Central AC should run 2 hours before office opens: Haryana govt

CHANDIGARH: Sounding a word of caution on the use of central airconditioning in institutions and malls in view of the prospects of Covid-19 spread, the Haryana government on Thursday said it is advisable to avoid central airconditioning to the extent possible.

Adopting new central guidelines prepared by central public works department (PWD), the state government said if running central air-conditioning becomes unavoidable, then airhandling units (AHUs) of central ACs should run on maximum fresh air two hours prior to the opening of office and two hours after the closing to ensure that no contamination remains.

AHUs are the lungs of a heating, ventilation and air conditioning (HVAC) system. It is a device used to regulate and circulate air as a part of HVAC system. It takes outside air, filters it, cool or heat it and supply it as fresh air to the air-conditioned area.

The guidelines also said that AHUs are advised to be operated on maximum fresh air and heat recovery wheels should not be used at all. Experts said that thermal wheels allow transfer of heat between two adjacent airflows and help in saving energy.

The air being expelled is used to cool the hot incoming air during summers using thermal wheels. The best cooling options without aiding infection or contamination are window-fitted desert coolers, window and split ACs, fans aided by maximum fresh air intake by opening doors and windows and supported by air replacement through exhaust fan facilities in nearby areas, stated the new guidelines.