Honeywell International filed a patent infringement suit against Nest Labs this morning, claiming Nest's new Learning Thermostat infringes several Honeywell patents. The lawsuit also aims at stopping Best Buy from selling the Nest thermostats through its stores. Including a retail seller like Best Buy in a case like this is a fairly common strategy used to choke off the supply going to the end consumer — US patent law allows a patent owner to go after those that "make, use, offer to sell, or sell" allegedly infringing products.

The patents at issue in the case are related to the operation and programming of thermostats, and include some interesting claim coverage. Take a look for yourself:

• U.S. Patent No. 7,634,504 - this patent was filed in 2006 (issued 2009) and covers displaying grammatically complete sentences while programming a thermostat.
• U.S. Patent No. 7,142,948 - this patent was filed in 2004 (issued 2006) and covers a thermostat figuring out and displaying how long it will take to get to a specific setting, like temperature. The Nest definitely has this feature; it's a main selling point of the device.
• U.S. Patent No. 7,584,899 - this patent was filed in 2006 (issued 2009) and covers a thermostat with a face movable (e.g., rotated or turned) around a central display. The display shows a change in a setting as the face is moved.
• U.S. Patent No. 7,159,789 - this patent was filed in 2004 (issued 2007) and covers a thermostat having a rotating selector, a potentiometer and a non-rotating element (like a display) on the front face. The non-rotating element is fixed to the thermostat housing with a support member offset relative to the rotating selector.
• U.S. Patent No. 7,159,790 - this patent was filed in 2004 (issued 2007) and covers a thermostat having two laterally-offset rotation axes. (The Nest doesn't have these, as far as we can tell — we'll see what Honeywell means by this.)
• U.S. Patent No. 7,476,988 - this patent was filed in 2005 (issued 2009) and covers a power stealing system that transfers power from the switch to a storage device when the switch is off, and powers the controller from a secondary power supply if the power at the storage device is insufficient.
• U.S. Patent No. 6,975,958 - this patent was filed in 2003 (issued 2005) and covers a method of controlling an environmental control system from a remote to adjust the settings of the system.

For its part, Honeywell has stated that "competition is good and we welcome it, but we will not stand by while competitors, large or small, offer products that infringe on our intellectual property."

We reached out to Nest, who told us that they "have not yet reviewed the actual filing, which we learned about this morning through Honeywell's press release. We will provide comment once we've had the opportunity to review it." We'll let you know as we hear more.