Most of the time, we would get inquiries or orders with Pre-Selected Equipments either directly by the Client or the Consultant. However, we mostly check the verify the area of application and the selection by ourselves to make sure that the units are sized properly. By this method, we ensure they aren’t Undersized / Oversized.

Most of the Contractors, oversize the A/C Units inorder to ensure that Cooling Demand is met at Peak Load hours. While this might be the easiest way to save hassle just during Peak Loads, this is a complete wrong approach in terms of Energy Saving and Compressor Efficiency. The major issues with Oversizing equipments are.

  • Compressors become weak over time due to repeated Cycling (Cut Off / On) almost instantaneously.
  • Humidity control in the area is not achieved due to high Total Cooling capacity thereby reducing the Room Temperature earlier and less condensation happening. This can cause humidity issues especially in high humid areas.
  • Increased utility bill due to the increased overall size of the unit more than necessary.

On the other hand, Undersizing is also a common issue, which has its predictable outcome, that it doesn’t reduce room temperature to the comfort / setting level.

With the advent of HRW (Heat Recover Wheel) type FAHU’s we are able to transfer energy from the exhaust to the Fresh Air being delivered to the same area. Heat wheels which are efficient above 80 % are available in the current market which, conventionally aren’t implemented due to high initial cost. But, as for the energy saving, it produces a great deal of savings which is better economically as well as for sustainability.



Our Design Engineers makes sure that every Ducts designed and installed under our scope is efficiently sized as per recommendation and the required Air Velocity. Most of the time, contractors either size the ducts without proper calculation either Increasing / Decreasing Air velocity. While increased Air Velocity above 2500 FPM can cause serious sound and vibration issues, oversizing the ducts also can cause improper flow profile inside the ducts.

Ducts with properly designed sizes are also aesthetically pleasing so that it could be used in open ceiling applications as well.


Another area of common mistake made by contractors are the Improper Placement of Indoor / Outdoor Units. For Indoor Units, the important points of consideration would be:

  1. Placing Indoor Units with Water Accessible Area for proper servicing eg. Inside Toilets or similar areas.
  2. Maintaining atleast 400 mm gap between the adjacent wall and the unit against the return side
  3. Access Panels for Filter Access and Future Maintanence in Gypsum Ceiling Area

On the other hand, placement of Outdoor Unit also plays an important role in determining the efficiency of the units and to ensure that the unit works under manufactory regulations. Some important points for consideration of the same would be:

  1. Maintaining recommended gap as per supplier between other Outdoor Units as well as the Adjacent Wall. This is very important since it affects the overall Air Circulation around the units which is required for producing the stated cooling effect.
  2. Water availability for periodic servicing.

AC Space