Using your HVAC in winter and in summer puts the system through different types of strain. When winter is coming to a close, that's the time to get the system ready to switch into summer mode. This is also sometimes called de-winterization, and it requires a few steps that are, luckily, fairly easy.
New Filters (Yes, It Will Always Need New Filters)
Has it been a while since the filters have been changed (or cleaned if they're reusable)? If so, it's time to change them. Many systems even recommend changing the filters monthly, but if you've forgotten to do that, then this is a good time to take care of the task. Putting in clean filters helps these systems work more efficiently while trapping pollen and dust.
A Complete Inspection
Your HVAC system has been in use for much of the winter as you warmed your home, and any outside components have been exposed to very cold weather. And then there's the normal deterioration that happens slowly as the system ages. Whenever you're about to switch from using the furnace to the air conditioner and back again, you want to put the system through a full inspection. Have a maintenance person look over everything to ensure that when you start using the air conditioner again, it will work very well.
Check Your Thermostat Settings
It's always good to give your thermostat another look. Change the batteries if you haven't changed them for a while, and review the programs if the model you have is programmable. Ensure that the settings are appropriate for upcoming warmer weather that could also dip back into colder temperatures occasionally.
Prune Trees and Bushes That May Grow Too Close to Outdoor Components
When the trees and bushes in your yard start to grow again in spring, they'll send a lot of new growth out, and some of that could end up right up against the outdoor components for central and mini-split systems. Those plants need to be trimmed in late winter so that the new growth has more room. While that's not something you'd call a plumbing or HVAC company about, it is a necessary step in preparing your HVAC system for spring.
It may seem like you're constantly preparing your HVAC system for yet another season, but that's part of what goes into keeping the system in good shape. Contact a company that works on HVAC systems (this could be an HVAC-only company or one that handles plumbing and air) and arrange for de-winterization.
For more information on HVAC maintenance, contact a professional near you.