You hear a lot about “tonnage” and “SEER” when it comes to air conditioning. And, if you’re in the market for a new air conditioner, you’ll want to know what they mean.
Both these terms tell you a lot about how powerful the air conditioning is. In that way, they help you choose the unit that’s right for you. And, they may also save you some money.
Here’s a look at these terms: what they mean and how you can use them to choose your new HVAC equipment.
Tonnage measures the heat an air conditioner can remove from an area in sixty minutes. The term is based on the word “ton,” but doesn’t refer at all to the weight or mass of the ac unit. Instead, each “ton” can remove 12,000 British Thermal Units, or Btu’s, each hour.
Btu’s are measures of heat. It tells you the amount of heat that’s needed to raise the temperature of a pound of water by one degree Fahrenheit.
This information is especially important when you’re choosing a new central air system. You’ll want your new system’s tonnage to match the square footage of your home. If it’s too little, the system won’t do the job properly. Too much and you’re wasting money on extra power.
Usually, a house needs one ton of air conditioning for every 400 to 1,000 square feet. Of course, that’s a wide range. However, there are plenty of factors that affect the calculation. These include how many windows are in your home, how high the ceilings are an if air flows freely through the house or not.
The term SEER is short for “Seasonal Energy Efficiency Ratio.” It tells you how much energy the air conditioner uses every year. For central air units, the ratings range from the 13 to 25. The lower the rating, the more energy they use.
The measurable factors here are But’s and Kilowatt hours, or kWh. To calculate the rating, combine the heat the system removes with how much energy it takes to do so.
In this case, the energy is electricity. That’s what powers the air conditioning system. Power companies measure electricity usage by kHw. For the rating, you start with the Btu’s a unit can remove over an entire cooling season. Then you divide that by the number of kWh it would use to do it.
That formula provides you a measure of how well the ac works. Just remember, however, that this only offers a general guideline. There are a lot of other factors that this formula can’t account for.
One other factor is extreme heat. If the summers in your area are very hot, your ac will need to work harder to keep your home cool. The formula also doesn't work precisely if your electricity costs more than the national average.
Despite these variations, the rating is still useful. You can use it as a general guideline when choosing a unit. And, you can compare units against each other based on their ratings.
You can use the SEER rating to get an estimate of how much your electricity an ac will use. A high rating means it uses less energy than ones with lower ratings. And, using less power translates into lower monthly utility bills.
So, you’ll want to look for a higher rating if you’re looking to lower your bills. And, there’s also an upfront advantage: You may be able to get a rebate for choosing a high-efficiency model.
Today, all central air units have a rating of at least 13. Before 2008, they went as low as six. But, that year the U.S. Department of Energy mandated that all new central air units have a 13 rating or higher.
Then, the Environmental Protection Agency enacted the Energy Star program. This program identifies high-efficiency appliances and labels them as Energy Star Certified. That includes HVAC units.
For an Energy Star certification, an appliance must use less energy to do the same job as a comparable unit. For ac’s, that means a rating of 14.5 or higher.
Note, however, that this does not apply to portable, mounted or window units. Usually, they have ratings of around 10. So, none are nearly as efficient as central. So, while they have lower price tags, they cost much more in the long run.
Meanwhile, that higher rating can save you money. Energy companies across the country today encourage people to buy energy-efficient hvac equipment. And, they do so with cash.
If you’re getting ready to invest in any new heating or cooling appliances, check first with your local energy providers. The may offer rebates for installing Energy Star-certified equipment. With a little research, you can save anywhere from a few hundred to a few thousand dollars.
Are you looking for a new central air conditioning unit? Contact us, and we’ll help you choose the right system for your home and budget.