If you want to prevent leaks around your vinyl windows, you need to make sure that the windows on your home are installed properly. Proper installation is crucial for making sure that your windows don't leak; leaking air from your home can really reduce the energy efficiency of your vinyl windows.

#1 Tuck the House Wrap

The outside of your home has insulation on it, and on top of the insulation is a layer of house wrap that is designed to improve the energy efficiency of your home. Your siding goes on top of the house wrap.

The house wrap should be cut so you have enough to wrap around the window. You are going to want to take the house wrap and tuck it around the opening for each window. Secure the house wrap on the bottom of the window with a staple or two. On the sides of the window, use a couple of staples to secure the house wrap on either side.

Don't put unnecessary cuts on the house wrap -- the house wrap is designed to keep water from getting behind the siding and into your home. It also helps keep air from leaking around your windows.

#2 Install Sill Flashing

Second, you want to make sure sill flashing is installed with the window. You can purchase still flashing from the same manufacture you purchase the window from, or you can purchase aftermarket sill flashing; the key is to make sure the sill flashing is installed with your window.

Sill flashing helps keep water out of your home and also helps prevent drafts around your window. You want to use flashing that comes with three parts – two corners and a center section that you need to cut down to fit your particular window.

Make sure when you nail down the flashing that it goes over the house wrap. If you need to adjust the sill flashing, that can be easily done with some tin snips. Secure the flashing in place using roofing nails. Put caulking over the area where the sill flashing overlaps where you cut it in the center to make it properly fit your window opening. Caulk over the nail heads as well -- you want to create as waterproof a surface as you possibly can.

Before installing a new vinyl window, you want to make sure you tuck the house wrap around the window opening and install sill flashing. These two important steps will help ensure that water and air don't leak around your new window.