Btu stands for British Thermal Unit. You’re bound to come across the term when looking for a new cooling system. It’s best known as a unit of measurement that describes the amount of AC needed to lower the temperature of 1 pound of liquid by 1 degree Fahrenheit.
Why Is the Number of BTUs so Important?
The number of Btus affects how well your AC runs. The higher the Btu number, the more cooling power the air conditioner has. Understanding Btus makes it possible for you to stay comfortable, even during the hottest weather.
What’s an EER?
We can measure a cooling system’s efficiency in terms of Energy Efficiency Ratio (EER). It’s the ratio between the cooling output of a complete air conditioner system and the input energy to power. To calculate an air conditioner’s EER, divide its Btu rating by its wattage.
These unit specs show you the cooling capabilities of your AC, and each power output setting is helpful, especially when figuring out how to cool your home efficiently. For example, if your air conditioner has a higher Btu rating than the room size needs, it will waste energy. Although it will cool the room quicker, it won’t be able to remove humidity as good as units with smaller ratings. It will also cost more to run and wear out faster due to using more electricity.
How to Choose the Right Size of Air Conditioner
Room air conditioners come in a wide variety of sizes. While this is good for you because it means you have a lot of choices, it also means that you need to know which size of air conditioner to buy. Remember, the Btu/hr rating of an air conditioner is the maximum amount of heat it can remove from a room in one hour. If calculated wrong, you can end up with a cooling system that uses up too much energy. Here’s an equation to avoid common mistakes when calculating the Btu rating for an AC system:
To find the best air conditioner size for your room, you first need to know your room’s area per square foot. You can calculate the square footage of a room by simply multiplying the length and the width (length x width = area). Next, you need to multiply the area by 20 Btus. This calculation is ideal since you need an air conditioner with a cooling capacity of at least 20 Btus per square foot of living space. Most Btu calculators use this very same equation to come up with the following chart:
- 100 to 150 square feet – 5,000 Btus per/hr
- 150 to 250 square feet – 6,000 Btus per/hr
- 250 to 300 square feet – 7,000 Btus per/hr
- 300 to 350 square feet – 8,000 Btus per/hr
- 350 to 400 square feet – 9,000 Btus per/hr
- 400 to 450 square feet – 10,000 Btus per/hr
- 450 to 550 square feet – 12,000 Btus per/hr
Also, 1 ton of cooling power is equal to 12,000 Btus. The average home needs 3 tons of cooling power on a hot day. That means it has to push out around 36,000 Btus of cool air per hour.
How Much Does It Cost to Run an AC?
The most popular air conditioner model in the U.S. comes with a 5,000-Btu rate. The average cost to run a 5-amp, 5,000-Btu AC is $1.60 a day ($0.06 per hour, or $0.001 per minute). That may not sound like much, but it can run your bill pretty high.
To find the bill cost, multiply the daily cost by the number of days in the month ($1.60 x 30 days). That gives you about $48. To get the yearly cost, multiply the monthly cost by the hottest months in the year. For many, the hottest months are June, July, and August ($48 x 3 months). This calculation will show that the average American pays about $144 on air conditioning annually. If you live in a state that’s warm year-round, you might end up paying between $288 and $576 a year. If your AC gives you a higher bill, have someone inspect it for leaks.
Contact a Professional
Clockwork Heating and Air Conditioning provides highly-trained home comfort experts that are ready to handle your every need no matter how big or small. Whether it’s installing new HVAC systems, maintenance, or repair, we’ve got you covered. We even provide budget solutions for residents of Athens, Georgia and nearby communities so you can feel good about your investment. Call us today to schedule an appointment.