Thermostats are dull aren't they? But they do control half of the money that you fork out every year on energy, so it pays to have a good one. And by good one we, of course, mean one that looks like HAL from 2001: A Space Odyssey.

Unlike HAL though, the Nest learning thermostat isn't out to kill you and keep your home for itself; but to learn your living habits so it can save you a few quid on your heating bill.

The Nest is a clever thermostat you see; over the course of a week it learns roughly when you like to have the heating on, how long for and at what temperature. As time goes on it becomes even more intuitive, such as picking up patterns like everyone leaving the house between 7.15 and 8.35 on a Wednesday, people having a lie-in on a Saturday morning and no-one being at home every other Friday.

Basically, like HAL, it studies you from afar, noting every little detail of your life and your daily habits. Unlike HAL, it does this for your own good though... we think.

It's connected up to Wi-Fi, so knows what the weather is like outside (using online forecasts) and has a 150-degree sensor so it knows if anyone is home. You can also set it from afar using a web-based portal or mobile apps.

It's also designed to be eco friendly too, awarding you a green leaf should you make a change that will benefit Mother Earth. A 1-degree difference can reduce energy use up to 5 per cent, so precision is important.

The Nest chaps at CES told us that it is as easy to fit as a light-fitting and it costs $249 Stateside. That may sound a lot for a thermostat, but we're told it will save you $173 per year, so you'll be breaking even after around 18 months. Over 3 years you'll have saved about $520.

That's if HAL, sorry Nest, hasn't plotted your downfall by then.

It's US only for now, we'll let you know if it hits this side of the pond anytime soon.