Another important step to preparing your HVAC unit is to replace the filter. The filter catches particles before the air flows into your home, so it has likely built up plenty of dust, dander, and allergens. Ideally, you should replace this filter every month. If you have not replaced it through the cooler months, now is the time. This way, your unit will have a nice, new filter before it begins working hard all summer long.
If you have difficulties with allergies or asthma, then it may be a good idea to install a HEPA filter. HEPA filters are designed to catch very small particles, which can improve indoor air quality.