In the heat of the summer, it’s easy to assume that bigger is better when it comes to air conditioning (AC) systems. Obviously, if you have an air conditioner that’s too small in your Southern Nevada home, you will not be able to keep your temperatures consistently low even if the unit is running constantly. It’s important to know how to properly size an AC System to fit your home’s needs.
However, if your air conditioner is too large for your home, it will quickly cool down the space and shut off. Once the temperature rises, it will kick back on again. This constant on and off cycling, referred to as short cycling, uses a great deal of energy and wears down your air conditioning system more quickly.
Air conditioner loads must be calculated carefully, so you can match the unit to your cooling needs. Our professionals at JMAC Plumbing and Air Conditioning would be happy to help you select the best-sized air conditioner for your particular Nevada home. In the meantime, here is a peak into how our trained experts calculate air conditioning needs.
Definition of Terms
In order to understand how to size an air conditioning unit, you have to know a little bit about how capacity is measured. Air conditioning systems are measured by tons, which specifies how much a particular unit can cool. For example, a one-ton air conditioner can generate 12,000 BTUs.
A BTU is a British Thermal Unit, and one BTU is the energy needed to cool one pound of water by 1 degree Fahrenheit every hour.
Air Conditioner Sizes
The smallest air conditioner is 1.5 tons or 18,000 BTUs and they can increase in size up to 5 tons or 60,000 BTUs by increments of one-half ton or 6,000 BTUs.
For a rough calculation to select an air conditioner for your home, take your total square footage, multiply it by 25, divide it by 12,000, and subtract .5.
Of course, our JMAC Plumbing and Air Conditioning HVAC professionals use the complex Manual J load calculation to properly size HVAC systems. This rough calculation is only a ballpark figure, and shouldn’t be used on its own. There are other important elements that factor into the calculations.
Other Important Factors
Before ordering a new AC, you should take into account other factors to be considered before making a decision:
- Ceiling height. If you have a vaulted ceiling or open floor plan, you should calculate the volume of your home, not only the square footage. High ceilings will require a larger air conditioner.
- House style. Two homes that have the same square footage may require different-sized air conditioning systems. A single-story sprawling ranch home requires more cooling power than a three-story townhouse.
- Local climate. Temperature and humidity play a significant role in how much cooling and dehumidifying you need from your air conditioner.
- Size, type, and number of windows. Windows tend to leak energy out of your home more easily than solid walls. The size and number of windows are important factors to consider. Also, the windows’ energy rating will have an impact.
- Insulation. In a similar way, a better insulated home requires less cooling energy than a poorly insulated one.
- Other factors. Also consider the existing ductwork, type of window coverings, and number of residents and their schedules. These each can affect the load requirements of your system.