Yes. The first thing to check before turning on your unit is to make sure the condensing unit located outside is not covered up. The unit needs to draw air into the system in order to have something to cool and blow out inside, but the process is hindered if it cannot pull enough air in from outside.

We're amazed how many homeowners call because their air conditioner isn't cooling their house, only to find they forgot they had temporarily stacked lawn furniture, bags of leaves and lawn clippings, etc. around their outside unit over the winter. Some people intentionally cover their condenser to "protect" it from the elements during the winter, although these units are designed for outdoor installation and require no protection at all.

Here are some basic tips:

1. Run your air conditioner for a few minutes now, before you need it. If you wait until the first hot day to discover is isn't working, you'll find yourself on a waiting list, sweltering sometimes for days before an air conditioning specialist can come to fix it.
2. Change the filters regularly. Dirty filters restrict air flow, reducing efficiency and worse case, can cause the evaporator to ice up. Disposable fiberglass filters should replaced. Electrostatic or electronic filters need to be washed regularly.
3. Be sure all access panels are secure, with all the screws in place.
4. Clean obvious obstructions such as newspaper, leaves, etc. from around the exterior of the unit.
5. Be sure the thermostat is set in the cooling mode. Just setting the dial below room temperature will not activate the air conditioning if it is set in the heat mode.