Firing up your heater? Here are some cold-weather safety tips to know Protect your pets, homes, plants from freezing temps Sophia Beausoleil, Reporter Updated: Tags: HVAC systems As the temperature drops, the number of calls for HVAC technicians has increased as people start to use their heaters. David Bedingfield with Air Specialist Inc. said there are multiple reasons why units fail. “A lot of it is lack of maintenance; also, dirty filters or anything like that can contribute to a failure at that point in time," Bedingfield said. He said because dirty filters can disrupt air flow, it can cause carbon monoxide to be released into the house, which is itself a danger. He also said it can cause the motor to not operate, which can cut the system off.