Though a well-built house can easily stand for well over a century, it's windows will need to be replaced at least once during that time. While this may seem like a massive undertaking, replacing windows is a simple task for crews who do this work every day.

When your home is in need of window replacement, you will see a combination of these five things:

1. Excessive Heating and Cooling Utility Bills

One of the first signs of failed window seals and unseen window damage is excessively high utility bills. As the windows in your home start to fail, your heating and cooling bills will continue to rise. If it is taking more power to cool and heat your house this year than last year, then you should look to the windows as a possible cause.

2. Fogged or Damaged Glass Panes

If your home has double-pane or triple-pane windows and they have moisture or dirt accumulated between the panes, this means their seals have failed. Since it is the gas between the panes that provides the window's insulation, cloudy, moist, or dirty glass panes is a sure sign the seals have failed and the windows are no longer insulated.

3. Leaking or Drafty Windows

If you stand next to a window on a hot or cold day, you should not feel a temperature difference from the middle of the room. If your rooms get hotter or colder as you approach the windows, this means they are transferring heat between the indoors and outdoors.

To test for leaks, light a candle and run the flame around the frames of your windows. When the flame flickers or is extinguished, there is a leak in the window causing a draft.

4. Window Hardware Malfunctions

If you've been complaining lately because your windows don't want to open correctly or their hardware is starting to break, then this is also a sign it is probably time to start thinking about replacing the windows.

5. Signs of Termites or Dry Rot Problems

Finally, sometimes windows fail around their frames rather than around the glass panes. This is especially common for windows made with wooden frames. When wood frame windows suffer from dry rot or termite damage, they will feel soft when you push around their frames with your hand. When you push around the windows they should not have any give at all. If you have spots where the window frames move, then dry rot or termite issues should be considered.