6 Factors That Impact Your Home’s Air Balance

Your home’s HVAC system relies on adequate airflow for effective heating and cooling. For systems that use a central air handler, air balancing is critical for consistent temperatures and to maintain the system’s efficiency. Discover what air balancing is, why it’s important, and six factors that will affect how well your system maintains it.

How a Central HVAC System Uses Air Circulation

To begin, let’s explore how an HVAC system with a central air handler heats and cools your home. As you’re likely already aware, your HVAC system conditions the air that’s moving through it. There’s a circulating fan that draws in air from your home, heats or cools it, and then pushes it back out. That’s the simplistic overview of the process. But how does the system distribute that conditioned air throughout your home?

Air always equalizes the pressure throughout the container that holds it, including your home. Your HVAC system creates positive pressure at the supply vents while creating negative pressure at the return vents. This pressure difference causes the conditioned air to circulate throughout your home.

Air balancing ensures that the proper positive pressure is coming from the supply vents around your home and that the system is creating adequate negative pressure at the return vents. There are a variety of factors that may throw that balance off, which will affect how well your system heats or cools your home.

How You Experience Air Balancing

When you have proper air balancing for your HVAC system, you should have nearly even temperatures throughout your home. However, there are several symptoms of an improperly balanced system. 

The first thing you may notice is that some areas of your home are persistently hot or cold. You may see that your heating and cooling bills are higher than normal. When standing next to your supply vents, you may not feel as much air coming from them, even with the damper fully open. For multi-level homes, you may notice temperature swings of more than 2 degrees between floors.

Even if you had your system professionally balanced when it was installed, it might not stay that way forever. These six factors may throw off your air balance over the course of time.

1. Closed Vents and Doors

Vent dampers are used to help regulate the temperature in a room as well as control the airflow around your entire home. When you close your vents, you prevent positive air pressure from building in that area, which then affects how the air circulates throughout your home.

Further, shutting doors can further impact your air balance by restricting the air’s ability to flow to and from the room. While some air movement may still happen, it will inhibit the amount of movement the pressure difference should create. It’s best to leave doors open to help encourage air circulation whenever rooms are unoccupied. 

2. Clogged Air Filter

Your circulating fan is responsible for drawing air into the return vents to create the appropriate pressures at the supply and return vents. Your system has an air filter to help keep contaminants out of the system that will collect and restrict airflow and can damage system components. When the filter clogs, it restricts the air the system draws into it, reducing both the negative and positive pressures it’s supposed to create.

How often you need to change your filter will depend on the size filter you have, how long your circulating fan runs and your indoor air quality. Ideally, check your filter every month to keep an eye on how quickly it’s collecting contaminants and to ensure that you change it before it creates a problem. When you check it, plan to gently vacuum the intake side to improve its service life and give your system an efficiency boost between filter changes.

3. Blocked Vents

Even if you leave your supply vents open, you can create problems by blocking them. It’s easy to do when you’re placing your furniture because a particular piece just won’t fit anywhere else in the room, so over the vent it goes. It can also easily happen when someone in the house unintentionally tosses something over the vent, like toys, blankets, or clothes.

Your vents need enough room to move the air surrounding them. Supply vents need at least a 2-inch clearance extending above and around them. The clearance needed for return vents depends on their size. As a rule of them, plan to keep at least 6 to 12 inches clear, especially in front of the return vent, but check with your HVAC installer to see if it needs more.

4. Faulty Blower Motor

Your system can only move as much air as the circulating fan permits based on the speed it spins. As the blower motor wears, it can fail to spin as quickly as it would when operating optimally. This reduces the effect the system has on the pressures at both the supply and return vents. 

In addition to the blower motor simply getting old, it can also become off-balance. This can increase wear on the motor, causing it to fail prematurely.

5. Leaky and Dirty Ducts

The further away your vents are from your air handler, the less pressure you’ll have at the supply vents. However, when your supply ducts leak, that pressure drops even more significantly. Ducts will eventually start leaking over time as they wear.

The material used to seal your ducts will eventually break down due to the temperature of the air moving through them. Industry experts recommend that you have your ducts evaluated periodically, with average air ducts needing renewed sealing about every five years.

6. Neglected Maintenance

Finally, maintenance is critically important to maintaining the proper air balance in your home. Even when you keep a clean filter in the system, some contaminants will still make their way into your system. They’ll collect on areas like the heat exchanger, the evaporator coil, and on the circulating fan wheel. The longer you allow these contaminants to collect before having the areas cleaned, the more they’ll restrict the airflow through the system, which impacts the air balance.

Ideally, your system needs two maintenance visits each year, one in the fall for your heater and one in the spring for your air conditioner. A technician will clean these areas as part of the routine maintenance they perform. Further, they’ll test your circulating fan to ensure that it’s performing optimally. They’ll also lubricate the fan bearings if it isn’t sealed and will balance the fan as well. These components are just a small part of the entire maintenance process but are the parts that will directly affect your home’s air balance.

Whenever people around Portland need reliable heating and cooling services, they turn to Revival Heating & Cooling. Our expert technicians provide heating and cooling installation, repair and maintenance as well as indoor air quality improvements. We have offices in Vancouver, WA and Portland, OR. Call Revival Heating & Cooling to schedule your home comfort assessment appointment with one of our friendly technicians.