The straightforward answer to this question is “no.” Modern central air conditioning systems are complex refrigeration devices, and to work on them requires special training as well as tools not easily available to the consumer.
The biggest obstacle against trying to do DIY work on an AC is the difficulty in diagnosing what’s causing a malfunction in the first place. For example, if an air conditioner keeps shutting down early (short-cycling), it could be due to a miscalibrated thermostat, leaking refrigerant, a reduction in airflow, dirty condenser coils, etc. Trying to repair a problem yourself will involve too much guesswork and too much that can go wrong.
The answer is: quite a lot! Energy recovery ventilators (ERVs) are special devices that professionals can install into HVAC systems to allow for better indoor air quality without the sacrifice of significant energy efficiency indoors.
The most common nugget of wisdom we impart to our customers to help them help their furnaces is to regularly change the furnace filter. This filter is usually located on the HVAC cabinet at the point where the return air ducts connect to where the blower is located. The filter does the job of blocking debris coming through the return air ducts so it won’t enter the cabinet and contaminant the furnace, blower, and other parts of the HVAC system. This filter isn’t self-cleaning, and after one to three months the congestion in the filter will start to cause problems and even lead to damage to the furnace. 
We want to start this blog with an assurance: gas furnaces are not inherently dangerous appliances. They’re found in millions of homes across the country, dutifully keeping families warm. Provided they receive regular maintenance and professional repairs as necessary, they can run at high degrees of safety throughout their service lives.
The simple answer to this question is 
You never want to start the cold weather months with a furnace that doesn’t seem up to the job. You want to know that after you turn the furnace on for the season and make the adjustment to the thermostat that you’ll receive the right amount of warmth for your family’s comfort. If your furnace isn’t keeping up the cold, there may be something wrong. It might be minor. Or it might be something that will require you to call us for