Summer has arrived and you’ve probably already used your air conditioner. But how do you know it’s working at maximum efficiency?
Unfortunately, it’s not easy to tell if your AC is running at full spec. Even many professionals have difficulty squeezing out every last percent of efficiency, but you can certainly figure out whether there are big problems with your system.
- Start with the easy stuff and replace the air filter(s) if they’re not really clean. The more restriction to the air flow, the less efficiently the system will operate.
- Make sure you have an air tight cover on your filter port if the filter is one of the types that slide into your air handler’s housing. Why? If your air handler is in the attic and you leave that open, you can be losing 30% or more of your efficiency because of all the hot air that it sucks in through that opening.
Evaluating your cooling system performance
- Measure the air speed and temperature at each of the vents, placing the unit right on the air register. The main thing is to be consistent in placement. Let it measure until the temperature stabilizes.
- Also measure the air temperature going into your system. If you have a central air return, this is easy. You just need a general measurement of temperature. Usually this will be around 75F.
- For each air output, with a typical system, you should measure the temperature of the cool air at about 20 degrees cooler than the air going into the system. That’s called the “temperature drop.” This number varies a fair amount, but if it’s less than 15F or greater than 25F, you probably have a problem with the system.
- Get a feel for the amount of air coming out of each of the register. It should be a pretty good flow. If you find any that are much less flow than others, make a note of that. That could mean that a duct is detached or it might be shut off with a damper.
- It’s also a good idea to note any rooms that don’t seem to be getting cool. There are a number of things that could cause this – insufficient cold air flow, poor insulation, solar heating through windows, hot air leaking into the room and so on. Try to determine the cause and make a note of this. For example, if the room isn’t on the sunny side of the house and the cool air flow seems good, you’ve probably have bad insulation or a big leak of hot air from the attic.