Running your Air Conditioner when its 100+ Degrees Outside

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AC Maintenance: Keeping Cool During 100+ Degree Days

Here in Houston we just set a record for a straight 15 days in a row with daytime temperatures reaching or exceeding 100 degrees Fahrenheit. Yes, it’s hot, and air conditioners are taxed to their performance limits to try to keep up with cool air demands. Here are some things you need to know about running your AC unit in these kinds of conditions.

Should Your AC Unit be Bigger? No!

Central air conditioning systems are designed to suit the size of your home and the amount of air it needs to cool or heat. The size of the specific AC unit, the condenser, is chosen to be efficient for 98% of the typical high temperatures in your area (climate). So for that 2% extreme, like we are having this summer, your AC system may actually be undersized. But this is by design. Otherwise, if you went with a larger system that had no trouble pumping the volumes of cool air needed during these extremely hot days, your system would be quite inefficient 98% of the time. And that’s really almost all the time – not a good thing.

The larger system costs more to install and it consumes more energy to run, all costing you more money. Because it pumps more air volume it cools the house much faster. You might think this was a good thing but instead, it means the system is running through off-and-on cycles at a much higher rate. The shorter cooling cycles mean it is not quite running long enough to be pulling humidity out of your home. Removing humidity is part of how an air conditioner works. The condensing coil condenses water out of the air and the heat exchange process during that activity is what creates the cooler air. Warmer air and moisture are then exited from your home. Dryer air, even when warmer, is more comfortable for the human body as it allows our internal air conditioning, and evaporation of sweat, to be more efficient. Not removing sufficient humidity from your home could also lead to mold problems.

These are some of the reasons an oversized AC system is just an all-around bad idea. But you can still make the system you have work for you in these 100+ degree conditions.

Juicing More Efficiency Out of Your AC System

To make it easier for your AC system to reliably pump out cool air when it’s over 100 degrees outside you need to give it some help. We previously wrote a huge list of tips for energy savings in relation to ac usage. Apply as many of those as you can to help your cooling system cope with this heat.

In a nutshell, it comes down to reducing heat gains in the home. Some of the basics are;

Adjust The Thermostat and Close Off Unused Rooms

  • Turn the thermostat up a couple of degrees and be happy with 76 to 78-degree temperatures indoors.
  • Close off unused rooms – close doors and vents – don’t cool what you don’t use.

Control Sunlight and Heat Sources

  • Shade your windows on the sunny side of the house.
  • Cook outdoors – enjoy the summer BBQ.
  • Don’t use the dry cycle on the dishwasher – leave the door open and let them air dry.
  • Avoid running the clothes dryer during the heat of the day

Anything you can do to keep the house cooler, even a little bit, means the AC does not need to be running as long for each cooling cycle. Read more tips here

AC Maintenance is KEY!

Your central air system should be getting a maintenance checkup at least once a year. Ideally, the AC unit should be checked before peak demand in the summer heat, to ensure it’s running at its best when you need it most. It will be running long and hard through these multiple 100+ degrees days and may even need a check-up later on after all that heavy use.

If you’ve not had your system serviced yet this year, call your ac contractor (in Houston and the area, that’s us) and get it done. But you might need to wait a while, we get very very busy in times like this (does everyone wait till the last minute? Seems they do).

At the very least, go check your filters. Fresh clean filters allow more cool air to flow unobstructed. If the filters are only a little bit dirty, put fresh ones in now for this extreme heat period. You can still reuse those slightly dirty filters if you wish later once the summer begins to die down.

How cool should my house be if it's 100° outside?
The majority of air conditioning units are designed to only cool the air about 20 degrees from the outside temperature. If the temperatures outside are approaching triple digits, you should set your thermostat at about 78°.

A higher setting helps to:

Reduce stress on your AC system. Avoid wasted energy costs. Anything you can do to avoid generating additional heat inside your home will also help your cooling system perform better in periods of extremely high temperatures. Read our list of tips here and contact us if you suspect you need service.

Can it be too hot for your home AC to work?
Your AC unit is designed to work for average temperatures that we experience in south Texas. In addition, most AC units are only intended to cool indoor temperatures about 15 to 20 degrees lower than outside temperatures.

When temperatures climb up to the upper-90s and higher, it may seem like it's too hot for your home AC to work. But that may be because the system isn't capable of lowering the indoor temperature to your usual setting.

Suppose, however, you notice leaks or ice on an outdoor unit, or your AC can't keep the indoor temperature within 15 degrees of the outdoor temperature. In cases like those, you may have an issue. If you suspect you have a problem with your AC unit, contact the Clear the Air team today.

What can I do to make my home AC unit run more efficiently when it’s hot?
Anything you can do to reduce heat in your house (other than continually lowering the thermostat) will help your AC unit run more efficiently in high temperatures. Heat reduction measures may include not running your clothes dryer during the day, keeping your blinds or window shades closed, and not using your oven.

Try to avoid setting the temperature lower than 20 degrees than the outdoor air temperature. Check out our tips to help you stay cool.

In addition, regular maintenance will help your system perform at its peak when hot weather hits. Schedule a maintenance visit by contacting us today!

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