Exterior paints offer a wide range of color options, just like interior paints. However, it’s important to note that each type of paint is specifically formulated to perform the best in its intended environment. While it’s possible to use exterior paint indoors, better options are available. Here are some reasons why there may be better choices than using exterior paint inside your home.

Exterior Paint Formulations

Exterior paints are formulated to hold up to the great outdoors. A premium latex exterior paint relies upon flexible acrylic resins that expand and contract with a home’s siding during extreme weather fluctuations from hot to icy cold. These paints are highly water resistant and contain ultraviolet-blocking additives that prevent premature breakdown from the daily punishment of direct sunlight. Other additives protect against mildew spores and tannin stains from wet falling leaves or bleed-through from sappy wood knots.

Interior Paint Chemistry

Unlike exterior coatings, interior paints are designed to endure heavy indoor traffic’s wear and tear, including bumps and scrapes against walls and woodwork. The details matter for indoor-painted walls, which are viewed up close, and that’s why interior paints contain special resins and additives that produce a durable, smooth finish that can withstand regular dusting or scrubbing. On the other hand, exterior siding is typically seen from a distance, so exterior paint is formulated to provide protection against harsh weather conditions rather than close-up scrutiny.

Interior wall paints also include additives that minimize spatter during application with a brush or roller.

Indoor Air Quality

Because of health and environmental concerns, modern indoor paints produce minimal odor and minimal toxic emissions. By contrast, exterior paints usually out-gas into the great outdoors, where chemical emissions are less apparent. When exterior paints are used within enclosed indoor spaces, the chemical fumes — including volatile organic compounds, strong mildewcides, and other potential health hazards — can linger in the air indefinitely. These airborne chemicals can irritate the eyes and throat and have proven harmful to individuals with respiratory disorders.

Comparing the Advantages

Although you can use exterior paints indoors, they are only the second-best choice. At first glance, exterior paints may seem better indoors and out because they’re tough enough to hold up under challenging outdoor conditions. But indoor environments pose their own challenges that interior paints are better designed and equipped to deal with. Interior paints also offer some practical advantages to home decorators. For instance, most exterior paints are available in three finishes — flat, semigloss, and gloss-enamel. Still, interior paints may also be supplied in as many as six finishes, which include satin, eggshell, and matte.