(Often corresponds to the tonnage of your unit, e.g., 36000 BTU/hr = 3 tons)
Understanding SEER and Energy Savings
The Seasonal Energy Efficiency Ratio (SEER) is a standard measurement used in North America to indicate the energy efficiency of air conditioning and refrigeration systems. A higher SEER rating means the unit is more efficient and uses less electricity to provide the same amount of cooling.
This calculator helps you estimate the potential annual energy savings you could achieve by upgrading from an older, less efficient HVAC unit to a newer one with a higher SEER rating.
How the Calculation Works:
The core of the calculation relies on understanding the relationship between SEER, cooling load, operating hours, and electricity cost. The formula to estimate annual energy consumption (in Watt-hours) for a given cooling load is:
The annual cost is then calculated by multiplying the energy consumption in kWh by the cost per kWh:
Annual Cost ($) = Energy Consumption (kWh) * Energy Cost per kWh ($)
Therefore, the annual cost formula is:
Annual Cost ($) = (Cooling Load (BTU/hr) * Cooling Hours * Energy Cost per kWh ($)) / (SEER * 1000)
The calculator determines the annual cost for both your current unit and the potential new unit, and then finds the difference to show your estimated annual savings.
Key Input Factors:
Current & New SEER Rating: The efficiency of your existing and potential new HVAC system.
Average Annual Cooling Hours: The approximate number of hours your air conditioner runs per year. This varies significantly by climate and thermostat settings.
Cost of Electricity per Kilowatt-Hour: Your local utility rate for electricity.
Cooling Load of Home (BTU/hr): The capacity of your HVAC system needed to cool your home. This is often related to the system's tonnage (1 ton = 12,000 BTU/hr).
Upgrading to a higher SEER unit can lead to substantial savings on your energy bills over the lifespan of the equipment, especially in warmer climates or for homes with high cooling demands. Consider this calculator a tool to help illustrate the potential financial benefits of investing in energy-efficient HVAC technology.
function calculateSavings() {
var currentSEER = parseFloat(document.getElementById("currentSEER").value);
var newSEER = parseFloat(document.getElementById("newSEER").value);
var coolingHours = parseFloat(document.getElementById("coolingHours").value);
var energyCostKWH = parseFloat(document.getElementById("energyCostKWH").value);
var coolingLoadBTU = parseFloat(document.getElementById("coolingLoadBTU").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = "; // Clear previous results
if (isNaN(currentSEER) || isNaN(newSEER) || isNaN(coolingHours) || isNaN(energyCostKWH) || isNaN(coolingLoadBTU)) {
resultDiv.innerHTML = "Please enter valid numbers for all fields.";
return;
}
if (currentSEER <= 0 || newSEER <= 0 || coolingHours <= 0 || energyCostKWH <= 0 || coolingLoadBTU <= 0) {
resultDiv.innerHTML = "All input values must be positive.";
return;
}
if (newSEER <= currentSEER) {
resultDiv.innerHTML = "New SEER rating must be higher than the current one to show savings.";
return;
}
// Calculate annual energy consumption for current unit (kWh)
var currentConsumptionKWH = (coolingLoadBTU * coolingHours) / (currentSEER * 1000);
// Calculate annual energy cost for current unit ($)
var currentAnnualCost = currentConsumptionKWH * energyCostKWH;
// Calculate annual energy consumption for new unit (kWh)
var newConsumptionKWH = (coolingLoadBTU * coolingHours) / (newSEER * 1000);
// Calculate annual energy cost for new unit ($)
var newAnnualCost = newConsumptionKWH * energyCostKWH;
// Calculate annual savings ($)
var annualSavings = currentAnnualCost – newAnnualCost;
if (annualSavings < 0) {
annualSavings = 0; // Should not happen with validation, but as a safeguard
}
resultDiv.innerHTML = "Estimated Annual Savings: $" + annualSavings.toFixed(2) +
"(Current Annual Cost: $" + currentAnnualCost.toFixed(2) +
" | New Unit Annual Cost: $" + newAnnualCost.toFixed(2) + ")";
}