Bests & Worsts Reviews from Amazon

I've been having AC troubles in the top floor of my 3 story home, and a recent AC guy pointed out that my outside condenser unit coils were completely choked up with dirt/debris (new construction when I bought it 3 or 4 years ago, but never serviced since). He generously offered to clean it for $185, because it required "very expensive chemicals". About 15 seconds on Google suggested that I could do this myself - so 2 cans of this spray and a few minutes of my time and the coils that looked like solid fuzz/mud/gunk actually show metal again! WHAT I DID: 1. Turned the condenser/fan off at the breaker. Not sure if this was necessary, but I figured better safe than sorry. Of course this is an outside unit and exposed to rain, etc, but why chance anything? 2. Sprayed this on... the beam is narrow, so it'll take awhile. Given that my unit (for a 3 story, 2600ft townhouse) had 4 walls and complete wraparound coils, I would have liked to have 4 bottles of the stuff. I ran both of mine dry and would have liked either better coverage or a second pass. 3. Waited about 15-20 minutes. I could see the metal showing through (incredible), but it certainly wasn't sparkling clean by any means. 4. Combination dragging a toilet bowl cleaner brush along the fins (top to bottom, with the fins to avoid mending them over) while rinsing with a water hose. A BUNCH of sludge washed out, including fine dust that took awhile to run clear. This would suggest that the "leave on and walk away" method may not be the best for extremely dirty units (such as mine), if you have the choice of cleaning further. On an interior coil where water isn't an option, an air compressor to help clear the fins may be a solid choice as well. Anyway, this stuff works, and I'm about to add it to my permanent stock and yearly plan... will update once I see how much of an impact cleaning the coils had on the AC.