Modern homes find a centralized HVAC system more convenient in every way besides being cost efficient. The same ducting serves the purpose of delivering cool air in summers and hot air in winters. Such systems are quieter than individual units, easier to control and maintain besides being energy efficient. The duct forms the veins and arteries of the HVAC system.
Importance of High Quality Ducts
Ducts play an important role in delivery of cool air from the blower unit. Cross sectional area needs to be finely calculated considering the length of ducting, the air pressure the blower fan is capable of and how quickly the owner may require a room to be cooled down (or heated). HVAC engineers will calculate the frictional losses of the heating and cooling ducts and factor in the length. Bends, T joint and U turns obstruct air flow and their resistance needs to be factored into the equation.
Joins and Insulation
Ducts need to be insulated to prevent losses and maintain thermal efficiency. Thickness of duct insulation and material of insulation used also have a bearing on efficiency. Insulation comprises of simple paper or a better way by using duct liner, board and wrap. If the duct is insulated from inside then the surface must be smooth, which is achieved by using a faced insulation board with the surface in metal or plastic foil. The thickness of insulation must be adequate to prevent losses and needs to be calculated into the overall dimensions of the duct so that efficiency is not reduced and air flow is unhindered.
A side benefit of good insulation on ducting for air-conditioning is the reduced noise. Of course, external insulation is better but available space also needs to be considered. Simple flange joints can be leaky. A loss from gaps reduces overall efficiency and increases energy consumption.
Importance of Design Excellence and Planning
Ducting is not just laying a conduit and hooking it up with the packaged heating/cooling system. Quite a bit of engineering goes into the design and calculations to arrive at the best compromise in terms of airflow resistance, air volume delivery and efficiency. If it were a straightforward simple duct, the matter would be simple enough but when ducting has to be designed to supply air to several rooms in the house and interfaced with grills and other controls, the task of the HVAC engineering firm becomes complex. Only expertise and experience works.
Designing ducting for a house that is at the planning stage is always better because Air Conditioning Company can work with the architect and deliver the best results. A house owner may have opted for split AC or window AC and then discovered the wisdom of centralized air conditioning. In this case, it is not easy to cut chases or drop the ceiling for ducting purposes. In the case of retrofitting, especially when owner is not amenable to cosmetic changes, the AC engineer can come up with innovative solutions such as a high velocity mini duct HVAC system.It can be something as simple as flexible PVC tubing 3 to 4 inches in diameter.
Compromising on ducts for air conditioning is not a good idea. Let your HVAC engineer design it just right for you who will also ensure full compliance with codes and standards, health and safety, cost efficiency and energy efficiency.