We did a performance check on a high efficacy York heating and cooling system today. Furnace heat is working intermittently, customer said that she is also having an issue with her thermostat. After inspecting the furnace we noticed that the air filter was extremely dirty and the dirt buildup was not allowing air to pass. Installed new filter and the system was running as designed once again.
Pro Tip: To get proper airflow in your HVAC system, you should always have the filter’s arrow pointed towards the indoor unit. Always change your 1″ thick filter once a month and never use any filters higher than a MERV 10 level to get the required proper airflow. High MERV rated filters are designed to catch large and small particles. Since it can catch the smaller particles, the opening is also smaller and will get dirty quickly. Additional, 1″ filters are thin and will quickly fill up with particles blocking airflow.