I heard a new noise the other night when I was in the garage. I was getting used to all the little electrical noises, but this time I heard a "shhhhhhhhhhh" sound from the front. Somewhat like what you'd hear letting air out of your tire. Then right after that, was the typical little electric motor sound. Each noise was about 2 to 3 seconds long.

Two climate control systems, one inside and the other at the tailpipe.

2007 Camry Hybrid (in service June 2006)
FE: 6.77L/100km (34.8 mpg) over 37750km (23450mi)
75% city - Ave trip 20 min - 2 Winters