I am a commercial landlord and own a bunch of wal-mart sized industrial buildings. One of my tenants calls me and tells me their electric bill is way higher than it should be. Like $1,200/month and would probably realistically expect it to be $500-$700/month. So I put together my investigative team (which is the HVAC guy, the electric guy, and my facility manager) and we go do a tour of the building. The sprinkler room is outside, by itself. Rather poor shape, cinder block, not insulated with holes to the outside (you can see through the block at places). I haven't been in this room in probably 4 years. Open the door. Instant Sauna. WTF??? So hanging inside is a 5KW electric heater. HVAC guy walks over and turns the thermostat, nothing. "Thermostat is broke, it's running full bore." So roughly 120 KW per day, 30 days a month, 3,600 KW wasted per month. We pulled out the old bills and this was broke at least a year, maybe a couple of years. Doh! Guess we figured out why the bill was so high. Good news is for about $10k we figured out how to lower our annual operating costs by about $15k/year. As our company grows I really don't know how the large companies do it. There are so many small important parts that you have to pay attention to.