Turning dumb radiators into smart ones, the Eve Thermo simply replaces your old thermostatic radiator valves (TRVs) with ones that can be controlled via your smartphone. They look nice, are easy to control and integrate with Apple HomeKit. The lack of Android, Alexa or Google Assistant support will put off some people, while their inability to call for hot water makes this system less flexible than the competition.
- HomeKit integration
- Looks nice
- Simple to fit and use
- Can’t call for heat
- Basic scheduling
- No Android support
- UKRRP: £64.99
- IntegrationsWorks with Apple HomeKit only
- Radiator controlReplaces your existing TRV to deliver more precise temperature control
- BatteriesRuns off two AA batteries, which should last six to eight months
The problem with traditional smart thermostats is that you can only set a single target temperature, which inevitably leaves some rooms too hot and others too cool. Smart thermostatic radiator valves, such as the Eve Thermo, offer control over a single radiator, enabling you to keep each room at your ideal temperature.
Built for HomeKit, the Eve Thermo is a simple upgrade for practically any radiator; however, the lack of support for Alexa or the Google Assistant, and the inability to call for heat, may put off some people.
Design and Features
- HomeKit compatible
- Can replace most existing TRVs
- Basic scheduling
Eve has clearly spent time making the Thermo look good. With its soft-touch white finish, the Thermo is attractive when sat idle; but there’s an LCD screen hidden beneath the surface. The overall effect is that this is a more modern and nicely designed device than some of the competition, such as the TRVs used in the Honeywell Home Evohome.
Installation is easy. Just scan the HomeKit code from the Eve app or the Apple Home app (there’s no Android support) and follow the wizard to get the TRV up and running. The Thermo uses both Thread and Bluetooth for communication.
Thread support is great to see. This new low-power smart home protocol delivers better range than Bluetooth and is more robust, too. To use Thread, you need a Thread Border Router, such as the Apple HomePod Mini.
If you don’t have a Thread Border Router, the Eve Thermo defaults to its Bluetooth connection. If you want to remote control it, you’ll need an Apple Home Hub within the connection range. This can be a HomePod, Apple TV or even an iPad permanently plugged in.
Once the Eve Thermo is connected to your home, you can physically install it. Just remove the existing TRV from a radiator by unscrewing it, then screw the Thermo into place. There are adapters in the box that offer compatibility with the most common types of TRVs.
You can manually control the set temperature using the up/down arrows on the front of the Eve Thermo. You can move in half-degree increments, which allows you to turn down a room that’s too hot or turn up the temperature to give a cool room a boost. Changes last until the next change in the set schedule.
The Thermo is controllable from the Home app or the Eve app. From the Home app, you can set a target temperature, or turn the TRV on or off. You can use HomeKit Automations – say, for turning off the TRV when everyone leaves the home.
You can adjust temperature and turn the TRV off using the Eve app, but you can do more here. Schedules are a useful way to automatically control the desired temperature.
Schedules are formulated outside the TRV, so you can create the ones you want (living space, bedrooms and so on), and then set the Eve Thermo units to which they apply.
I found schedules easy to set but quite simplistic. Each one has a Comfort temperature (the setting you want when the room is occupied) and an Economy setting (a lower temperature for when you’re not in a room).
You then set the time periods that each temperature type applies. That makes things easy, but it removes the nuance that Honeywell Evohome or Tado provide. With either of those systems you could, for example, have your bedroom at a temperature of 20ºC for cold mornings, drop to 14ºC during the day when the room isn’t in use, and come on at a cooler 18ºC in the evening.
The other issue with schedules is that the Eve Thermo can’t call for heat. That is, it can’t tell the boiler to turn on. That means that the Thermo is only effective if your main thermostat is on and is requesting heat. It’s important to synchronise your Eve Thermo schedules with your main thermostat to work around this issue.
If you have an Eve Windows/Door sensor, you can link it to the Eve Thermo. When a door or window is opened, the connected Thermo will turn off automatically. After all, there’s no point heating a room if you’re letting the air escape.
Using a physical sensor makes the response faster, but it’s an extra expense. Both Tado (if you subscribe to the service) and Honeywell Evohome have an algorithm to detect open windows; when they measure that the temperature is dropping, they’ll shut down.
Voice control is provided by Siri but there’s no Amazon Alexa or Google Assistant support, which is a shame.
The biggest issue, as mentioned, is that the Eve Thermo can’t call for heat. Turning up the radiator valve in a cold room will have no effect if there’s no hot water being pumped around your system.
When you do have hot water, the Eve Thermo does a good job of regulating the temperature of that radiator. Using an external temperature sensor near the radiator, the Eve Thermo was always with 0.5ºC of my other reading.
There’s wider temperature variation across my test lab, although that’s the same for any room: you get warm and cool spots.
I found the thermostat fairly quiet in operation: you can hear the whirr of the motor adjusting the radiator valve, but it isn’t particularly intrusive. It’s something you’ll easily become used to.
Should you buy it?
If you use HomeKit for your smart home and want to upgrade dumb radiators into smart ones that will keep a room at your ideal temperature, the Eve Thermo are a good choice.
If you want radiator valves that can demand hot water, or a smart heating system that works outside of Apple, look elsewhere.
Without the ability to call for heat, the Eve Thermo isn’t quite as useful as its main competition, Honeywell Home Evohome and Tado. That doesn’t mean the Eve Thermo is useless. It’s a clear upgrade on a traditional TRV, giving fine control over the temperature you want.
Since the Eve Thermo is a separate system it will work alongside an existing thermostat, dumb or smart. For people renting, who aren’t allowed to upgrade boiler controls, it’s a way of adding some smarts to a home.
That said, the Tado Smart Radiator Thermostats can be run standalone without the boiler controls. Although you have to pay for a Tado Bridge and subscribe to the service to get the most energy-saving tools (you can just subscribe during the colder months), each radiator valve is cheaper and the system works with HomeKit, Alexa and the Google Assistant. And, you can upgrade to add the call for heat option.
That very much makes the Eve Thermo a product for those who are simply concerned with HomeKit support. For alternatives, check out my guide to the best smart thermostats.
How we test
Unlike other sites, we test every smart thermostat we review thoroughly over an extended period of time. We use standard tests to compare features properly. We’ll always tell you what we find. We never, ever, accept money to review a product.
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Used as our main smart thermostat for the review period
We monitor the temperature of our test lab to see how well the thermostat maintains temperature.
Smart thermostats are installed into our custom test set-up; smart radiator valves are installed on multiple radiators throughout our test lab.
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Thread is more robust than Bluetooth and offers better range, which makes devices easier to install and operate. You do need a Thread Border Router on your network to use this protocol.
No, it can’t tell your boiler to turn on and off.
It requires an additional sensor to tell the device that a window is open; this then turns the radiator off so that you’re not wasting energy trying to heat the outside.