A system that implements wireless communication with replay protection for lower power building control applications. In one example, a battery-powered device includes a counter value with each message transmitted to an always-on device. If the always-on device receive an invalid counter value, instead of sending back an acknowledgement, it sends back a message containing an updated counter value. The battery-powered device may keep its receiver on after sending a message for at least a period of time, the battery-powered device receives the message and updates its counter with the received updated counter value. Since it did not receive an acknowledgement, it retries its original message, this time with the updated counter value. The retry message is likely to be successfully transmitted.