Nest is introducing a new version of the Nest Thermostat today that has a bigger, higher-resolution display and a slimmer build. The thermostat otherwise hasn't changed much: it's still shaped like a hockey puck with a circular display in the center. That display is now supposed to be 40 percent bigger, which should give it close to a 2.5-inch diameter, with a resolution that puts its pixel density at 229 pixels per inch, up 25 percent over the last model. This is the Nest Thermostat's third iteration, with the last model announced almost three full years ago.

The new thermostat's bigger and sharper display is really its highlight feature, but it allows the thermostat to do a bit more, too. Nest says that the thermostat's display is now readable from across a room, and as such it'll start turning on whenever it detects that you're around. It can be set to show you the house's target temperature or just a clock, the latter of which seems a lot less useful. Aside from the display, the thermostat is also gaining the ability to detect overheating issues that may signal a need for furnace repair. That feature will also come to existing Nest Thermostats through a software update later this year.

As it's been saying for a while now, Nest is reiterating that the real selling point of the thermostat is that it should save you money in the long run, with heating costs dropping about 10 percent and cooling costs dropping closer to 15 percent. The new Nest Thermostat goes on sale today through Nest's website and Amazon, and it's supposed to hit Best Buy, Target, and home improvement stores in the future. It'll sell for $249, with the price of the second generation model dropping to $199 until it's sold out.

Left: Second generation. Right: Third generation.