Attic insulation is the best way to regulate your home’s temperature. By preventing conditioned air from escaping through your ceiling, it can help keep your home warm in the winter and cool as a cucumber in the summer. But only if you have enough of it.

For many people, adding insulation to your attic is a simple thing that can make a big difference. But if you’re not sure whether your home can benefit, check out this short video from Energy Star that can help you decide whether your attic could benefit from a little extra stuffing.

A quick visit to your attic with a flashlight and a tape measure is all it takes to know for sure.

1. First, be careful not to fall through the floor. You’ll only be adding to your to-do list, and even well toned calves will look comical sticking through a hole in your bedroom ceiling. If you have trouble finding safe footing, find a partner to spot you.

2. Next, measure the depth of your attic insulation. If it seems uneven, you may need to measure at high and low points.

3. Finally, consider your results. If you live in the southern U.S., 13 to 14 inches of insulation is a good target, but those living in northern states should have between 16 and 18.

It’s important to note that the EPA recommends air sealing your attic before installing additional insulation. Energystar.gov has tips on how to Rule Your Attic, including the series of videos, which begins with the measurement process and covers air sealing and installation as well.