2.4GHz WiFi

• Pros - Building wide coverage. Lots of bandwidth.
• Cons - Mains power needed for most off-the-shelf low cost boards. Low power would need a custom build in all probability. Security is a concern unless upgrades to WiFi includes a segregated network for IoT devices.

433MHz RTL-SDR Compatible

• Pros - Many low cost temperature sensing remote units available. Operates for a very long time with AA batteries. Easy to integrate (e.g., OpenMQTTGateway).
• Cons - Tests confirm that path loss is a big issue. Would need multiple receivers and they almost certainly need mains power.

Zigbee

• Pros - Many low cost temperature sensing remote units available. Operates for a very long time with AA batteries. Easy to integrate (e.g., Home Assistant). Mesh network can cover a lot of area with repeaters/routers.
• Cons - Repeaters/routers need mains power. Potential interference from WiFi 2.4GHz radios disrupting transmissions.

LoRa

• Pros - Low power. Easy to integrate (e.g., OpenMQTTGateway). Very long range.
• Cons - Limited Off-the-shelf hardware satisfying the low power requirement.

All things being equal, Zigbee would be the best fit with the exception of the repeaters needing mains power. As a result, we are proceeding with LoRa as the wireless radio technology.