All ventilation is essentially dilution, where the ventilation process acts to change polluted indoor air with outside or fresh air at a rate that will keep the impurities and substances at a safe and acceptable level.

It is the lack of adequate dilution that most often results in wide and varied occupant responses: “It is too stuffy”, “it’s too hot”, “it’s too cold”, “what’s that smell?” and “I get tired in the office”. From elevated CO2 counts to Volatile Organic Compounds (VOCs), the source is a lack of adequate fresh air to dilute the pollutants that will always be present in any indoor environment.

Often the reason is as simple as ensuring the outside air damper is open:

This closed damper is preventing any outside air from entering the building and in a busy office with all the occupants breathing out CO2, office equipment emitting VOCs, lunches being heated up and the like, the office is very likely to be rather stuffy and uncomfortable by the afternoon.

But a major culprit in the reduction of adequate dilution is a dirty system.

Often, by the time Machado is called to quote cleaning the HVAC system due to occupant complaints, the cooling or heating coils are already partially plugged from either dust that got past the filters or from fiberglass fibers that got blown off the liner.

Plugged coils often restrict the air flow 30 to 50%. That means 30 to 50% less air going into the building and 30% to 50% less lovely fresh outside air (if that's possible in L.A.!).

VOC's from desks, chairs and carpets “off gas” continuously. High concentrations of these can impair the immune system. Normally, the air circulating in your building will keep the concentration of VOC's diluted. But with reduced air flow they can build up.

It is not simply the dirty coils that restrict the air flow. Filters that have been in place too long will virtually stop any air flow.

These filters are collapsing from the pressure. The result is contaminated (or plugged) cooling coils, reduced fresh air and a system that will accumulate dirt and debris in a geometric fashion.

Deteriorating fiberglass and other debris will build up on turning vanes and other components dramatically reducing any kind of adequate ventilation.

This solution to all of this is, of course, keep the air flowing and the outside air being brought into the building. But no amount of adjusting dampers or controls will overcome the effects of a dirty system.

Keep the HVAC system clean to ensure an adequate amount of fresh air and keep those occupants alert, not groggy.