Energy Savings Estimator
ANA›Life Services Authority›National Calculator Authority›Energy Savings Estimator
.calc-container { max-width: 640px; margin: 2rem 0; padding: 1.5rem; background: #fff; border: 1px solid #ddd; border-radius: 8px; box-shadow: 0 1px 3px rgba(0,0,0,0.06); font-family: system-ui, -apple-system, sans-serif; } .calc-container h3 { font-family: Georgia, serif; font-size: 1.15rem; color: #1a1a1a; margin-bottom: 1rem; padding-bottom: 0.5rem; border-bottom: 2px solid var(--ac, #3d5a80); } .calc-row { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 0.75rem; flex-wrap: wrap; } .calc-row label { min-width: 160px; font-size: 0.9rem; color: #333; font-weight: 500; } .calc-row input[type="number"], .calc-row select { flex: 1; min-width: 120px; max-width: 200px; padding: 0.5rem 0.6rem; border: 1px solid #ccc; border-radius: 4px; font-size: 0.9rem; font-family: system-ui, sans-serif; color: #1a1a1a; background: #fafaf8; } .calc-row input:focus, .calc-row select:focus { outline: none; border-color: var(--ac, #3d5a80); box-shadow: 0 0 0 2px rgba(26,74,138,0.12); } .calc-row .unit { font-size: 0.82rem; color: #888; min-width: 30px; } .calc-btn { display: inline-block; margin-top: 0.5rem; padding: 0.55rem 1.5rem; background: var(--ac, #3d5a80); color: #fff; border: none; border-radius: 4px; font-size: 0.9rem; font-weight: 600; cursor: pointer; font-family: system-ui, sans-serif; } .calc-btn:hover { opacity: 0.9; } .calc-result { margin-top: 1.25rem; padding: 1rem 1.25rem; background: #f0f6fc; border-left: 3px solid var(--ac, #3d5a80); border-radius: 0 6px 6px 0; display: none; } .calc-result.visible { display: block; } .calc-result-label { font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.06em; color: #666; margin-bottom: 0.25rem; } .calc-result-value { font-size: 1.6rem; font-weight: 700; color: var(--ac, #3d5a80); } .calc-result-detail { font-size: 0.85rem; color: #555; margin-top: 0.5rem; line-height: 1.5; } .calc-note { margin-top: 1rem; font-size: 0.8rem; color: #888; font-style: italic; } .calc-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 0.75rem; margin-top: 0.75rem; } .calc-grid-item { padding: 0.6rem 0.8rem; background: #f8f9fa; border-radius: 4px; border: 1px solid #eee; } .calc-grid-item .label { font-size: 0.75rem; color: #888; text-transform: uppercase; letter-spacing: 0.04em; } .calc-grid-item .value { font-size: 1.1rem; font-weight: 600; color: #1a1a1a; } @media (max-width: 720px) { .calc-row { flex-direction: column; align-items: flex-start; gap: 0.3rem; } .calc-row label { min-width: auto; } .calc-row input[type="number"], .calc-row select { max-width: 100%; width: 100%; } .calc-grid { grid-template-columns: 1fr; } } .calc-chart { margin: 1rem 0; text-align: center; } .calc-chart svg { max-width: 100%; height: auto; } .calc-chart-legend { display: flex; flex-wrap: wrap; justify-content: center; gap: 0.6rem 1.2rem; margin-top: 0.6rem; font-size: 0.8rem; color: #555; } .calc-chart-legend span { display: inline-flex; align-items: center; gap: 0.3rem; } .calc-chart-legend i { display: inline-block; width: 10px; height: 10px; border-radius: 2px; font-style: normal; } .calc-related { max-width: 640px; margin: 2rem 0 1rem; padding: 1.25rem 1.5rem; background: #f8f9fa; border: 1px solid #e8e8e8; border-radius: 8px; } .calc-related h3 { font-family: Georgia, serif; font-size: 1rem; color: #1a1a1a; margin: 0 0 0.75rem; padding-bottom: 0.4rem; border-bottom: 2px solid var(--ac, #3d5a80); } .calc-related-list { list-style: none; padding: 0; margin: 0 0 0.75rem; display: grid; grid-template-columns: 1fr 1fr; gap: 0.4rem 1.5rem; } .calc-related-list li a { font-size: 0.88rem; color: var(--ac, #3d5a80); text-decoration: none; } .calc-related-list li a:hover { text-decoration: underline; } .calc-browse-all { margin: 0.5rem 0 0; font-size: 0.9rem; font-weight: 600; } .calc-browse-all a { color: var(--ac, #3d5a80); text-decoration: none; } .calc-browse-all a:hover { text-decoration: underline; } @media (max-width: 720px) { .calc-related-list { grid-template-columns: 1fr; } }
Energy Savings Estimator
Estimate annual energy consumption, cost savings, and CO₂ reduction when upgrading to a more efficient appliance or system.
