SEER to EER Conversion Calculator

ANA›Life Services Authority›National Calculator Authority›SEER to EER Conversion Calculator

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SEER to EER Conversion Calculator

Convert SEER (Seasonal Energy Efficiency Ratio) to EER (Energy Efficiency Ratio) using the industry-standard formula developed by Carrier and widely adopted by AHRI (Air-Conditioning, Heating, and Refrigeration Institute).

SEER Rating

BTU/Wh

Outdoor Design Temperature (optional)

95°F — Standard ARI Condition (Default) 82°F — Mild Climate 100°F — Hot Climate

Calculate

EER:— COP (Coefficient of Performance):— Efficiency Category:— Formula Used:—

function seeCalc() { const resultBox = document.getElementById('see_result'); const errorBox = document.getElementById('see_error'); resultBox.style.display = 'none'; errorBox.style.display = 'none';

const seer = parseFloat(document.getElementById('see_seer').value); const outdoorTemp = parseFloat(document.getElementById('see_outdoor_temp').value);

// --- Input Validation --- if (isNaN(seer)) { errorBox.textContent = 'Please enter a valid SEER rating.'; errorBox.style.display = 'block'; return; } if (seer 50) { errorBox.textContent = 'SEER value seems unrealistically high (max ~50 for current technology). Please verify.'; errorBox.style.display = 'block'; return; }

// --- Core Formula --- // AHRI / Carrier formula: // EER = -0.02 * SEER^2 + 1.12 * SEER // Valid for standard ARI test condition (95°F outdoor, 80°F/67°F wb indoor). // Source: Carrier Engineering Reference; AHRI Standard 210/240. const eer_standard = (-0.02 * seer * seer) + (1.12 * seer);

// Temperature-adjusted EER (for non-95°F conditions): // EER_adj = EER_95 - 0.07 * (outdoor_temp - 95) // Source: DOE/ORNL adjustment factor used in Manual J load calculations. const eer_adjusted = eer_standard - 0.07 * (outdoorTemp - 95);

// COP = EER / 3.412 (1 W = 3.412 BTU/h) const cop = eer_adjusted / 3.412;

// --- Efficiency Category --- let category = ''; if (seer >= 25) category = '⭐ Ultra-High Efficiency (SEER 25+)'; else if (seer >= 20) category = '⭐ Very High Efficiency (SEER 20–24)'; else if (seer >= 16) category = '✅ High Efficiency (SEER 16–19) — ENERGY STAR Qualified'; else if (seer >= 14) category = '✅ Above Standard (SEER 14–15)'; else if (seer >= 13) category = '⚠️ Minimum Federal Standard (SEER 13–14, South/Southwest US)'; else category = '⚠️ Minimum Federal Standard (SEER 8–12, North US legacy)';

// --- Formula label --- let formulaUsed = 'EER = −0.02 × SEER² + 1.12 × SEER (ARI 95°F standard)'; if (outdoorTemp !== 95) { formulaUsed += '; then EER_adj = EER − 0.07 × (T_outdoor − 95)'; }

// --- Display Results --- document.getElementById('see_eer_out').textContent = eer_adjusted.toFixed(2) + ' BTU/Wh'; document.getElementById('see_cop_out').textContent = cop.toFixed(3); document.getElementById('see_category_out').textContent = category; document.getElementById('see_formula_used_out').textContent = formulaUsed;

resultBox.style.display = 'block'; }

#### Formulas

Step 1 — EER at Standard Condition (95°F outdoor):

EER = −0.02 × SEER² + 1.12 × SEER

This quadratic relationship was derived empirically by Carrier and is the industry-standard conversion adopted by AHRI (Air-Conditioning, Heating, and Refrigeration Institute) in Standard 210/240. It accounts for the fact that SEER is a seasonal average measured across a range of temperatures (65°F–104°F), while EER is a single-point rating at 95°F outdoor / 80°F dry-bulb / 67°F wet-bulb indoor.

Step 2 — Temperature Adjustment (optional, non-95°F designs):

EER_adjusted = EER − 0.07 × (T_outdoor − 95)

A linear correction factor of 0.07 BTU/Wh per °F deviation from 95°F, sourced from DOE/ORNL research and used in ACCA Manual J residential load calculations.

Step 3 — COP (Coefficient of Performance):

COP = EER ÷ 3.412

Conversion factor: 1 watt = 3.412 BTU/hour (exact thermodynamic constant).

#### Assumptions & References

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