When the star Sirius appears in the night sky, it officially kicks off the "dog days of summer," 40 of the hottest, stickiest days of the year (from July 3rd to August 15th). With energy costs very high, now is an excellent time to beat the heat (and to beat high energy bills) by purchasing a new air-conditioning system. Today's high-efficiency models with a federal "energy star" designation use half the energy of a 20-year old model. And during peak cooling periods, you can cut overall energy bills 20 percent to 40 percent. Units 10-years-old or older have seasonal energy efficiency ratings (S.E.E.R.s) of only 6 to 8. New units are rated 12 or better -- a big difference and big savings. Also, many utilities now offer rebates on these units. And that's the On The House tip for today.