Milesight LoRaWAN Thermostats Compared: WT101, WT102, WT201 and WT401

Last updated: 6 August 2026

Short answer: choose a LoRaWAN thermostat by what it has to switch, not by the room it sits in. Radiators with thermostatic valves take the WT101 (£59.85 ex VAT) or the battery-free WT102 (£97.26). Packaged heat pumps and PTACs wired for 24 V control take the WT201 (£97.26), and the split-design WT401 (£112.23) is the flexible retrofit option that avoids rewiring.

The reason estates get this wrong is that a LoRaWAN thermostat is sold as a temperature device when it is really a control device. Every LoRaWAN thermostat in the range measures temperature to roughly the same standard. What separates them is the actuator or relay on the other side, and if that does not match the plant, no amount of clever scheduling will help.

On this page:

• What does a LoRaWAN thermostat actually do?
• Which model controls which system?
• WT101 vs WT102: is battery-free worth the premium?
• The WT201 wiring caveat UK buyers should check first
• What does a LoRaWAN thermostat deployment cost?
• What you need besides the thermostat
• Frequently asked questions

What does a LoRaWAN thermostat actually do?

It reads room temperature, compares it against a schedule, and drives something: a valve, a relay, or a fan. The LoRaWAN part means it also reports what it is doing to a gateway, and accepts new setpoints and schedules back over the air, without a wire and without a Wi-Fi credential to manage.

That last point is why estates adopt this class of device. A traditional thermostatic radiator valve is a mechanical device that nobody can audit. A LoRaWAN thermostat replaces it with something that reports: what the room reached, when the valve opened, and whether anyone overrode it, across hundreds of rooms, from one dashboard. Our guide to IoT energy monitoring for commercial buildings covers how that data feeds a wider energy strategy.

All five LoRaWAN thermostat models share the same radio approach and the same broad sensing accuracy. The WT101 uses an NTC sensor rated ±0.5°C between 0°C and 50°C; the WT401 is quoted at a typical ±0.2°C and a maximum ±0.5°C. In a building context those are equivalent. Do not pick a LoRaWAN thermostat on sensing accuracy.

Which model controls which system?

Map the LoRaWAN thermostat to the actuator, in this order. Specifications below come from Milesight’s published product pages, and prices are live UK stock, ex VAT.

• WT101 — a stepping-motor head that replaces a thermostatic radiator valve. Fits M30 × 1.5 mm as standard with optional RA, RAV, RAVL, Giacomini and M28 adapters. Two 1.5 V Li-FeS2 AA cells, IP30, Ø52 × 90 mm. £59.85.
• WT102 — the same radiator valve job, but self-powered by temperature difference with no battery replacement required. Supports an external NTC probe or pairing with a WT401 for room sensing, plus NFC configuration and FUOTA firmware updates. £97.26.
• WT201 — a wall thermostat with relay terminals for staged plant: furnaces and air conditioners (2H/2C), heat pumps (4H/2C plus one stage auxiliary heat), boilers and PTAC. 24 VAC supply, 4.2-inch LCD, 113 × 110 × 21 mm. £97.26.
• WT401 — a split-unit design aimed at PTACs, mini splits and radiator valves, supporting BLE, LoRaWAN and Powerbus, and powered four ways: two ER14505 cells, 24 V AC/DC, 5 V USB-C, or Powerbus. 2.7-inch e-ink screen. £112.23.

Notice that two models cost exactly the same. The WT102 and WT201 are both £97.26 and they do entirely different jobs, which is the clearest possible illustration that price is not the axis to choose on here.

WT101 vs WT102: is battery-free worth the premium?

At estate scale, usually yes, and the deciding factor is access rather than energy. As a LoRaWAN thermostat the WT102 costs £37.41 more than the WT101. Across 200 radiators that is £7,482 of extra capital, which is a real number that needs justifying.

Here is what justifies it. The WT101 runs on two AA lithium cells, and Milesight quotes approximately eight years at SF7 on EU868, falling to five years at SF10, based on 10-minute intervals with monthly control across a five-month heating season. Those two numbers matter more than the headline. SF7 is a strong signal close to the gateway; SF10 is what a radiator in a basement corridor or behind a steel riser will actually see. Weak signal costs you three years of battery life.

The WT102 removes that variable entirely by harvesting energy from the temperature difference across the radiator valve. There is no cell to specify, no disposal route to arrange, and no need to book access to 200 rooms in a school or a hospital ward to change batteries. If your estate has rooms that are hard to enter during term time or clinical hours, the WT102 premium buys away a recurring access problem rather than a battery cost.

The honest counter-case: for a 20-radiator office with a gateway on the same floor, the WT101 at SF7 will run most of a decade and the £748 saved is better spent elsewhere. Our post on smart radiator retrofits for UK schools and NHS estates covers the wider retrofit case.

