Last year I decided to sink some money into the house. I had a high-efficiency gas furnace installed to replace the one that was probably the original when the house was built in the early 80's. The main reason for the new furnace, however, was to get air conditioning as opposed to the old swamp cooler. Later in the year I had all of the windows replaced with high-efficiency ones to get in on that $1500 tax rebate. This month's utility bill should have been a good indicator as to whether the investment was a good one. So far, so good! My gas usage was down 10% from last year and that was during one of the coldest periods on record! Of course my electricity bills will be higher in summer as we'll be using the air conditioning instead of the swamp cooler, but the tradeoff will hopefully be slightly lower water bills. The big plus will be the comfort of being cool during the months with higher humidity.