According to the National Comfort Institute around half of the new HVAC systems being installed have comfort issues or don’t operate as efficiently as they should. The Energy Star program says that incorrect installation of HVAC systems can reduce efficiency savings by up to 30 percent.
Complaints range from temperature variations from room to room, inconsistent air flow from registers, condensation from high humidity or excessive dust in some areas. These all occur because the system is not correctly balanced.
Incorrect balance can also cause greater pressures in some areas which will push the conditioned air through gaps in the air barrier; and lower pressure in other areas which will suck in outside air. The house can be both pushing air out and pulling it in at the same time. That can happen even if the duct work is properly sealed.
The solution to making an HVAC system operate efficiently and comfortably starts with using the Air Conditioning Contractors of America Manual J to correctly design the system to get all the parts sized right. Rule of thumb is not adequate to get the right air flow to each room at the right pressure and temperature.
The installed system needs to be tested to assure the right amount of supply air is entering each room and that the return air system is taking all the air out of each area that was supplied to it. This will require equipment such as balometers and manometers to measure air flow and static pressures.
Fans need to be adjusted to yield proper air flow. Ducts should be checked to be sure they do not leak. The proper filters should be used.
A properly balanced system allows the equipment to operate at its highest efficiency and save the customer money. It reduces drafts, cuts temperature variations and solves condensation problems from higher humidity levels in some rooms. Proper air flow will reduce the amount of dust carried in the air. Attention to these details will leave the customer satisfied and comfortable and reduce energy costs.