4 Problems Caused by an Improperly Sized HVAC System

When you buy a new HVAC system for your Oak Ridge, Tennessee, home, the installer will need to determine what the best size should be. Size certainly matters when it comes to HVAC systems, and not necessarily the way you may expect it to. In fact, an HVAC system that is too powerful or large can waste money, comfort, and energy. The contractor must calculate how much heating or cooling capacity is needed to keep your home comfortable. This is called the load of the home.

The load of the home depends on a variety of factors. These include the building materials, which direction the house faces, the size, the number of household occupants, location of the rooms, the type of doors and windows and their thermal efficiency, the climate, ceiling height, and the list goes on. Calculating the load is vital for you to buy the correctly sized HVAC system. Why is this so important? Let us consider four problems that an improperly sized HVAC system can cause.

Too Much Power

If your HVAC system is too large for your home, it will have too much power. Because an overly large system cools quickly, once it reaches its programed-temperature, the thermostat shuts the program down before it has run its full cycle and cooled your whole home. This process is called short-cycling. An air conditioner is designed to put out a certain amount of cool air over a pre-determined time, but when it short-cycles it increases wear and tear on the system. This results in less efficiency and a greater chance of it breaking down than a correctly sized unit. Multiple repairs during the summer can put a serious burden on your household budget. It can also mean many hours without air conditioning. Besides the maintenance issues, short cycling also leads to indoor air quality issues.

Lack of Comfort

An oversized unit will cause wider temperature swings, especially in perimeter rooms. Indoor humidity plays an important role in feeling comfortable. Each time your air conditioner is turned on, the indoor coil takes about 10 to 15 minutes to get cold enough to condense the water vapor. Short-cycling means that your air conditioner will spend more time in this initial stage of "dry coil," which means it will remove less moisture than desired. When an oversized air conditioner is in cooling mode, the increased moisture heightens your body’s feeling of heat.

On the other hand, when your HVAC system is undersized, you may experience the opposite with regard to humidity. Just like high humidity may make you feel too warm, low humidity levels can cause other issues, such as chronic dry skin, and respiratory discomfort.

For an oversized unit that is short-cycling, air filtration time is reduced. This will cause air filtration issues resulting in dust and particulates circulating through your indoor air.

High Energy Bills

When your air conditioner is too small to efficiently cool your home, your energy bills may be unusually high. Because the unit has to work so hard to try and meet the demand, it uses far more electricity than it should. On very hot summer days, it can even overheat and shut down completely because the motor overheats or the evaporator coils have frozen. Even though you may set your programmable thermostat to a comfortable temperature, an undersized air conditioner may never reach that desired temperature.

Too Little Power

Although a smaller HVAC unit has a smaller price tag, it may not be worth the upfront savings. If a unit is too small for your home, it will continually be struggling to keep the temperature consistent and comfortable. Some rooms may never be cool enough during the summer when the sun streams in. If this is the case, you may end up having to invest in a supplementary cooling unit, negating any savings you’d have because of aiming small.

Don’t leave your homes HVAC system to chance. Call our professionals at Cook’s Comfort Systems Inc., at 865-238-4835 for accurate sized and professionally installed HVAC systems.

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