This means examining buildings as they are built, and after they are built, to make certain they are running as efficiently as possible.
It's cheap. A 2004 government study indicated that for 27 cents per square foot commercial landlords can save 15% on their energy costs, getting the investment back in under 9 months.
Commissioning new buildings costs more, $1 per square foot, but the investment still pays for itself in under five years.
Not only that but the total carbon emissions saved through commissioning dwarfs other, less cost-effective steps, like managing the methane output from coal mining, or improving the efficiency of air conditioners.
Evan Mills, chief investigator for Berkeley National Laboratory at UC-Berkeley, maintains a hall of shame on his Web site, identifying the kinds of things you're looking for. The picture is from that page, showing the damage from moisture getting trapped inside a building. Fix it and save.
A new study indicates those 2004 costs may have been slightly overestimated, the return on investment slightly underestimated. States that have worked on energy efficiency, like California, have seen their per-capita use of electricity level off while it has risen 60% elsewhere.
The Building Commissioning Association offers some templates of how this works, but it's mainly a process of inspecting your heating and air conditioning systems, measuring their flow rates, calibrating sensors, and making certain everything works as it is supposed to. You also want to check shades, glazing, check for air leakage -- make certain the building materials meet the claims of their makers.
Right now, with so many millions of square feet of commercial space about to be foreclosed, is the exact right time to be doing this. If you save on operating costs you can lower your rents and still make money, or at least make an argument for renegotiating your lending agreements if market rents remain below operating costs.
Commissioning existing structures, then, makes all kinds of sense. You can save money on operations, you can get your rates to market without losing your shirt, you may stem foreclosure, and you're picking the lowest-hanging fruit on the green energy tree.