Heating, air conditioning and ventilation account for 32 percent of the energy consumed in commercial buildings and lighting consumes another 25 percent, according to the 2008 Buildings Energy Data Book. Cypress Envirosystems and Adura Technologies are going to work together to reduce it.

Cypress, a division of Cypress Semiconductor, has developed a radio controlled thermostat that can replace the pneumatic thermostats deployed in most buildings built before 1995.

"You can't control them [pneumatic thermostats] remotely," said Harry Sim, CEO of Cypress Envirosystems. "They are compressed air."

Cypress' thermostat costs about $500 and installs in a few minutes. Google, Kaiser Permanente and Stanford have all installed the thermostats. (You need a single thermostat for roughly every 1,000 square feet of floor space, said Sim.)

Adura, funded by VantagePoint Venture Partners, has devised a controller for lighting systems. In tests with PG&E, Adura managed to cut power going to lights in a building by over 72 percent.

By combining together, the two companies say they can cut building power consumption by 30 percent to 50 percent. Cypress will sell Adura's equipment and vice versa. Over time, the two companies will try to synchronize their software so that it comes across more as a seamless solution. The technology from Cypress and Adura also work with the building management systems from incumbents like Johnson Controls and Honeywell.

Along with energy efficiency retrofits, building management has turned into a growth market in the past few years. Both the Federal government and the state of California have already passed initiatives to ensure that new commercial buildings will be net-zero energy structures by 2030. While solar will provide power, a substantial portion of the net-zero goal will be accomplished through clever conservation.

And each building adds up. Sim noted that California's baseline power requirement is around 35,000 gigawatts and the peak power requirement is around 55,000 gigawatts. That 20,000-gigawatt gap between baseline and peak is largely consumed by air conditioners flipping on on a hot summer day.

A company called Soladigm has raised about $20.66 million in equity, though how the company plans to use it is a mystery.

The Milpitas, Calif.-based startup raised the money from Khosla Ventures and Sigma Partners after offering to sell $21.6 million of its shares, according to its Oct. 1 filing with the U.S. Securities and Exchange Commission.

The company was incorporated in 2007, but its website says nothing about its products. Soladigm hints only that it's working on "green building solutions" that involve glass, optical coatings and semiconductors.

"Green building" is a term that means a whole lot of things, of course. Adding solar panels or using building materials that take less energy to produce than conventional components all can qualify.

Soladigm was founded by Paul Nguyen to develop windows embedded with electrochromic devices, according to his LinkedIn page. The company was previously called Echromics and based in Santa Rosa, Calif.

Electrochromic devices can change the colors of the windows and thus controls the amount of sunlight that passes through when receiving an electrical current. The technology could help cool a building.

Soladigm has raised several rounds of money this year. Aside from the $20.66 million equity round, the company also raised about $1 million in the form of equity, debt and warrants/options, according to a SEC filing last month. Back in June, a SEC filing said the company had raised $2 million in debt and warrants/options.

The SEC filings list Rao Mulpuri as a company executive. Mulpuri's LinkedIn profile says he's the CEO. He was previously the president of Novellus Systems Japan, a maker of semiconductor factory equipment. 

SAN FRANCISCO -- One you can take in the rain. One you can't.

Free Design Clinic, a group of architects trying to promote creative recycling, have one of the more interesting exhibits at West Coast Green, the big environmental building and decorating show taking place in San Francisco this week. The group takes household garbage and makes it useful. There are a few herb gardens constructed out of plastic water bottles.

The thing in the center of the picture is a yurt constructed from hyperextented umbrellas. On hot days, people gather under it, said Jason Harm, a member of Free Design. (In his spare time, he works for a national architecture firm – recently he worked on a new stadium in Dallas.) Don't stand up too quickly, however. You can get poked.

In the background is a pile of old cardboard tubes screwed together to form a chair. It supported both Jason and I at the same time (it's big enough for two). It was actually quite comfortable.

If you have a green building startup, here's a name you will want to remember: Pegasus Capital Advisors.

The private equity firm, which manages about $2 billion and has been around for over a decade, wants to put more money into energy and in particular into energy efficiency, i.e. light emitting diodes, green building materials, building control technologies. Like most private equity firms, a significant portion of the money will likely go into established, but listing, companies but it will also invest in new ventures through a subsidiary called Pegasus Sustainable Century.

