I've been there.
My first house was an adorable cape built in 1937. I think the only things in that house after 1937 were my husband and me. We replaced everything. The last thing - the windows.
Replacing windows is an expense - you'll get no argument from me. However, new windows are one of the wisest home investments you'll make either for your own enjoyment, or to help get your home sold. However, did you know that the direction your windows face can be a huge determining factor in your energy costs?
In North America, south-facing windows receive the most heat throughout the day, with north windows receiving the least. East and west facing windows will only endure a brief morning or evening sun.
While a south-facing room filled with windows might be appealing to a lazy cat stretched out on a sofa, the temperature can easily rise 10 degrees by afternoon. Room darkening shades are a must. Increased sunlight forces the air conditioner to work harder, raising energy costs (Almost 20 percent of the average home owner's utility bill is from cooling costs!)
Custom made window treatments don't have to send you to the poor house. Lowe's and Home Depot have top of the line products such as Hunter Douglas and Bali at reasonable prices and knowledgeable staff on hand to help. JC Penney also features a sale with significant savings a few times a year.
While it may seem like a lot of money to spend - the initial investment will save you many dollars over the years. Dollars you can save to buy some kitty toys for Fluffy, after she's done stretching out on the sofa.