Air balancing has typically been the domain of commercial HVAC contractors. Large buildings with powerful air conditioning units need their air ducts laid out perfectly to ensure that each room receives the appropriate amount of conditioned air.
However, this service is very important for residential customers as well — many homes suffer from hot or cold spots because air is not flowing through the ductwork properly. An air conditioning contractor can measure airflow in the rooms in your home and make changes to your home's air ducts in order to ensure that air is flowing through the system smoothly.
When should you consider having this service performed? Below, you'll find four occasions when you may need your home's air balanced.
One of the Rooms in Your Home Is Always Too Hot
One of the most telling signs that your home has an air balance problem is when one of your rooms is always uncomfortably hot. This means that the room isn't receiving enough conditioned air through its register.
This is often caused by a leak in the air duct running to the room. The conditioned air leaks into a crawlspace before it can even reach the room it's supposed to go to. Repairing the leak will restore the room to a comfortable temperature.
However, it can also mean that another room in your home is receiving too much conditioned air. This is usually caused when the room is far away from a junction in the air duct. Air in your home's ductwork will always take the path of least resistance, so it's not apt to travel long distances — it will flow towards closer rooms instead. Adding dampers to the other rooms connected to the junction will increase air resistance in those ducts, making the conditioned air in your ducts more likely to travel to the faraway room.
You Hear Air Rushing From a Register
If you hear air rushing from one or more registers when your air conditioner first turns on, you likely have high static pressure in your home's ductwork. This can be caused by your air ducts being too small, poor return airflow to your air conditioning unit, or a bend in an air duct that has compressed it.
Whatever the cause, the end result is that the blower fan in your home's air conditioning system will struggle to move air around your ducts. When the air finally reaches a register, it'll erupt and create a loud rushing sound due to the high pressure behind it.
Improving return airflow to your air conditioner, expanding your ductwork, or replacing collapsed ducts with new ones will solve this problem. It's also an important problem to address, as the motor on the blower fan will be under a substantial amount of stress trying to move air around in a system with high static pressure — this makes it more likely to fail earlier.
You're Upgrading Your Air Conditioner
When you change your air conditioning unit, it's likely that the new model will move air throughout your home at a different rate than the old one. This can easily lead to air balance problems where none existed before. For example, a more powerful air conditioning system can lead to drafts in a room unless the damper in the duct is lowered more. Whenever you upgrade your air conditioning unit, the design of your home's air ducts need to be examined as well.
You're Planning on an Addition or Renovation
If you're adding a room onto your home or making a major renovation that eliminates an existing wall, you will radically change the way that air flows around your home. Whenever you change the design of your building envelope (all of the space in your home that's conditioned), you'll need to change the ductwork in your home as well. For example, a room that has become larger may need its associated damper raised to allow more air into the expanded space.
Overall, air balance is an important part of keeping the entirety of your home at a comfortable temperature. Unfortunately, it's neglected by many homeowners. If you have hot or cold spots in your home or if you have made changes to the way it's laid out, call an air conditioning contractor to have each room's airflow measured. They'll be able to make the necessary changes to your home's air ducts to ensure that each room is receiving the appropriate amount of air.