# EER ↔ SEER ↔ COP Converter (Refrigeration Efficiency) Convert between the three common refrigeration efficiency metrics: COP (dimensionless, W/W), EER (Btu/(W·h)), and SEER (seasonal Btu/(W·h)). Standard relations: COP = EER / 3.412, EER = COP × 3.412, SEER = EER / α (α seasonal weighting factor, default 0.875, adjustable 0.8–0.91 to match regional standards such as ARI 210/240). Enter any one metric and all three are reported. > Canonical page: https://elysiatools.com/en/tools/eer-seer-converter - **Category:** Math & Numbers - **Keywords:** EER, SEER, COP, energy efficiency ratio, seasonal energy efficiency ratio, coefficient of performance, refrigeration efficiency, HVAC, conversion ## Overview Convert between COP, EER, and SEER refrigeration efficiency metrics from a single numeric input. The converter reports all three values using COP = EER / 3.412 and SEER = EER / α, with an adjustable seasonal factor α. ## Inputs - **Input Metric** (select): Which metric the Input Value represents. The other two are computed from it. - **Input Value** (number): Value of the selected Input Metric. - **SEER↔EER Factor α** (number): Seasonal weighting factor α relating SEER and EER (SEER = EER/α). Default 0.875 (common US approximation). Adjust to match regional standards (0.8–0.91). - **Decimal Places** (number) ## When to use - Compare refrigeration or HVAC efficiency ratings expressed as COP, EER, or SEER. - Translate a manufacturer’s efficiency value into the metric required for calculations or reporting. - Check how different seasonal weighting factors affect the relationship between EER and SEER. ## How it works - Select whether the input value is COP, EER, or SEER. - Enter a non-negative numeric efficiency value. - Use the default SEER-to-EER factor of 0.875 or enter a value from 0.8 to 0.91. - The tool calculates and reports COP, EER, and SEER with the selected number of decimal places. ## Use cases - HVAC equipment comparison using consistent efficiency metrics. - Engineering and energy calculations that require COP, EER, or SEER values. - Regional or standards-based analysis using a customized seasonal weighting factor. ## Frequently asked questions ### Which efficiency metrics does this converter support? It converts between COP, EER, and SEER. ### What is the default SEER-to-EER factor? The default seasonal factor α is 0.875. ### Can I change the seasonal factor? Yes. You can set α between 0.8 and 0.91. ### What formula converts EER to COP? COP is calculated as EER divided by 3.412. ### How many decimal places can the result use? You can choose from 0 to 8 decimal places. ## Related tools - [Air Changes per Hour (ACH, n = Q/V)](https://elysiatools.com/en/tools/air-changes-per-hour): Compute the air change rate (ACH / n) of a room from the outdoor supply airflow Q and the room volume V: n = Q/V (1/h). Three modes: solve ACH (given Q and V), solve airflow (given n and V), or solve volume (given n and Q). Flow in m³/s/m³/h/CFM, volume in m³/ft³/L. 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