Current Device Power Draw (Watts)
New/Efficient Device Power Draw (Watts)
Daily Usage Hours (hours/day)
Days Used Per Year (days/year)
Electricity Rate ($/kWh)
Calculate Savings
function eneCalc() { var resultDiv = document.getElementById('ene-result');
var powerOld = parseFloat(document.getElementById('ene-power-old').value); var powerNew = parseFloat(document.getElementById('ene-power-new').value); var hours = parseFloat(document.getElementById('ene-hours').value); var days = parseFloat(document.getElementById('ene-days').value); var rate = parseFloat(document.getElementById('ene-rate').value);
// --- Validation --- var errors = []; if (isNaN(powerOld) || powerOld = powerOld) errors.push("New device power must be less than current device power to show savings."); if (isNaN(hours) || hours 24) errors.push("Daily usage hours must be between 0 and 24."); if (isNaN(days) || days 365) errors.push("Days per year must be between 1 and 365."); if (isNaN(rate) || rate 0) { resultDiv.style.display = 'block'; resultDiv.innerHTML = '' + errors.join('') + ''; return; }
// --- Core Formulas --- // Annual energy consumption (kWh) = Power (W) × Hours/day × Days/year ÷ 1000 var energyOld = (powerOld * hours * days) / 1000; // kWh/year var energyNew = (powerNew * hours * days) / 1000; // kWh/year var energySaved = energyOld - energyNew; // kWh/year
// Annual cost savings ($) = Energy saved (kWh) × Rate ($/kWh) var costOld = energyOld * rate; var costNew = energyNew * rate; var costSaved = energySaved * rate;
// Efficiency improvement (%) var effImprovement = ((powerOld - powerNew) / powerOld) * 100;
// CO₂ reduction (kg/year) // US EPA average grid emission factor: 0.386 kg CO₂ per kWh (2023) var co2Factor = 0.386; var co2Reduced = energySaved * co2Factor;
// Payback period placeholder — not calculated (no cost input), shown as note // 5-year and 10-year projections var savings5yr = costSaved * 5; var savings10yr = costSaved * 10;
resultDiv.style.display = 'block'; resultDiv.innerHTML = '### Results ' + '' + 'Metric' + 'Current' + 'New/Efficient' + 'Savings' + 'Annual Energy Use' + '' + energyOld.toFixed(1) + ' kWh' + '' + energyNew.toFixed(1) + ' kWh' + '' + energySaved.toFixed(1) + ' kWh' + 'Annual Energy Cost' + '$' + costOld.toFixed(2) + '' + '$' + costNew.toFixed(2) + '' + '$' + costSaved.toFixed(2) + '' + 'CO₂ Emissions' + '' + (energyOld * co2Factor).toFixed(1) + ' kg' + '' + (energyNew * co2Factor).toFixed(1) + ' kg' + '' + co2Reduced.toFixed(1) + ' kg' + '' + '' + 'Efficiency Improvement: ' + effImprovement.toFixed(1) + '%' + '5-Year Cost Savings: $' + savings5yr.toFixed(2) + '' + '10-Year Cost Savings: $' + savings10yr.toFixed(2) + ''; }
#### Formulas Used
Annual Energy (kWh/yr) E = P × H × D ÷ 1,000 P = power draw (W), H = daily hours, D = days/year
Annual Cost ($) Cost = E × Rate
Annual Savings ΔE = Eold − Enew | ΔCost = ΔE × Rate
CO₂ Reduction (kg/yr) CO₂ = ΔE × 0.386 kg/kWh
Efficiency Improvement (%) η = (Pold − Pnew) ÷ Pold × 100
#### Assumptions & References
- CO₂ emission factor of 0.386 kg CO₂/kWh is the U.S. EPA national average grid emissions factor (EPA eGRID 2023).
- Formula reference: ENERGY STAR® Energy Savings Calculator Methodology, U.S. DOE.
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