What you can check safely
Look at the thermostat first. Make sure it's set to heat and the set point is actually above room temperature. Check the breaker panel for a tripped breaker on either the indoor or outdoor unit. Go outside and look at the outdoor unit. If the coil is caked in ice beyond the thin frost that's normal in defrost cycles, that's worth noting for the contractor. Pull the air filter and hold it up to a light. If you can't see light through it, replace it. None of this calls for opening any panel that needs a tool to remove.








