As a thermostat installer, I've used BlueLinkSmartConnect on several installations. When there is power to the thermostat, the registration works great. If no power, BlueLinkSmartConnect will never see a thermostat to register. You need to make sure the installer has hooked up a "common" wire on the thermostat. With the stat powered, the registration works. If you need more help, click on the developers web site in BlueLinkSmartConnect store, and it will show you an 800 number. You can also send them an email. Once you register, the ease of setting up your schedule and seeing everything from your home screen makes it all worth it.