External blinds are not uncommon in areas with strong sunlight and high heat, as they provide an added layer of insulation to the building and, in turn, can create a comfortable environment while using your air conditioning far less often. Blinds also protect against strong storms and wind damage to windows. When shopping for external blinds for a business of any sort, you might see that there are far more options than you realised. Note a few tips for making your choice.

Roller blinds versus slats

Roller blinds work like a roller door and cover the entire window when closed. You can adjust the height of roller blinds as needed, and they provide more protection against strong storms and wind damage than blinds with slats. The one solid piece of roller blinds also adds more protection against vandalism or break-ins, as it's virtually impossible to put a pry bar through the blinds and reach the window on the other side.

Blinds with slats can allow in more sunlight when you just want a bit of shade on the inside; these are good for restaurants and stores, where customers may not want to feel as if they're locked inside when you need to close the blinds. Roller blinds may also have more of an industrial than blinds with slats, and this too might be a consideration for businesses that need to attract customers to the front door.

Material

You can opt for wood or metal for roller blinds or those with slats; note that if you choose metal, this might be louder in very windy areas even if the blinds are closed and locked into position. If you want blinds that you only close at night for added security, metal might be a good option; for businesses open during the day, wood may absorb more sound and be much quieter. 

Wood will need more maintenance over the years than metal as it's more likely to fade in direct sunlight and may absorb moisture so it eventually chips and cracks. You will usually need to eventually have your wood blinds taken down and refinished.

Fabric exterior blinds can work in many cases where you simply want some protection from the sun, such as offices where there can be a glare on the computer screens. Be sure you note the opacity of fabric; this refers to how much light actually passes through the weave of the material. Dark fabrics with a loose weave may actually allow in more light than a lighter colour with a dense weave, so don't choose by colour alone.