The photos below show 2 different technologies to achieve different temperatures throughout a home. A central ducted system can be set up with motorized dampers to let just the right amount of conditioned air into each room…called Zone Control. Ductless air conditioning is a separate system or at least air handler (head) for each section of zone in the building. For zone control to work correctly the ducts need to be oversized as compared to standard design because when one damper closes it restricts the total and the total airflow should not be overly diminished. The air balance trainers at “National Comfort Institute” conducted a study and found that about 80% of residential ducts in the US are undersized as compared to the performance required by the equipment they are connected to. A solution to the undersized duct issue is to implement a hybrid system. We can install a smaller central system at the time of replacement that better matches the duct size you have in your home. Then we add a ductless system to both enhance capacity and add the feature of separate thermostats or zone control. Central air with ducts filters better and or allows for better filters. Ductless air conditioners, aka Mini Split Heat Pumps have better energy savings. This is partly due to the higher rating and secondly due to the fact that there is no thermal loss of the ducts in an unconditioned space when there are no ducts in the first place.
A building with small zones can often be better served with ductless air conditioning or using a combination of ductless and ducted air handlers. The combination is sometimes referred to as hybrid air conditioning. This brings together the amazing energy efficiency of ductless with the good filtration of a ducted air handler.
That being said, Jay Hoover, with 30 years of experience at Integrity Air Heating & Cooling, says he has improved more systems by removing zone control, then by adding it. The biggest reason is most folks do not live in homes large enough to accomodate the volume of oversized ducts needed to make the system work properly. Another negative is the noise. When the controls shut off dampers to cut air flow to rooms that will not be air conditioned, the ducted air handler still needs to achieve 100% airflow and this can create noise through smaller ducts, or worse…it just will not deliver adequate airflow to operate reliably.
However, every single home and situation are unique. We would love to evaluate your needs and discuss options and go over the pros and cons for your home or business. You can decide what is best. Call us for a free evaluation. (813) 932-2665