It can be hard to determine when you need to replace your windows and when it is OK to repair them. Replacing old windows is a great thing for energy efficiency and resale value but can be a costly process. Below we will outline some questions that you can use to determine if it is time to replace your windows instead of just repairing them.
First, are the window sashes jammed or rotting? This sort of decay can be more than can be repaired. If water can penetrate the jam you should look into replacing the windows. If you are seeing condensation between the panes you may also need to place the window, this may be a warranty claim so check with the manufacturer.
Second, are you feeling drafts or worried about energy-efficiency? Energy efficient windows are a great for keeping your air conditioning in and the heat out. Caulking is also a great way to help reduce drafts. Weather stripping may also help. Unfortunately, caulking and weather stripping can only do so much. If you feel like you are not getting the energy efficiency you need you should consult with an installer to see what they can accomplish by adding new windows.
Finally, what if your windows are painted shut? Windows that are painted shut are generally pretty weather tight which is a great benefit but during the summer you cannot open these windows for airflow which is less than ideal. You may need to use a sash saw to cut the paint. You will need to be careful if the house was built before 1978 because of the risk of lead paint.
In the end, the need to replace windows depends a lot on what you are trying to achieve and the current state of your windows. Contacting a professional is the best way to see if you need new windows for your home.