As you know, I've been doing residential energy audits for clients, and since I cannot do every one's house, I thought I'd hi-light different lessons I've learned from each.
The client owns a 2 story, 4 bedroom, 3 bathroom home built in 1997. I did the full energy audit, measured various appliances with my Kill-A-Watt meter and then sat down with the home owner. I've found that spending time to hear about how the family actually uses their house is vital.
I wrote up a list of areas for improvement, but one of the most glaring (& easy) ways to improve energy efficiency was to use some common sense.
1. Replace vestibule light that is left on when away (and is connected to outdoor lights on motion sensors) with a CFL.
2. Stop using the 6 bulb vanity mirror bathroom switch when using the upstairs bathroom. Instead use the single light (it is more than sufficient for most activities). (The owner ended up putting painter's tape on the switch to remind her not to flip it.)
3. Close the upstairs bedroom doors (currently used as offices) to utilize the heat the computers generate.
4. Replace the dirty air filters in the furnace.
Pretty boring I know. But the boring things are often what will make the biggest difference.