As you may know, the latest air conditioners come with high SEER value. SEER value shows the efficiency of the cooling system and a high SEER value indicates a highly efficient cooling system and vice versa. Checking the SEER value of your air conditioner can also help you decide whether you should repair or replace it.
If your cooling system is older, it will have a low SEER value, which means it does not work as efficiently and will cost you heavily in the long run.
Similar to SEER, the AFUE value of your furnace determines its efficiency, and the same rule applies to your heating appliance. Replace your furnace if it has a low AFUE value, and maintain it with regular repair jobs if it has a high AFUE value.