Deodiaus wrote:
I had a problem with my AC units. I thought it was the freon which
was too low.
The AC guy came out and said that he first recommended cleaning the
outside AC units, at $80/unit. His partner says that my units look
clean. He says that they should be cleaned every year.
So he takes off the top casing, washes it with a lawn hose, sprays on
an A/C cleaner (sodium hydroxide based), and washes it off. $300
later, he says that the freon needs to be added too. Ok, another $150
later the problem is solved. I got the feeling I was hood winked and
robbed.
Two questions.
Is washing and cleaning the units standard practice? Is it even
necessary to do it once a year? On my old house, I haven't cleaned
them in 3 years and never noticed a higher than average bill for not
doing so.
How much efficiency is lost by not cleaning the units? The repair guy
quoted 50%, but I made a smart ass remark like 5%/yr.

We recommend cleaning the outdoor condensing unit once
a year for a straight AC and twice a year for a heat pump.
The evaporator coil, "the cold part inside" should be
checked at the same time and cleaned if necessary. If you
change your filters regularly, you should have no problems
with the evaporator. I always tell customers to turn the
AC off when you are cutting the grass because the dust and
grass clippings will be sucked into the fins clogging them
up. You should keep hedges and landscaping plants away
from the outdoor unit. A lot of folks will pile mulch and
bark around the AC unit and that's a bad idea too. I like
to see a bed of pea gravel or rocks around them and the
grass/weeds pulled from around the units. Air flow, air flow
should be the AC mantra especially in this hot weather.

TDD