Combine windows with low-E glass facing south or southwest, homes that are close together with vinyl siding, and the sun and you get a recipe for melting siding. In case you aren't familiar with them, low-E (a.k.a. low-emittance) windows have a coating on them that suppresses radiative heat flow. In other words, it prevents heat from going where we don't want it to go. The amount of low-E and it's location on the glass is dependent on the climate the home is in. These windows are becoming more common as people seek to improve the energy performance of their homes.
In this video, we talk about the causes associated with the melting siding, how to prevent it in new construction, and we give tips for resolving the issues in existing homes. If you are planning on replacing your windows or are building a new home, you should familiarize yourself with the melting siding phenomenon.