My work in electronics has shown me that even imperceptible amounts of dust cause major strains on equipment.
The fan is the biggest load, and as it gets older and dustier the load increases.
“The fan is the biggest load, and as it gets older and dustier the load increases.”
Absolutely, especially during spin up.
That is true. AC heat exchangers can become dirty with the huge amount of air flowing through them. We've got a whole-house AC system and the fins can get bent, corroded and dirty over the years leading to reduced heat transfer efficiency which lowers AC efficiency.
I've used a commercial cleaner on our AC. You just spray it on and wash it off. You can get a "comb" to straighten any bent fins, too. I'm not sure how you would do this on a window unit, though.
Home Depot Purafilter 2000 coil cleaner.
The fan is not the biggest draw, rather it is the compressor that does the biggest work.