Get the clear-cut facts on this window treatment before tinting your home windows.

At war with home windows that are energy-inefficient, weak, or dated? Tinting home windows from the inside with an aftermarket window film is one of the easiest and most economical ways to boost the energy efficiency, safety, even curb appeal of your home without replacing the windows themselves.

While most residential window films are lightweight, self-adhesive polyester coverings made of Polyethylene terephthalate (the same polymer used to make plastic water bottles), not all window films are equal or worthy of your investment. Keep reading to learn about the different options—as well as the benefits and pitfalls of tinted home windows—so you can decide whether this window treatment is right for you and how to install it with the best results.

1. Different types of window film provide different benefits.

There are three main types of window film, each of which is installed on home windows for a different reason:

• • Solar: This option is recommended if improving energy efficiency is your main reason for tinting home windows. Thicker than decorative film but thinner than security film, solar films absorb or reflect (most products do a combination of both) up to 99 percent of UV rays from the sun. This regulates indoor temperature (so rooms stay cool in summer and warm in winter), reduces glare, prevents the fading of interior furnishings, and, ultimately, increases indoor comfort and energy savings. The film is usually sold in neutral tones ranging from silver to copper.

• • Security: If staving off storm damage or deterring burglars is your biggest concern, install security film, the thickest of all types of film. Most security films (usually clear or silver) don’t absorb or reflect much heat. In the event of a storm or a home intrusion that results that damages the window, they do prevent the window from shattering completely by restricting the damage to a large crack, in effect allowing your window to hold out longer.

• • Decorative: As the thinnest of all types of window film, decorative window film absorbs or reflects minimal heat; its primary purpose is to beautify or add privacy to a room. It’s sold as a clear or bold colored film in a variety of etched patterns (such as stripes), stained glass motifs, or opaque frosted designs that keep out peering eyes.

2. Not all types of window film are compatible with all types of window glass.

As noted in the section above, different types of window film absorb varying degrees of heat, which some windows are equipped to handle and others… not so much. Most security and decorative films block minimal heat and therefore don’t place much thermal stress on the windows. Unless your manufacturer discourages it, you can usually apply them to all three common types of window glass—annealed (basic flat glass), heat-treated (annealed glass that has been exposed to high temperatures), and insulating (consists of two layers of glass with an intervening layer of air or gas)—with minimal risk of damage to the window glass.

However, the International Window Film Association recommends avoiding solar film in the following situations because the film’s higher rate of heat absorption can increase the thermal stress so much on these types of window glass that they crack:

• • Clear annealed glass thicker than ⅜-inch or that has a heat absorption rate of more than 50 percent

• • Tinted annealed glass over ¼-thick

• • Insulated glass that is over 10 years old or has had seal failures

When in doubt, check the manufacturer’s literature for your windows to identify a compatible window film.

3. Windows without energy-efficient coatings benefit the most from tinting.

Older windows without low-emissivity (low-E) coatings (a thin layer of metal oxide on the glass) that block out heat stand to gain the most from the energy savings afforded by tinting. Newer windows with low-E coatings already provide homes with a measure of energy efficiency, so your indoor comfort and energy savings may not significantly increase by applying window film to these windows.

4. Renter-friendly options exist.

Solar, safety, and decorative window film are sold in three options for permanence:

• • Temporary varieties that can be repositioned or removed easily and cleanly (great for renters)

• • Semi-permanent varieties that are removable with some residue likely left behind on the window from the film adhesive

• • Permanent varieties that are not designed to be removed

Decorative film is more often sold as a temporary tinting solution, which makes it an option for renters or commitment-phobic homeowners, whereas solar and security film more often tend to be semi-permanent or permanent tinting options, which make them more suitable for homeowners.