this one is driving me nuts. i have a 200 sq ft room used as office and electronics workshop. using the 30 btu/sq ft guide, i've estimated the load to be ~8900 btu. (unshaded southwest corner, small windows, minimal insulation, east texas.) the additional 2900 btu is desktop computer, server, etc. for seven years i ran a 12,000 btu ge unit that while oversized i had no issues with it. late last season the fan bearings gave out and i decided to replace the unit. at that time the stock on store shelves was pretty thin, but i found a deep discounted samsung 12k. the first thing i noticed was the short cycling this unit does. it was the end of the season, so i ignored it.

here we are half way through summer and this thing is still ferociously short cycling. of course i only see this short cycling when i'm at home at night. during the heat of the day i'm not real sure how it behaves, other than my server is still running.

so i'm down to two options. (1) run the unit until it beats itself up short cycling and be certain to not make the same mistake again. (2) grab a new, smaller unit while there are still some available.

anyone willing to share their thoughts?

if the best plan is to replace it, then what is the guide for sizing error? a 10k btu unit is 10% too large and a 12k is 25% too large. i suppose 25% is beyond acceptable. but i certainly don't want to go too small. when the workbench is fired up, there can be as much as 1200 watts dissapated.

btw, the sensible loads (electronic) are measured power. the current draw of the samsung 12k unit is within 5% of rating plate.

thanks.