You can enjoy maximum comfort and optimal efficiency when you separate your indoor air from your outdoor air. Shutting your windows, keeping your exterior door closed, and caulking all cracks and crevices around the perimeter of your home will help you keep the air that your HVAC units generate inside. This allows you more control over the temperature and overall comfort level that you experience within your home. You should also check your outdoor air conditioning unit on a regular basis to ensure that it is free from debris and obstructions. You can also save money and boost efficiency by using a programmable thermostat; set your thermostat to kick in an hour before you return from work to cut down on wasted energy.