Air conditioning jobs are much more than installation of air conditioners. As those with jobs in air conditioning would know, indoor air quality (IAQ) is the most crucial contributing factor to the general health and productivity of all building occupiers.

There is more to IAQ than filtering out airborne pollutants, particles and micro-organisms. Indeed, an important task faced by those with air conditioning jobs is to control relative humidity (RH) in indoor environments, as it makes an incredible difference to the way people feel. If it is above 60 percent, one feels hot and sweaty, regardless of what the actual temperature is within the building. If it is below 40 percent, then the eyes become dry and itchy, particularly for those who were contact lenses.

Research results show that in low-RH environments, one?s respiratory surfaces dry out quickly, which leads to dehydration and reduced resistance to airborne disease-producing agents such as bacteria, viruses and toxins. Worse, because people tend to feel colder than what is justified by the actual indoor temperature, they often turn the heating up, which further lowers the RH and exacerbates the problem.

RH can have a significant impact on the machinery as well. From personal computers to highly sophisticated precision instruments, their energy consumption and ongoing maintenance requirements can be considerably minimised in indoor environments with appropriately controlled RH. Those with air conditioning jobs should keep in mind that the optimum RH range for visual-display terminals is 40 to 60 percent. This is also the range recommended by the World Health Organisation, the National Association Optometrists and the humidity group of the Heating, Ventilating and Air Conditioning Manufacturers Association (HEVAC) as the optimum for offices and commercial buildings.

It is the responsibilities of building owners, building services managers and those with jobs in air conditioning to team up and design humidification into a building from the very beginning. This ensures the most efficient system is installed to provide the best and most cost-effective solution for all building occupiers. Generally speaking, electrode boilers are the cheapest to operate but use as much as 200 times more electricity than an equivalent evaporative humidifier. However, even with evaporative humidifiers, there could be associated costs. For example, because the water in these humidifiers is not being heated to kill bacteria, it is essential to maintain highest hygiene standards in all indoor environments.

Because adding biocides to the water can be expensive, it is recommended that those with air conditioning jobs choose evaporative humidifiers with built-in hygiene management functions. One option is to introduce silver ions to the water by electrolysis before it is evaporated. The silver ions are able to kill all micro-organisms on contact and keep the water safe.

In short, no matter how keen building owners and building services managers are to reduce costs, they cannot afford to ignore health standards. It is vital that those with jobs in air conditioning offer their best advice in choosing and implementing cost-effective ways for managing the RH aspects of IAQ.