“All home automation is local.” Which is to say the architectural features of every building are somewhat different, and this definitely affects range.
For example, if your walls are cement, Adobe, brick, or contain foilbacked insulation or chicken wire lathing, then signal has a very hard time getting through. Even foil wallpaper is a problem. So sometimes you need to bounce the signal out through doorways and down the hall and around the corner, which you do just by placing repeating devices as needed.
You will find more discussion in the following two topics. Although you are working with zigbee devices the same concepts apply from the Z Wave discussions.
Typical distance for one hop in a home with plain wood walls would be about 40 feet for zigbee and about 60 feet for Z wave plus. But again if the signal hits an architectural barrier, it may just stop there.
One issue which is zigbee specific is that strong Wi-Fi can drown out zigbee signals. So the very first thing to do is to make sure that your smartthings hub is at least 3 m from your Wi-Fi router. Sometimes that’s all you need to do to improve zigbee communications.
You can also check and make sure that your Wi-Fi channel is as far away as possible from your zigbee channel.
