Will voice activated control still work if I lose my Wi-Fi connection?

No, the voice activated control functionality will not operate without Wi-Fi. A notification of non-connectivity to the voice server will be provided in an audio response message. You must also remain connected to Wi-Fi to receive automatic software product updates for voice control. If your received Wi-Fi signal strength is low on your thermostat, you may want to consider installing a Wi-Fi range extender for your home. Honeywell has tested with, and recommends this model (Linksys N300 Wi-Fi Range Extender).