View Single Post
Old 02-22-20, 11:14 PM   #6
jeff5may
Supreme EcoRenovator
 
Join Date: Jan 2010
Location: elizabethtown, ky, USA
Posts: 2,428
Thanks: 431
Thanked 619 Times in 517 Posts
Send a message via Yahoo to jeff5may
Default

Any window unit you buy that has a standard rating is done with a 10 degree Delta T between indoor and outdoor dry bulb temperature on high speed.

So, your 5kbtu 9.8 EER happens when it's 75 inside and 85 outside on high speed. Plus or minus 1 EER is normal. Also, this only holds true after the outdoor fan starts slinging indoor moisture on the outdoor heat exchanger. Without the "swamp" cooling effect, performance is closer to that of a dehumidifier. So, on those swampy 100 degF days, your actual EER is lower, probably closer to 8.

However, on these "lower efficiency" days, the unit is actually moving more BTU than a cooler day. Since the condenser pressure is higher, the cap tubes flow more mass into the evaporator. Considering that the humidity is higher on hot days, the capacity increase will follow the humidity load.

Last edited by jeff5may; 02-23-20 at 12:09 PM..
jeff5may is offline   Reply With Quote