Most smart thermostats (Ecobee, Nest, Honeywell T9, Sensi) integrate natively with both Google Home and Alexa. Setup takes 5 minutes: enable the skill, log in, link the thermostat.

Useful voice commands: ‘Set thermostat to 75’, ‘What’s the indoor humidity?’, ‘Turn on AC schedule.’ Most useful at night when you don’t want to leave bed.