As is often the case, it depends. There are many factors to consider, and a lot of options available to cover the many different use cases around.
Range
DigiKey suggest that you can expect the following ranges for common IoT protocols in an unobstructed environment with little interference:
- 5 GHz Wi-Fi: 50 m
- ZigBee/RF4CE: 100 m
- Bluetooth low energy: 100 m
- 2.4 GHz Wi-Fi: 150 m
- Bluetooth low energy using Bluetooth 5 extended range capability: 200 to 400 m (depending on forward error correction coding scheme)
In most environments, you will not achieve this range, so adding extra 'headroom' would be a useful idea to guarantee that even in harsher environments, you still meet your requirements.
Power Consumption
The format of the data you're sending is going to really determine which protocol you want, given that many options meet your range criteria.
Wi-Fi, for example, is designed to carry relatively large amounts of data at once, with throughput as a design priority. As such, frequent, small packets are poorly suited to Wi-Fi (that said, Wi-Fi HaLow may be worthy of further investigation, as it's specifically designed for long range, low power operation).
Part two of the linked DigiKey article has some benchmarks on power consumption which are quite helpful:
Bluetooth low energy
Power consumption = 24 μA x 3 volts = 72 microwatts (µW)
Bits per second (in typical sensor operation) = 960
Energy per bit = 72 µW/960 bit/s = 75 nanojoules (nJ)/bit
ZigBee
Power consumption = 30 mA x 3 V = 90 milliwatts (mW)
Bits per second (at maximum raw data throughput) = 250,000
Energy per bit = 90 mW/250,000 bit/s = 360 nJ/bit
Wi-Fi
Power consumption = 116 mA x 1.8 V = 0.210 W
Bits per second = 40 million
Energy per bit = 0.210 W/40 Mbits/s = 5.25 nJ/bit
I was keen to emphasise considering the size of your data earlier because the 'energy per bit' statistic is very deceiving if only a tiny fraction of the bits you send are your payload (as might be the case with Wi-Fi). It may be worth looking up benchmarks for packets on the order of the size you'll be sending; you'll find hundreds online which might help inform your decision, such as TI's Bluetooth low energy power calculation tool.
Gateways & Compatibility
Obviously, you wouldn't need a gateway if you chose Wi-Fi, but often the power constraints make other options necessary, in which case a gateway is generally needed.
Consider if your users are likely to have a gateway. For example, home automators might already have a 'smart hub' (these typically support ZigBee and Z-Wave along with Wi-Fi devices). In that case, they might not need another gateway, in which case it would be favourable to use one of the more commonly supported protocols. That said, some smartphones support BLE natively, which could potentially be useful in some cases—you'll have to decide whether it's useful for you.
While I can't tell you one or the other (likely several protocols would fit to varying degrees), this should give you plenty to consider and inform your decision more effectively. I might personally go for BLE from what you've specified, but it's a rather arbitrary choice; many of the other protocols I've listed would work just fine too.
