Winter brings an alternate form of water for those in the northern climates, snow. Keeping snow from the internals of an HVAC system is important. Snow can penetrate the system much further under drifting or blizzard conditions than rain will in a wind storm. Control of this situation will prevent snow from accumulating on the supply air filters, clogging or melting and supporting microbial growth.
Keeping an eye on the situation is important as well as monitoring the pressure drop across the filters. Pressure drop alarms and magnahelic gauge monitoring are both very effective.
The outdoor air intakes need to be properly located to prevent snow from entering the system. If they are not well located, the utilization of mechanical separation needs to be implemented. Louvers can work if the air intake volume can be modified without decreasing system performance. Pre-filters will do a great job of preventing snow from reaching the additional downstream stages of the filtration system. Pre-filters can easily be changed when needed and are the first line of snow defense in the absence of other mechanical means.
Preventive air intake screens offer superior performance for the prevention of snow. The screens can prevent the snow from entering the system while maintaining the desired pressure drop for ideal system performance. A quick swipe of a broom will remove the snow build up and make the maintenance fast and simple.