-consumption appliances and explore ways to reduce usage or upgrade to more energy-efficient models.
Environmental Impact: Lowering electricity consumption reduces demand on power plants, many of which rely on fossil fuels, thus decreasing greenhouse gas emissions.
Appliance Efficiency: Compare the running costs of different appliances to make informed purchasing decisions.
Budgeting: Better predict and manage your monthly and annual electricity expenses.
Tips for Reducing Electricity Usage:
Unplug electronics when not in use (or use smart power strips).
Switch to LED lighting.
Ensure appliances are energy-efficient (look for ENERGY STAR ratings).
Optimize thermostat settings for heating and cooling.
Use appliances like washing machines and dishwashers with full loads.
By using this calculator regularly and implementing energy-saving practices, you can take control of your electricity consumption and contribute to a more sustainable future.
function calculateUsage() {
var wattage = parseFloat(document.getElementById("wattage").value);
var hoursPerDay = parseFloat(document.getElementById("hoursPerDay").value);
var daysPerWeek = parseFloat(document.getElementById("daysPerWeek").value);
var weeksPerYear = parseFloat(document.getElementById("weeksPerYear").value);
var costPerKwh = parseFloat(document.getElementById("costPerKwh").value);
var applianceName = document.getElementById("applianceName").value || "Appliance";
var resultValueElement = document.getElementById("result-value");
var resultDetailsElement = document.getElementById("result-details");
// Clear previous results
resultValueElement.innerText = "–";
resultDetailsElement.innerText = "";
// Input validation
if (isNaN(wattage) || wattage <= 0 ||
isNaN(hoursPerDay) || hoursPerDay < 0 ||
isNaN(daysPerWeek) || daysPerWeek 7 ||
isNaN(weeksPerYear) || weeksPerYear 52 ||
isNaN(costPerKwh) || costPerKwh < 0) {
resultDetailsElement.innerText = "Please enter valid positive numbers for all fields.";
return;
}
// Calculations
var totalHoursPerYear = hoursPerDay * daysPerWeek * weeksPerYear;
var totalWattHoursPerYear = wattage * totalHoursPerYear;
var totalKwhPerYear = totalWattHoursPerYear / 1000;
var annualCost = totalKwhPerYear * costPerKwh;
// Display results
resultValueElement.innerText = "$" + annualCost.toFixed(2);
resultDetailsElement.innerText =
"Estimated annual consumption for " + applianceName + ": " +
totalKwhPerYear.toFixed(2) + " kWh.";
}