Here are some simple things homeowners can check before calling: 1. Check your thermostat—Do you have it set for heating or cooling and is the choice appropriate for the season or is it inadvertently in the "off" position? 2. Check the air filter. If it’s very dirty – if it hasn’t been changed in months and it’s clogged with dirt – your system’s working hard to get ANY air through. Replace the filter and see if the system then operates properly. 3. Check that nothing is blocking the free access of air to your outdoor unit—this applies to air conditioners and heat pumps. Shrubs and bushes can block and restrict airflow to outside units and snow can drift against outdoor heat pump coils. 4. Check your electric fuses or breakers. As you know, your HVAC system uses electric power to do its job. Your load center has fuses or circuit breakers. One or more provides power to the HVAC system. You might have one for the furnace and another for the air conditioner. For a heat pump, one is usually provided for each separate piece of heat pump equipment; one for the air handler and one for the outside unit if you have a split system, for example. If the fuse is blown or the breaker has “flipped” to the “off” position, you can play with the thermostat forever and you won’t accomplish anything! It is kind of wasteful to call a service person to “throw” a circuit breaker! However, that is one of the first things our service people check. And you’d be surprised how often a service call consists of not much more than resetting the circuit breaker. Additionally, your unit might have one or more Disconnect Switches. Perhaps your home has such a switch outside the house. Perhaps a mischievous youth moved the switch from “on” to “off” without you knowing it. If you reset a circuit breaker or replace a fuse and it immediately trips or blows—call us for expert service assistance. 5. HVAC experts recommend regular replacement of dirty filters. Perhaps you have done the required thing and replaced the filter very recently. Very soon after that effort, you might discover the system isn’t doing the job! If the filter was in the HVAC equipment, go back and check that the system’s fan door is installed properly. Many heaters have a door interlock switch. Your furnace probably will not begin operating until the access door is tightly in. Others simply will not work well if the access panel is allowing air to bypass the unit.