Are your heating and cooling unit not working properly?
If your HVAC system is acting up you should probably find heating and air conditioning repair company to come and take a look. If you have enough knowledge to fix your heat pump or AC unit then great, you can save yourself some money. But if you are not 100% sure that you can properly diagnose and fix the problem yourself then do not touch your system. If you do not fully understand what you are doing you could actually cause a much bigger problem within your central air system.
The smartest thing to do in my opinion is to contact an HVAC contractor and set up a routine service call. The service call itself is not that expensive and the heat and AC contractor will take a deeper look into your system to see if there are any upcoming problems. If they do find some more serious problems they will notify you before trying to fix them.