You have three simple options.
First, if it has to be zwave, you can buy a Z wave touchpad deadbolt lock and embed it in the wall of the garage. So it’s not actually unlocking anything, it’s just transmitting the code. That works fine, it’s nicely weatherproof, most people like the looks, it’s just that it’s an expensive solution.
The new qkwikset obsidian lock has been Z wave certified and is due to start selling soon and would be pretty much perfect for this.
http://www.kwikset.com/obsidian
Or if you don’t want to wait, the Yale Assure is another option. Just make sure you get the Z wave model, not the Bluetooth.
https://www.amazon.com/dp/B00GPP33LW/
There are less expensive versions as well, I just happen to like the looks of both of those. But basically you just pick any deadbolt that you like and don’t use the deadbolt part.
- if you’re willing to use zigbee instead of zwave, The centralite 3400 model ( sold under both the Xfinity and Lowes iris brand names) works well with SmartThings as long as you use a custom device handler that is available in the community. It’s very popular and should cost under $50. Sometimes much less at your local Lowes. But it’s not as weatherproof.
https://www.amazon.com/Iris-Smart-Home-Management-3405-L1/dp/B01GCKAFX8/
- since I first wrote this, a Z wave keypad has come on the US market which works with SmartThings with a custom device type handler. Again, it’s not particularly weatherproof, so you’d want to put it inside a protective box. But it’s another option.
It’s manufactured by BEnext, but also sold under the Zipato name.
US version:
EU version:
DTH: