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HVAC System: Choosing the Right Size

Air Conditioner

If you are looking to replace your old HVAC system or would like to upgrade to a new one, it is actually quite simple as long as you take several important factors into consideration. By doing so, you will be assured of consistent efficiency as well as long lasting comfort from your HVAC system.

Find an Expert

One of the most common mistakes that homeowners make when upgrading or replacing their HVAC system is thinking that anyone can do the job. To ensure that your new HVAC system will provide you will all your air conditioning needs, hiring an expert technician is the right way to go.

With an experienced and skilled HVAC technician, you can rest easy knowing that the right system has been installed in your home. Not surprisingly, determining the correct air conditioning system is usually done by knowing which among the many sizes of air conditioning unit will meet all your home's needs.

Oversize or Undersize?

Air Conditioner

As a general rule, the size of the air conditioning unit is chosen by utilizing different calculations, which considers factors such as heat gain, tonnage and square foot analysis. Some experts recommend over-sizing while others prefer undersized HVAC units. But most HVAC professional contractors rely on the Manual J – a booklet that will allow technicians to calculate the right size of the air conditioning unit by using heat gain.

The Heat Gain Factor

Simplifying the Manual J, you will observe that the heat gain factor usually considers the following:

  • Heat Gain through Glass/ Window Surfaces – most direct and largest heat gain source
  • Heat Gain via Exterior Doors
  • Heat Gain through Ceilings, Floors and Walls
  • Air Infiltration
  • Latent Heat Gains

After considering the heat gain via all these sources, you will be able to successfully determine the proper air conditioning unit size. Make sure that your HVAC technician is aware of this kind of calculation if you want to ensure a cost-effective and energy- efficient HVAC unit.

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