How will I know when it's time to replace my insulated glass windows?

The surest sign that it’s time to replace your windows is when condensation appears on the glass when it’s humid outdoors and your air-conditioned home is nice and cool inside.

Fog and water droplets on the glass usually mean the window's interior seal has failed, and your air conditioner is having to work extra hard to cool your home. In our low-humidity climate, though, the signs aren’t so obvious.

Here is a checklist that will help you decide if you need to replace the windows in your home.

• Slowly wave a lit candle around the edges of your windows. If the flame flickers, it’s a signal that your windows are drafty. Drafts mean cool air is escaping from your home and hot air is getting in. It’s time to upgrade to more energy-efficient windows.
• Do you have to fight with your windows to open and close them? Rollers and guides will wear out over time.
• Can you hear too much outdoor noise when you're in the house? New windows with two panes of glass and energy-efficient air space in between help deaden the outdoor noise.
• Can you see daylight around the perimeter of the windows? That’s a sign of a broken seal and a loss of energy efficiency. Air that comes into or leaves the house through that breach can send your energy bills soaring.
• Are you sick of scraping, caulking, and painting your wood windows? Aluminum-clad wood windows let you change the paint color indoors, but they never need painting outdoors.
• Are you planning to sell your home? Low-maintenance, energy-efficient windows can be a selling point, and they can make your house look more attractive from the curb.
• Do they rattle when it is breezy outside?
• Do out dust storms leave a layer of dust on the windowsills?