The fund was founded by Craig Cogut, who came out of Drexel Burnham (bit of '80s trivia for you). The list of advisers is somewhat interesting. It includes Terry Tamminen, who headed up the California Environmental Protection Agency; Dan Kammen, one of UC Berkeley's star energy professors; George Shultz, the former Secretary of State; Marc Porat, founder of Serious Materials and Calstar Products; and Patrick Atkins, an expert on efficiently producing metals. And there's also Arik Arad, who ran security for El Al at Ben Gurion Airport Israel. Security is another area of focus for the firm.

Some of the investments include Fiberon, a composite decking material, and Molycorp Materials, which mines rare earth metals at the Mountain Pass Mine in California. Some of these get used in hybrid batteries.

Zeta Communities, which wants to build affordable, net-zero energy homes, opened its first factory in Sacramento today, a 91,000 square foot facility that could eventually employ 200.

The factory will be capable of churning out about 300 to 400 homes annually. Ultimately, Zeta would like to open 15 factories, geographically dispersed across the country, over the next five to seven years.

The company has already erected a model home in Oakland – see video here. Some of the features of the home include wraparound foam insulation for keeping heat in, a device that sucks heat out of water going down the drain and returns the heat to the water heater, solar panels, a screen that tells you how much energy you're consuming, and a computer-controlled skylight that can cool the house by circulating outside air. Plus, it looks pretty cool.

Unlike regular homes, modular homes are assembled in factories and then trucked out to the foundation where they will sit. Building in the factory allows carpenters to get a tighter seal on corners, thus preventing moisture and mold. Although modular homes haven't been huge hits in the U.S. yet, modular is a popular construction technique in Japan and Europe. It is expected to grow here. Zeta's goal is to eliminate any cost premium on modular homes while drastically reducing a homeowner's energy costs.

Still, it's not an easy business. Earlier this year, Michelle Kaufmann Designs, one of the early modular companies, called it quits.

Zeta is one of the green building companies incubated by Marc Porat. (Zeta's CEO is his sister.) Other companies include Serious Materials and CalStar Products, which makes green cement and bricks.

Masdar City, the futuristic green metropolis being built in Abu Dhabi, has selected BASF to be its preferred supplier for building materials.

BASF – familiar to middle aged Americans as a supplier of blank cassette tapes – is one of the world's big chemical and materials suppliers. Among its various building products are polystyrene insulation and chemicals for phase-change air conditioning.

Phase-change air conditioners essentially carry heat out of a room with the assistance of chemicals. The chemicals absorb energy (i.e., heat) in a room and in the process turn into a gas. The chemicals are then cycled through a series of pipes. The energy is dissipated, the gas turns into a solid, liquid or gel, and then re-enters the room that needs cooling. NREL has been testing this out for a while. Air conditioning can account for close to 70 percent of energy demand in hot locales like Abu Dhabi and nearby Dubai.

Phase-change materials could also conceivably be put into flooring and other materials.

Does the announcement mean that BASF gets every Masdar contract? No, but an inside track isn't bad. Abu Dhabi plans to spend billions on its various Masdar projects. Other ones include campuses created by NYU and MIT.

The emirate both wants to show how green construction can reduce energy demand through these projects, but also try to create local businesses that can compete in the new energy market.

Getting the tax credit for solar is comparatively easy. You call up an installer, they put solar panels on your roof, and then installer then files the paperwork for your credit.

The federal tax credit for home retrofits – which covers 30 percent of the cost of retrofit equipment in your home up to $1,500 – is a little more complex. Not all windows and doors quality for the credit and the credit only applies to things purchased, not installation costs.

To help out a little, Andersen Windows has come up with this website to guide consumers on what sort of products qualify. Naturally, it only includes their windows, but what do you want? If anything, it's a start. (San Francisco is also trying to put together a program to finance green retrofits through property tax surcharges.)

Besides, the window giant certainly has a wide selection. It currently is touting its 100 series windows, which come in frames made from Fibrex. Fibrex consists of 60 percent polymer and 40 percent sawdust and wood scraps.

Green buildings and building materials will likely play prominent roles in reducing energy consumption. Building operations consume approximately 40 percent of the energy in the U.S. and 76 percent of the electricity and much of this power consumed by buildings is not used efficiently. Luckily, as Dan Geiger of the Northern California chapter of the U.S. Green Building Council among others has pointed out, building performance can likely be improved somewhat economically.