This is a test of commonsense. Complete the next sentence:

How to find air leaks in your home
Use the hand test to find air leaks.
On a cold day with the heat on inside your home, place your hand around the edges of all exterior doors, windows, and bathroom and kitchen air vents and fans. If you feel cold air on your hand, then you have an air leak.
You can also use the hand test to detect leaks around electrical outlets. The hand test is best for finding large leaks of air coming into the home.