In order for your AC system to cool your Los Angeles or San Fernando Valley area home, it needs a way to deliver the air. It does so by using your air supply ducts.
Air supply ducts transport the air from the air conditioner to the rest of the house. Properly designed duct systems can ensure uniform temperatures and regulate efficiency, saving you money in the process. 
Efficient ducts deliver clean, fresh air to each room in correct quantities. The size of the ducts is critically important to the efficient operation of the entire HVAC system.
Type of HVAC and Duct Size
The type of HVAC unit determines the size of the duct system, as a pump requires larger ducts than the typical air conditioner system, the desired indoor air quality will also affect the size of the ducts. For example, air cleaning filters cause more resistance to the air flow, which requires an adequate return air system.
Designing a properly sized system that will match your HVAC unit will save you real money on monthly utility bills. Typically, smaller duct systems require fewer repairs and last longer.
Ducts and Temperature Differences
Well-designed ducts can maintain uniform temperatures throughout the house, efficiently and quietly, but poorly-designed, or improperly installed ducts, can cause temperature differences within the house. Those that leak, or do not distribute air properly, make some rooms too hot and others too cold.
A poorly designed duct system uses more energy to get air to every room to keep you comfortable. Sometimes, the ducts might be designed well, but the system may not have been installed properly. This is usually the case if the installer did not seal all the leaks. Such an unbalance results in more energy being used, because the right amount of air is not going to each room.
The Importance of Duct Size
Oversized or undersized ducts can lead to low air flow, and uneven temperature distribution. Either problem can also make your AC system noisy. Undersized ducts, or those that have numerous bends and turns, may lead to low air flow rates and high air velocities. Low air flow rates cause the cooling equipment to operate inefficiently, while high air velocities increase noise. Both can make a home uncomfortable.
Improper duct size can also shorten the life span of your AC equipment by constantly making it work harder than it should. If Los Angeles area home has either oversized or undersized ducts, you should call an HVAC technician, who can recommend the correct adjustments.
Efficient Duct Systems
An efficient duct system should have a balanced return and supply to reduce air noise, a maximum air flow, and no leaks. Ducts should be located within conditioned spaces, such as between floors of a house. This reduces temperature loss or gain from surrounding conditions.
Good ductwork should save you money while cooling your home. If your duct system is poorly designed, has leaks, or undersized ducts, your AC equipment will not work at its full capacity, and your energy bill will be high. To resolve these issues, you should have your duct system inspected by a professional. With proper duct design, you will have a healthier, and a more comfortable home.