The WT201 wiring caveat UK buyers should check first

Check the control voltage before you order a WT201. Its terminal list reads RC, RH, C, W1, W2/AUX, E, Y1, Y2/GL, G, O/B, PEK, DI and GND, and it is powered at 24 VAC. That is the North American low-voltage HVAC control convention.

Plenty of UK plant does use it: packaged terminal air conditioners, many heat pump and VRF interfaces, and imported rooftop units. Plenty does not. A domestic-style combi boiler on a 230 V switched-live loop is not a WT201 application, and neither is a system where the only interface is a volt-free contact expecting mains switching. Before this LoRaWAN thermostat gets specified, open the existing controller and confirm there is a 24 V transformer and an R, C and W arrangement behind it.

Where the plant does not match, the WT401 is usually the answer. Its split design and four power options, including a plain USB-C 5 V feed, mean it can sit on the wall as the room interface while a separate controller does the switching. Milesight positions this LoRaWAN thermostat for wire-free installation in retrofit projects, which is exactly the constraint most UK buildings present.

What does a LoRaWAN thermostat deployment cost?

Hardware is easy to price; the gateway count is what moves the budget. Take a 200-radiator secondary school as a worked example, using live UK prices ex VAT.

Two hundred WT101 heads come to £11,970. The same count in WT102 comes to £19,452, a difference of £7,482. Add gateways: a UG65 at £279.82 covers a building, and a large or steel-framed school will want two or three rather than one, so call it £559.64 to £839.46. That puts a WT101 scheme at roughly £12,530 to £12,810 of hardware and a WT102 scheme at roughly £20,010 to £20,290.

Two costs are deliberately absent from those figures because they vary too much to publish honestly: installation labour, and whatever platform you put above the network server. If you run the embedded server inside the gateway, the second is zero. Ask any supplier quoting you a LoRaWAN thermostat scheme to separate hardware, labour and recurring software, because a single blended figure hides the only line that repeats every year.

The sizing rule worth remembering is that thermostat count drives the sensor line and building geometry drives the gateway line, and the two are independent. Doubling the radiators does not double the gateways.

What you need besides the thermostat

Every LoRaWAN thermostat needs a gateway in radio range and a network server to decode traffic and push schedules back. For a single building the cheapest complete path is a gateway with an embedded network server, because it removes any platform subscription.

The UG65 (£279.82) and UG67 (£658.39) both carry an embedded server. The UG63 (£98.76) is a packet forwarder and expects an external server, which is a common and expensive surprise. Our Milesight gateway buyer’s guide covers the choice properly, and our LoRaWAN primer explains the radio side.

One planning note specific to heating control. Because the WT101’s battery life depends heavily on spreading factor, gateway placement is not just a coverage question on a radiator retrofit, it is a LoRaWAN thermostat maintenance-cost question. Put the gateway where the furthest radiators still reach it at a low spreading factor.

Frequently asked questions

Will a LoRaWAN thermostat fit my existing radiator valves?

The WT101 and WT102 fit an M30 × 1.5 mm valve body as standard, with optional adapters for RA, RAV, RAVL, Giacomini and M28 bodies covering Comap, Herz and TA valves. Identify the valve body before ordering, because the adapter is not universal.

Can I run a LoRaWAN thermostat without a subscription?

Yes. A Milesight gateway with an embedded network server, such as the UG65 or UG67, can run the devices with no recurring platform fee. You only need a paid platform if you want dashboards, analytics or integration beyond what the gateway provides.

Does the WT102 really never need a battery?

Milesight states the WT102 is self-powered by temperature difference with no battery replacement required. That depends on there being a temperature difference to harvest, so it suits radiators in active heating service rather than valves that sit closed all year.

What temperature range can a LoRaWAN thermostat control to?

The WT101 and WT401 sense across −20°C to +60°C, which comfortably covers any occupied building setpoint.

Can I update firmware across a whole site at once?

The WT102 supports FUOTA firmware updates over the air and multicast bulk control, so schedules and firmware can be pushed to a group rather than device by device. That matters once you are past a few dozen units.

Is a LoRaWAN thermostat secure enough for a public-sector estate?

LoRaWAN encrypts payloads end to end between device and network server using AES-128 session keys, and these devices hold no building credentials the way a Wi-Fi thermostat does. The bigger control question is who can change setpoints in your platform, not the radio.

The bottom line

Survey the actuator first: valve body for radiators, control voltage for packaged plant. That single afternoon of work picks the right LoRaWAN thermostat for you. Spend the extra on the WT102 where room access is expensive or signal is weak, and take the WT101 where the gateway is close and rooms are easy to reach. Prices above are live UK stock ex VAT — browse the Milesight range, or send us a plant schedule and we will spec the mix and quote within one working day.