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Energy Efficiency Ratio - EER

`"EER" = Q_l/W`
`(Q_l)"Energy Extracted"`
`(W) "Power Uptake"`
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The Energy Efficiency Ratio (EER) calculator is used to compute the EER rating of an energy system. Typically an A/C unit of some sort. It is calculated using the net cooling capcity in Btu/h and power in watts.

The efficiency is determined at a single rated condition specified by an appropriate equipment standard and is defined as the ratio of net cooling capacity - or heat removed in Btu/h - to the total input rate of electric power applied - in Watts. The units of EER are (Btu/h)/W.

EER = `Q_l/W`

where

  • EER = energy efficient ratio (Btu/h)/W - You won't usually see these units on a commercially packaged A/C box. They tend to just list the number without the units.
  • `Q_l` = net cooling capacity (Btu/h)
  • `W` = applied electrical power (Watts)

This efficiency term typically includes the energy requirement of auxiliary systems such as the indoor and outdoor fans. A higher EER means you have a more efficient system!