There is way to disable/enable SMS in your Android 4.4 Hangouts
As of version 2.0, the Google Hangouts app for Android can handle SMS messages as well as regular instant messages. When you start it up for the first time you’ll be asked if you want to use Hangouts for SMS or not. Tap yes and your existing messages are imported into the app, and you’ll receive future SMS notifications through Hangouts instead of your preloaded SMS app. Tap “Maybe later” and you’ll continue using your preloaded Messaging app.
But what if you’ve tried it and want out? Well, turns out there’s a simple way to disable SMS in Hangouts and go back to using the built-in app.
To disable SMS in Hangouts after you’ve enabled it — or enable it after you’ve chosen not to — head to:
- Menu Settings > SMS
- Under “General,” toggle “Turn on SMS” to enable or disable this feature.
- After disabling Hangouts your built-in SMS app (usually “Messages” or “Messaging” in the app drawer) will handle text messages.
Note: If you’re using a “stock” Android device like the Nexus 5, with Android 4.4 KitKat, you’ll see an “SMS Enabled” button instead of the option above. Tap that to go to “Wireless & networks” menu where you can select a default SMS app — choose between Hangouts and any third-party SMS app you might have downloaded from the Play Store.
Source Android Central