Nest launches slimmer, smarter learning thermostat

Startup Nest Labs is ready to launch the next generation of its connected learning thermostat. The device, which you can pre-order now and which ships in mid-October, is 20 percent slimmer than the original thermostat, and has new features that make it compatible with 95 percent of heating and cooling systems in the U.S.

Nest launched its original learning thermostat back in October of 2011 to much fanfare and it was immediately sold out for months. The device was designed by Nest CEO Tony Fadell, who was head designer of the iPhone and iPod for Apple (s AAPL), and the connected thermostat has smart algorithms that learn your habits and help you shave off 20 to 30 percent off of your energy bill. Fadell will be talking about the power of design to disrupt industries at our RoadMap conference on November 5 in San Francisco.

The first thing you’ll notice about the new Nest is that it has one moveable ring on its circumference as the physical interface. The previous ring design only took up part of the real estate of the circumference, and the other part didn’t move (see below). Making the ring all one piece makes the device slimmer and more clean looking.

The new Nest:

The first generation Nest:

As you can see, Nest also did away with the grill on the bottom of the face of the thermostat. They needed the grill for the occupancy (motion) sensors that can detect when people are nearby. But for the new thermostat design, Nest was able to switch the grill out with transparent, black plastic that still enables the sensors to “see.”

In addition to the hardware on the front, the back of the Nest is completely redesigned. The team made the circuit design circular to add more space, and Nest used that extra space to add two important new connectors: a spot for a wire called the Y2, which controls a second stage of AC, and the star connector, which enables new wires to control options like emergency heating and a whole home humidifier.

With these new wires, version 2 of thermostat is compatible with most types of heating and cooling systems, including forced air systems, radiant systems and heat pumps. Nest has included all types of new software functions that enable owners of these systems to cut energy in different ways.

The new Nest contains version 3 of its software — version 2 of the software was upgraded in April of this year. The new mobile software also is compatible with Android tablets like the Nexus 7 and Kindle Fire (GigaOM’s Kevin Tofel will like that: His in-depth review here).

The new Nest will cost the same as the original Nest: $250. The original Nest will be on sale for another couple of weeks and is being discounted down to $229 until supplies last.

Nest also updated me on its lawsuit with Honeywell (s HON). Back in February Honeywell slapped Nest with a patent infringement lawsuit over seven aspects of Nest’s smart thermostat technology. Nest tells me that the case is currently on hold, and Nest requested, and was granted a stay in the case. Nest also requested a re-examination of the original Honeywell patents in question, and Nest says 5 of the 7 Honeywell patent claims were accepted for reexamination, and those 5 patent claims were rejected.