Most people get confused when it comes to the sheen of paint. What adds to the confusion is that there are no standards for sheen from manufacture to manufacture. One companies flat might look similar to another companies eggshell or satin.
In general, sheen goes from flat to eggshell, satin, semi-gloss, and finally gloss. Some companies have high gloss.
In the residential market we are usually dealing with the first four. On interior walls it’s usually flat or eggshell and on exteriors it’s most often flat or satin.
When choosing a color and sheen for the exterior of your home, always pick a high quality product. By doing so you will ensure a long lasting finish (when the proper prep work has been done).
On the exterior of your home, the sheen you choose will effect how easy or difficult it will be to keep your home “clean” and a clean exterior will extend the life of your paint job. In simple terms, the less sheen you choose the more texture the surface of the paint will have. That “texture” holds dirt. Dirt and moisture over time will breakdown the paint film. A slicker feel, like satin will repel water and dirt better.
The number one enemy to the exterior of your home is the relentless Sun followed by the weather. Hot, cold, rain, hail, etc.
After you have had your home painted, there are two things you can do to keep your home looking good and prolong the life of your paint.
#1 Keep your exterior clean. Powerwash twice a year. This should be a relatively low power wash. No chemicals needed. Wash off cobwebs, dirt, etc.
#2 Quickly address any damage to the paint. Hail or animal damage for example. Any penetration into the paint film will allow the elements to get between the paint and your homes exterior and grow into a bigger problem.
I recommend choosing at least a satin sheen for exteriors. It will perform over time and it’s not so shiny as to look “funny” in your neighborhood. The smoother finish helps repel dirt and moisture and it’s easier to clean. One thing to bear in mind is that flat paint hides surface imperfections and as the sheen goes up, imperfections begin to become more noticeable. This may be an issue for older homes with a little more wear and tear on them.
If you like the look of a flat finish, choose a top quality product and be more diligent about keeping it clean. I had a satin finish on my own home for the last 15 years and just switched to flat. I just like the look better so in the end you should choose what you like the look of and be prepared to work a little to keep the exterior looking nice.