Summer and winter are the most stressing seasons for any heating and air conditioning system. Like any piece of equipment – a vehicle, a surgical tool, a television – your HVAC system is designed to operate within a set range of conditions. The closer to the edge of design, and occasionally beyond, that the system operates, the more stress the system is under. But we should not overlook the stress a shoulder season can put on a system: pollen and leaves. The system can be clogged by either and lose the efficiency we designed and our clients bought.