When it comes to painting the outside of your windows, look for a quality exterior trim paint. Trim paint is specially formulated to be tough and long-lasting. When you’re painting, don’t worry about getting some paint on the glass. Just wait until it’s dry, then use a single-edge razor blade to scrape off the excess.
When painting double-hung windows, start by removing the sash. Put the sash on a couple of sawhorses or a work table. If you can’t remove the sash, then work carefully so you don’t paint the window shut. Paint the sides of the vertical stiles first, using a 2-inch trim brush with just a small amount of paint.
Beginning in the upper left corner, paint downward until you reach the bottom of the sash. Lift up on the brush at the end of the stroke. Continue until the sides of all the vertical members are completed.
Paint both sides of any vertical and horizontal grills in the sash. If you get paint on the glass, let it dry, then scrape it off with a single-edge razor.
Now, paint both sides of the rails (horizontal sash members) on the upper sash.
Paint the faces of the grills, rails, and stiles on the upper sash. When completed, repeat the process for the lower sash.
When painting double-hung windows that are still in the jamb, pull the upper sash down and raise the lower sash so you can paint the surfaces that touch each other when the window is closed. Let the paint dry completely before closing the window.
Return the sashes to their normal position and paint the stops and jambs.
Paint the sides of the casing, then the faces of the casing, and continue to the sill. Use masking tape or a paint shield to keep trim paint off the siding. If you use tape, be sure to remove it as soon as the paint is dry to the touch.