Heat Wave Continues – My Air Conditioner Never Quits!

For the past two weeks, temperatures here in South Central Kansas have been hot! It is August in Kansas, what are we supposed to expect? Yep! The red heat advisory notice on my Weatherbug App has been flashing every day!

Starting July 17th here are the daily highs at Mid-Continent Airport:

99 100 101 99 98 99 100 102 92 95 93 95 93 101 100

100 108 109 100 94 94 97 105 103 103

That said, I really am glad for my Air Conditioning! I grew up in Southern Nevada, the desert! You know, 115 degrees F and 20% humidity. August in Kansas is not like that! 103 today and 70% humidity. You must know, I’m really glad for my Air Conditioning! Oh, I said that before – can you tell, I am really glad for my AC. I have heard on FB and Twitter all week about others that are also glad for their AC. Especially when it is not working and you are waiting on the HVAC Tech to come service the AC! Cooking brownies, or cookies, or a large cold lemonade for the Technician – Go for it! Anything that helps get the AC going again.

How about a count of hands?

How many people have their AC units running 24/7? So, what does that mean? Your AC runs all the time! The unit does not start and stop. Which is better? Running more is better – here is why.

When your HVAC contractor plans your unit – they start with design temperatures. If you live in Maine your summer and winter design temperatures are different from Georgia or from Kansas. Caribou would use design temperatures of -18 and 81 ; Atlanta would use 18 and 92 ; Wichita would use 5 and 98 .

A design temperature will cover 97.5% of the daily highs or lows for summer and winter that occur in that area.

Since the Wichita summer design temperature is 98 degrees F; any day with a high temperature approaching or over that, is going to require your AC unit to run 24/7. It will be keeping up or trying to catch up, depending on other factors, such has household routines and the effectiveness of the energy saving features in the house.

But the AC unit is running all the time! Will it break down!

The mechanical design of many machines is to run at a constant speed. Think about your TV – it runs at the same speed, full volume or muted, the TV does the same thing, at the same speed. A chain saw is designed to run at a constant speed. The washer or dryer rotation is constant. The electric motors in these run at the same speed, the slower wash cycles actually gear the speed down using a belt and transmission; the motor is still running the same speed. And so is your AC. It is designed to do that.

Does it need a rest? No! It is a machine. Machines need periodic maintenance. Oil changes on your car are one example. If you have your AC unit serviced each Spring before it gets very warm, you can look forward to a trouble free summer.

What can you do to help now?

First, change your filter. That will allow the proper air to flow through your system. The proper air flow across your coil will result in more comfort in your house. The filter is attached to the furnace on the return air side. You can buy them at a local hardware or building supply store.

Second, Check the outside unit. Is anything blocking the air flow in and around the unit? High grass, weeds or flowers? Dead grass, trash, leaves or other stuff? You can pull that away.

If the outside looks clean what about the coils? Turn the AC off. There is usually a switch (fuse box or circuit breaker) near the unit. You turn the unit off, so the fan would not spray the water back in your face.

Use your garden hose to force water through the coils (the piece around the outside that looks like a car radiator). Spray from the inside out, because the fan pulls air (and dirt) from the outside in. Good job for early in the morning. Then turn the unit back on.

Oh! You are not that mechanically inclined! Don’t feel bad, many people are not, or do not have the time. So, call your HVAC Service Company and schedule them for a filter change and coil wash. Tell them specifically, they may have a specific employee to send out for those short jobs. Hire a handy man. Ask a handy neighbor. There are many ways to get that done.

What about a larger AC unit?

A unit larger than specified for your house will use more electricity, it may provide some additional initial cooling, depending on several factors. A unit larger than specified will not remove as much humidity. If the unit cools the air faster, it will shut off. A properly sized unit will run longer to cool and take the humidity out of the air, increasing your comfort. All this for a larger electric bill. Yesterday, 8-10, the Wichita high temp was 103 with a high relative humidity around 70. If your ac unit is oversized and the relative humidity is around 90%. You will have a cold, clammy, always wet feel to your house.

References on this topic and additional reading can be found on the federal Department of Energy website, the Air Conditioning Contractors of America (ACCA) website, and home performance contractors around the country. Sizing of AC units is done using ACCA Manual J calculations.

http://www.doe.gov for the Department of Energy
http://www.acca.com for the ACCA website
http://www.kcc.state.ks.us/energy/index.htm for the Kansas Energy Office

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