Structural Addition Cooling Tips: Should You Extend Ductwork Or Invest In Supplemental Cooling?

Have you recently constructed a home addition? If so, you must determine the most efficient way to cool the extra space. If you have a central ducted air conditioning system, you can extend the ductwork and cool the home addition using the existing unit. However, this option isn't always viable, as it can strain the existing system. Therefore, check out these factors that determine whether to extend your central unit's ductwork or install a new air conditioner. 

Capacity of the Central Cooling System

What is the cooling capacity of your central air conditioning system? Was the system sized to cool only the initial rooms in the home? If you have an AC that is slightly bigger than your home's cooling load, it can handle the cooling needs of one extra room. However, if your current unit is undersized or designed to manage only the initial cooling load, it won't work efficiently. The system will strain to cool the additional room, which will prolong the cooling cycles and cause premature wear to the unit's components. Therefore, consider installing a mini-split to provide air conditioning for the structural addition.

Cooling Load of the Structural Addition

Cooling load refers to the amount of heat your AC needs to remove from an indoor space. This can vary based on the following factors:

  • Size of the room
  • Room usage 
  • Insulation and window glazing
  • Ambient temperatures

A small structural addition acting as a bedroom or living room can be cooled by extending the existing ductwork. However, if you have added an entire story or multiple rooms to your home, you should invest in a new air conditioning system. Similarly, home additions with no insulation and spaces with higher ambient temperatures, such as kitchens and bathrooms, have a higher cooling load. Therefore, they may require supplemental cooling.

Location of the New Space

How far is your home addition from the central air conditioning system? If the additional room is the farthest from the AC, your existing unit may struggle to provide adequate cooling. You will require long runs of ductwork to supply conditioned air to the room. Unfortunately, as cool air travels long distances, it loses energy. As a result, there will be low airflow and inadequate cooling. You need a high-power blower to efficiently push conditioned air into the room. Alternatively, install a mini-split unit in the space to provide reliable cooling.

If your current AC cannot handle the addition, don't extend the ductwork, as this may cause inefficient cooling throughout the home. Instead, install a mini-split unit in the new space. Contact an HVAC contractor to learn more about air conditioning installation and ductwork retrofitting services.