The average American household spent $280 last year on cooling costs. Although this figure might seem deceptively low (costing you less than $25 per month annually). If you live in a much warmer climate zone, however, the key to keeping your AC costs reasonable is choosing the right AC unit for your home and your climate.
Outside Temperatures: the hotter it is where you live the bigger AC unit you'll need, right? That's a common misconception. Although outside temperatures are big factor, the biggest factor is often the average low. Whatever the average low temperature is for your area, the bigger the AC unit you're going to need. The reason why the low point is such a determining factor is that daily lows dictate the temperature cycle in your home. For instance, if you live in an area where the low is substantially lower than the high, you can rely on Mother Nature a little more to help cool your home at night. Conversely, if the low point is relatively close to the high, then you'll need a more powerful and efficient AC unit to cool your home.
Humidity: choosing the right AC for your home requires more than just looking at average temperatures. The other major factor is humidity. To correlate temperature and humidity conditions in your area, a good statistic to use is dew point. Simply put, the higher the average dew point in your area, the more powerful and efficient AC unit you'll need. One of the beautiful features of an AC unit is that it conditions the air in a space, making it cooler, drier, and much more comfortable than the air outside.
Units (by space)
The amount of space you'll need your AC to cool, the more powerful and efficient unit you'll need. You may, however, find that you don't need to cool your entire home and can buy a smaller unit.
Single Room: although window-mounted or portable AC units aren't as powerful or efficient as a central heating/cooling unit, they can be more cost effective. These small AC workhorses are particularly effective for cooling small, contained-spaces like bedrooms for short intervals. For instance, if you only really "need" an AC to make it comfortable while you sleep, a window-mounted unit is likely your best bet. These units work well in both arid and humid environments.
Swamp Cooler: a swamp coolers are ideal for humid conditions with a particularly high dew point. These AC units cool by evaporating water. Thus, the more humid the environment, the better. A big swamp cooler unit can be mounted in a central location and cool multiple rooms. Additionally, they are relatively inexpensive, easy to install, and energy efficient.
Central Unit: a central heating/cooling system is the most expensive and powerful option. If you live in a climate with a particularly high dew point, you should consider installing a central AC unit. These units pump cool air into every room. Thus, each room gets direct flow. For cooling large, multi-room spaces, you simply can't beat a central AC system.
AC system are classified by the kilowatts (kW) electricity need to power them per hour (kWh). Generally, the higher the kWh, the more powerful the system, but the more energy dependent they'll be.
- Central Systems: 3.0 kWh ($0.33 per hour)
- Window-Mounted & Portable: .73 – 1.8 kWh ($.08 - $0.20 per hour)
It's important to consider the long term cost of the system you invest your money in. Although central systems cost more up front and to operate, they also last much longer than other AC systems.
Discussing your AC options with your licensed plumbing professional is the key to help you solve your cooling needs. For more information, you could look here.