Amazon Alexa voice control for Nest's Thermostat is live

The integration between Amazon's Alexa voice control system and Nest's Thermostat has gone live, allowing owners of the Echo, Fire TV, or other devices to control their heating by spoken command. Announced earlier this month, the functionality has gone live in the Alexa companion app, allowing users to link the smart HVAC control to their Amazon account.

Once that's done, Alexa – whether through the original Echo speaker, the Fire TV with the latest firmware, or either the new Echo Dot or tap – can take control over heating and cooling.

There's a fairly broad variety of actual commands you can issue, too, ranging from the general to the specific. On the one hand, if you're simply too hot or too cold, you can say "Alexa, lower the temperature" and Nest will automatically notch it down two degrees; the same works in reverse.

Alternatively, you can set a specific target temperature, such as asking "Alexa, set the temperature to 70 degrees." There are various different ways to phrase it, too, rather than forcing you to recall the exact command:

Alexa, lower the temperature by 4 degrees.

Alexa, cool down my "thermostat name" by 4 degrees.

Alexa, raise the "thermostat name" by 4 degrees.

Alexa, make my "thermostat name" warmer by 4 degrees.

Alexa, increase the "thermostat name" temperature by 4 degrees.

For those homes with multiple Nest thermostats – say, if you have one controlling the upstairs zone, and a second for downstairs – Alexa can individually manage them. That can be by specifying from the outset, such as saying "Alexa, turn my upstairs thermostat to 68 degrees," though Amazon's assistant will double-check for clarification if no thermostat name is given.

It's worth noting that there are some circumstances when Alexa can't take control. If the Nest is in Away mode, has switched to Auto-Away, or is turned off, voice commands won't be supported. Similarly, if Emergency Heat is being used, or if there's been an Emergency Shutoff, Alexa won't work.

For advanced users, various Alexa Skills – basically voice-controlled macros – are in the pipeline, too. For instance, you'll be able to tell Alexa you're leaving the house, and the temperature will automatically be lowered, or inform her that you're too cold and have the temperature increased.

Earlier in March, Google-owned Nest added better control over auto-away settings, allowing users' phones to be recognized by the thermostat so as to spot when people were around or if they had left.