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jeff5may · 04-17-17, 01:42 AM

For a rough estimation, add 3 to the EER rating to get the SEER rating for window units. EER is measured at static conditions (95 degF outdoor / 75 degF indoor or close to it) and is directly equivalent to COP. SEER is not directly related to COP at many moments in time, it's just an average value that is calculated to yield higher numbers out of units that don't perform as well when it gets above 95 degF outside.

The industry does this to confuse the general population. For example, a 9000 btu window unit will generally have an EER that is 3 less than the SEER of a mini-split that has the same performance. Believe it or not, that 3 points sells lots of people into a mini-split that costs twice or three times as much. To be fair, there are more aspects to consider than raw performance. Apples versus oranges and such.

Window units without capacity control aren't going to have heavenly efficiency numbers. Manufacturers aren't highly interested in cramming inverter compressors and electronic expansion valves into window units. They are more interested in reducing the size and weight of window units to reduce handling difficulty and raw production cost. The energy star standard of 10.2 to 11 (depending on capacity) is good enough for 99 percent of everyone, so the cheaper and quieter and lighter that units can be designed, the more they will be competitive in this low-cost sector. In other words, they are not cost effective to improve much.

A new number, CEER, is the new EER for digital control board having room a/c units. It includes the standby power loss (5115 hrs x 1.4W vs. 750 hrs active load W) in the rating. I don't imagine it would be significantly different from EER, but it is a new number to further confuse the innocent.

04-17-17, 01:42 AM	#4
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,428 Thanks: 431 Thanked 619 Times in 517 Posts	For a rough estimation, add 3 to the EER rating to get the SEER rating for window units. EER is measured at static conditions (95 degF outdoor / 75 degF indoor or close to it) and is directly equivalent to COP. SEER is not directly related to COP at many moments in time, it's just an average value that is calculated to yield higher numbers out of units that don't perform as well when it gets above 95 degF outside. The industry does this to confuse the general population. For example, a 9000 btu window unit will generally have an EER that is 3 less than the SEER of a mini-split that has the same performance. Believe it or not, that 3 points sells lots of people into a mini-split that costs twice or three times as much. To be fair, there are more aspects to consider than raw performance. Apples versus oranges and such. Window units without capacity control aren't going to have heavenly efficiency numbers. Manufacturers aren't highly interested in cramming inverter compressors and electronic expansion valves into window units. They are more interested in reducing the size and weight of window units to reduce handling difficulty and raw production cost. The energy star standard of 10.2 to 11 (depending on capacity) is good enough for 99 percent of everyone, so the cheaper and quieter and lighter that units can be designed, the more they will be competitive in this low-cost sector. In other words, they are not cost effective to improve much. A new number, CEER, is the new EER for digital control board having room a/c units. It includes the standby power loss (5115 hrs x 1.4W vs. 750 hrs active load W) in the rating. I don't imagine it would be significantly different from EER, but it is a new number to further confuse the innocent.