An undersized HVAC system may not always be apparent from the onset. It could be caused by various factors, such as a lack of proper insulation, leaky ducts, or changes to the building, such as adding rooms or extensions.  A qualified HVAC professional will be able to conduct a load calculation to determine the appropriate size for your HVAC system, taking into account factors such as the square footage of your home, local climate, and energy efficiency. Below, we look at four signs that your HVAC system is undersized.

How to Understand Your HVAC Unit Size

HVAC unit size refers to the unit’s heating and cooling capacity, typically measured in British Thermal Units (BTUs) for heating or in tons for cooling. The size of the HVAC unit is determined by a load calculation, which takes into account factors such as the square footage of the space, the number of windows, the type of insulation, and the local climate. An HVAC size calculator determines the amount of heat gain or loss in a building. It takes into account factors such as the size and layout of the building, the number of windows, the type of insulation, and the local climate. Once the load calculation is done, the HVAC contractor will be able to determine the appropriate size of the HVAC unit that’s needed to heat and cool the space effectively.

4 Ways to Tell if Your HVAC System is Undersized

1. Short Cycling

Short cycling refers to when an HVAC (heating, ventilation, and air conditioning) system turns on and off frequently without fully completing a heating or cooling cycle. It happens when the thermostat calls for the HVAC system to turn on, but the system doesn’t run long enough to reach the desired temperature before turning it off again Short cycling can have several negative consequences, such as:

  1. Reduced energy efficiency:

    When the HVAC system is short cycling, it is running less efficiently and consuming more energy than it would if it were running for longer cycles.

  2. Reduced comfort:

    When the HVAC system is short cycling, it is not able to effectively heat or cool the space, leading to uneven temperature control and discomfort.

  3. Increased wear and tear:

    Short cycling puts additional stress on the HVAC system, leading to increased wear and tear on the equipment and potentially shortening its lifespan.

  4. Reduced air quality:

    If the HVAC system includes an air cleaner, it may not have enough time to filter the air during short cycles.

2. Inability to Reach Desired Temperature

An undersized HVAC system may struggle to heat or cool space to the desired temperature, leading to uneven or inadequate temperature control. There are a number of reasons why an HVAC system may not be able to reach the desired temperature:
  • Insufficient capacity
  • Clogged air filter
  • Faulty thermostat
  • Leaky ducts.
  • Refrigerant leaks
  • Dirty coils or condenser
  • Incorrectly set thermostat
It’s important to have an HVAC professional diagnose and fix the problem. They will be able to identify the cause of the issue and recommend the appropriate solution, such as replacing the thermostat, repairing the ducts, cleaning the coils or condenser, or adjusting the refrigerant levels.

3. High Energy Bills

An undersized HVAC system may not have enough capacity to heat or cool the space to the desired temperature effectively. This means that it will have to run for longer periods of time to try to maintain the desired temperature, resulting in higher energy bills. The system may turn on and off frequently without fully completing a heating or cooling cycle, a phenomenon called short cycling, it will have to work harder to keep the temperature stable, consuming more energy and causing higher bills. An undersized HVAC may not have enough capacity to effectively remove moisture from the air, leading to increased humidity levels in the home. This can cause discomfort and also damage to the home and furniture, making the system work harder and increasing the energy bills.

4. Increased Humidity Levels

An undersized HVAC system may not have enough capacity to remove moisture from the air effectively. This means that it will not be able to keep up with the amount of humidity that the space is producing, leading to increased humidity levels in the home. As the undersized HVAC system is not able to reach the desired temperature in an acceptable amount of time, it will turn on and off more frequently without fully completing a heating or cooling cycle. This process is called short cycling, which makes the system not run long enough to effectively remove moisture from the air before turning it off again. Many HVAC systems include dehumidifying features. If the system is undersized, it may not have a strong enough dehumidifying component, making it difficult to remove moisture from the air effectively.

Schedule HVAC Installation Service in Alexandria, Virginia

If your AC system breaks down and you need AC installation, we are ready to help. Cardinal Plumbing, Heating & Air offers complete HVAC services in Alexandria, Virginia. To schedule service, fill out our contact form or give us a call to get an estimate.