If your electricity bill climbs every summer, a smart thermostat could help keep cooling costs in check. Amazon's Smart Thermostat is an excellent option, currently on sale for just £41 at Amazon as part of their early Prime Day promotion.

This Alexa-compatible thermostat can learn your routines and help you monitor energy use. For a device that costs under £80, it offers a lot of helpful features. One of its most useful is the ability to learn and adapt to your routines, reducing the need to constantly tweak the temperature yourself. It’s also compatible with most 24-volt HVAC systems, adjusting itself accordingly depending on whether you’re asleep or at home.

The app lets you create schedules and monitor energy usage as well, giving you a sense of how much AC you’re using so you can make adjustments before your next utility bill arrives. Plus, it’s particularly good if you’re embedded in Amazon's ecosystem. It’s compatible with Alexa, allowing you to adjust the temperature using voice commands or the mobile app.

You can also create Alexa Routines that work alongside other compatible smart home devices like the Amazon Smart Air Quality Monitor, setting up automations that adjust your home’s temperature when certain indoor air quality conditions are detected. So long as you’re fine going without native temperature sensors, this smart thermostat is an excellent value for the price.