As summer approaches, the last thing you want to deal with is your old air conditioning system finally packing up and leaving you dealing with the excessively hot conditions. That’s not to say that your heating breaking down in December is any more welcome. This is why it is crucial to ensure that your HVAC system is properly sized and installed. An HVAC system that is too large or too small can be more than an inconvenience and can lead to excessively high energy bills or even health issues. So, here we’ll explore how you should size an HVAC system.

Forget One Size Fits All

The most common mistake that homeowners can make when considering HVAC units is to assume that there is a one size fits all solution. This can be a costly mistake, and you can’t assume that you can buy the same unit that your friend has simply because their home is a similar size. You cannot simply work out the square footage of your home and assume that you can choose a new unit solely based on this information.

If you try to use a formula that is based just on the square footage of your home, you are likely to end up with a system that is too large for your home. This will mean that you will end up not only paying more for your HVAC unit, but also pay more to install and run the system. A larger unit will fail to accurately maintain your desired temperature, so you will end up paying far more in your energy bills.

Additionally, don’t assume that you can simply purchase another unit that is the same size as your current system. This could compound your HVAC issues, as there is no guarantee that your current system was properly sized or that other factors have not changed since its installation that would impact the sizing requirements.

The Variables to Consider for Sizing Your HVAC Unit

When you hire an experienced and reputable HVAC professional to size your new system, there are a number of variables that they will consider. These include:

  • The age of your home: Older homes and office buildings tend to not have adequate ductwork or ventilation to accommodate the requirements of a new HVAC system. It may be necessary to have an HVAC retrofit to ensure the maximum efficiency of your unit. Another consideration for older homes is the condition of your electrical system; it will need to be up to code to handle a new system.
  • The windows: The condition and number of windows in your home will also have an effect on the size of HVAC unit needed, but this is only part of the information. The actual location of your windows will also be a contributing factor. For example, if your windows are south facing and receive a lot of sunshine throughout the day, more heat will be entering your home. Your cooling system will need to work harder throughout the summer to maintain your desired temperature, but your furnace will need to produce less heat in winter. The type of window will also impact your HVAC requirements. Single pane windows lack the insulation properties of double or triple paned windows, so there is a greater chance of your cooled air escaping and forcing your HVAC system to work harder. Even your choice of window treatments can figure into the calculations.
  • Home location: The location of your home can also have a major impact on your heating and cooling needs. For example, if there is some shade around your home that will block the sun, your home will be able to be kept cooler. Shade trees could improve the efficiency of your HVAC system by up to 20 percent, so your home location can have a profound effect on your HVAC efficiency and the size requirements.
  • Insulation: The type and amount of insulation in your home will also be a factor for maintaining consistent, comfortable temperatures. Your HVAC technician will include the R-value of your home in the load calculations to properly size your system. If your home does lack insulation, it may be possible to add more during the ductwork installation.
  • Weatherstripping: Finally, your HVAC technician will assess your weatherstripping to detect and remedy any air leaks. It may be necessary to add weatherstripping around the doors and windows of your home to ensure the maximum efficiency of your new HVAC unit.

The Consequences of Poorly Sized HVAC Unit

When an HVAC unit is too large or small for your home, you will experience inconsistent heating and cooling. The unit will either run in short bursts or operate nonstop throughout the day. You may also notice more moisture in your home, as the unit lacks the power to adequately maintain your desired temperature and remove moisture from the air. This can ultimately lead to mold or mildew growth that can compromise your health.

As we touched on above, many people assume that opting for a larger HVAC system is a good idea, but it can be problematic. When an HVAC unit is too large, it will not run for a long enough period to condense the air accumulated on the coils, so the air will not be effectively dehumidified. You may also find that the unit produces more noise, so it will not only use more energy, but also disturb your home comfort.

Call in the Professionals

Although it may be tempting to try and size your HVAC unit yourself and buy equipment from a big box store, as we’ve demonstrated, this is not a simple matter. While it may appear to be a more cost effective option, it could end up costing you far more in the long term. Therefore, it is a better idea to call in the professionals and have an experienced HVAC technician size your HVAC unit. Your technician will use reliable methods to calculate the most energy efficient and cost effective size and model of unit for your home.