In the southeast part of the U.S., air conditioning is an important part of life. I’ve spent a few summers in the desert and I refuse to subject myself to that discomfort if I have a choice. I understand that air conditioning is a touchy subject to some – my father in-law has certain times during the day that correspond to certain settings on his thermostat. He will never divulge the proprietary algorithm that dictates the comfort of his home, and I don’t care because I have my own! Either way – we both like to keep our house cool.
But seriously, everyone has their own comfort level and there are so many variables that go into the energy efficiency of your home – I’m not going to dive deep into the details. I do want to paint a picture for you though as to what is happening when your A/C is running.
The Basics
In the United States, your typical air conditioner is rated by cooling tons. These are not your typical U.S. Tons, you know 2000 pounds to a ton – no. These are specifically COOLING TONS. 1 ton of cooling is equal to 12,000 BTUs (British Thermal Units) per HOUR.
British Thermal Units
And what is a BTU you ask? This is an important unit when describing how to keep your house cool. A BTU is the amount of heat required to raise the temperature of 1 pound of water by 1 degree Fahrenheit. We can keep going down the rabbit hole but just know this is a measure of how much heat can be transferred via the refrigeration (vapor) cycle from the inside of you house to the outside environment. The A/C professionals size the units depending on your region, size of your home, number of windows and doors, height of ceiling, and some other stuff.
Refrigeration Cycle
SEER Calculation
Every air conditioning unit also has an energy rating – SEER is the Seasonal Energy Efficiency Rating. This is the ratio of the cooling output in BTU to the energy input in watts. Local governments usually specify a minimum SEER that can be installed when buying new units. The higher the SEER rating, the more cooling you’re getting for your money. The SEER rating is essentially comfort divided by money!
Don’t Waste Money
The sun radiates the earth’s surface with about 1.3 kilowatts per square meter – the same heat that you are actively removing from your home with your A/C. While it seems the A/C is doing all of the work, there are a few things you can do to ensure that you are not throwing your hard-earned money out the window.
Seal Windows
Even if your windows are older and not the most efficient, there are some things you can do to help. Look to see the condition of the caulking around the window. Many times, the think strip of caulk is the only thing keeping that hot air from coming inside. If it is yellowed or cracked you should scrape it out and replace it. Yes, this is something that YOU can do! No need hire someone – a tube of caulk and a caulk gun will cost you about $10 at a hardware store. Another really simple way to keep heat from entering your house through the windows is to upgrade your window covers. Heavy curtains, black out shades, or wood / faux wood blinds do a great job of keeping the heat out and ensuring that your A/C isn’t working too hard.
Seal Doors
As you might expect, your doors are another weak spot in your house when it comes to energy efficiency. Look for cracks between the door and the door frame. If you can see daylight shining through, it’s time to replace the weather strip! You can pick up replacement weather strip at your local hardware store for less than $20 per door. The old stuff pulls right out and the new slides right in (you may need to cut to length with scissors). If you want to step up your door game even more, install storm doors. Storm doors add another level of insulation as well as give you the option to allow some of that sunlight in during the cooler months.
Attic Insulation
Check the condition of your attic insulation. This is something that many people overlook because, well, it’s in the attic. Many homes have blown in insulation – it can either be itchy fiberglass or more commonly now, shreds of organic material known as cellulose. Over time, this insulation compresses under its own weight and its effectiveness, or “R” value, decreases. Take a look at your local building code and see how many inches of insulation there should be in your attic. If it has compressed, or is missing in some areas, you have some options.
Hiring a contractor to come out and upgrade your insulation is probably the easiest way to handle this. Contractors that specialize in this have all of the equipment on hand and can have the job done in no time. I personally recommend this as blown in insulation can make a mess. Your other option is to rent the equipment and blow the insulation in yourself. Some people prefer to do this themselves – whether it be because of cost or they simply like working in their hot attic. Either way, get some estimates and choose your path to energy efficiency! This is a great way to keep your house cool.
Replace Filters
Replace your filters and get have your equipment serviced regularly. Normally there are filters inside your home that filter out dust and particulates before it is passed through the evaporator coils. Not replacing the filters regularly will cause the evaporator coils to collect dirt, reducing it’s heat exchanging efficiency. Furthermore, a dirty filter reduces airflow, again effecting it’s efficiency. As far as servicing the A/C unit, everyone has different views on this. I know people who have never had someone out to look at their HVAC system – only when it breaks! That should tell you something. I had a someone come out this spring, they washed the condenser coils, checked the capacitor and the refrigerant charge – gave me a piece of mind that the unit won’t break down this summer.
Run Fans to Feel Cool
This last item may not be for everyone but it can help you FEEL cooler when the summer heat is relentless. The thing is, a fan does not technically keep your house cool.
Turn fans on in the room you’re sitting in – the increased airflow will help your body to cool faster through convention and evaporation! This isn’t making your A/C run more efficient, but it may allow you to give it a break once in a while. Just remember to turn the fans off when you leave the room, they are not cooling your house off.
Reduce Cooling Costs
The average 3-ton air conditioner in the U.S. can cost upwards of $100 per month to run – this cost will vary depending on how much you pay for electricity, how cool you keep your house, how energy efficient it is, and even what region you live. But just using $100 per month as an example, that’s a lot of money! Take some of these tips and make sure that you’re getting the most comfort for your money!