Just change the filter!

As an old air conditioning man, I know the importance of having a clean filter for the air to go through on the way to the cooling coil. That was one of the first things I learned in my training. So, why would I not do that? Why would I not make sure I had a clean filter on my A/C unit? Filters don't cost much. They are no trouble to replace. So, why?

Last night I decided on the way to bed to check the filter on my upstairs unit. After removing one screw on the outside panel, I was ready to pull the filter for a look see. I did. It was so dirty! If you cannot see through it, it is dirty. Believe me. Hard to imagine any air getting through it to the cooling coil. Probably explains why it was taking so long to cool down the bedroom. I changed the filter. Just happened to have a spare, clean one on the ready, right inside the air handler door. I am lucky. This error on my part could have led to big time problems. Let me explain - for my own benefit.

I have already said what a filter is for. But let's go further. An A/C system is designed to operate most efficiently with a proper amount of cold refrigerant circulating inside the cooling coil tubing with a proper amount of outside ambient air flowing over the coil at a predetermined flow rate. Change the air flow, and the system is out of kilter. Too little air and the refrigerant does not evaporate to a gas and it goes back to the compressor, where it is liable to blow valves, leading to a compressor failure. Does that make sense?

The other thing is if the unit is not operating efficiently, the electric bill soars, and that cost money. Real dollars.

Not only that, but with low air flow because of a dirty filter the temperature of the refrigerant drops so low that it causes the coil to freeze up to a block of ice, rendering any air flow impossible. BTW, refrigerant temperature in the coil is usually about 35 deg. F., just to give you an idea of what I am talking about.

The thermostat set point, say 75 to 78 deg. is a good point, keeping the coil temp just right, and, with a clean filter, the proper amount of cool air going into the living space at about 60 to 65 degrees. That all keeps the house cool.

The filter is a prime component for all to work right. Sure, there are other things that can go wrong, but the filter is probably the number one reason for high electric bills and failed equipment. Imagine that. (I ought to know.)

My advice to all who might read this is this: keep the filter clean. Change it at least monthly. Don't do what I did.

This is just a maintenance reminder, a really important one.