Does Bubble Wrap Work as Window Insulation?

Bubble wrap is an effective and economical thermal insulator for windows that can reduce heat loss by up to 50%. Placing it over the glass creates an air chamber that acts as a barrier against cold in winter and heat in summer, without the need for complex construction work or installations.

How does bubble wrap work as an insulator?

Bubble wrap is made of polyethylene and contains sealed air cells. The air trapped inside each bubble is an excellent natural thermal insulator: it prevents heat transfer between the interior and exterior of the home.

By adhering the film to the window glass, a double air chamber is created (that of the bubbles + the one between the plastic and the glass) which slows down temperature exchange. This same principle is used by double-glazed windows, albeit on a smaller scale.

How to insulate windows with bubble wrap: step by step

1. Cut a piece of bubble wrap the same size as the window pane to be insulated.
2. Fill a spray bottle with clean water and apply a thin layer to the inside of the glass.
3. Place the plastic with the bubbles facing the glass (outwards). The water acts as a natural adhesive and keeps the film stuck without the need for tape.
4. Smooth with your hand to remove air bubbles between the glass and the film.
5. Trim any excess edges with a utility knife or scissors.

Bubble wrap as window insulation for home energy efficiency

Single or double bubble?

To insulate windows from the cold, you can use two types of bubble wrap:

• Single bubble: a single layer of bubbles. Sufficient for temperate climates and as a first thermal barrier.
• Double bubble: two overlapping layers of bubbles. Greater insulating capacity, recommended for areas with cold winters.

For even better results, there are versions with a reflective aluminum foil that enhances the insulating effect by reflecting radiant heat.

Advantages of bubble wrap as an insulator

• Economical: much cheaper than replacing windows or installing double glazing.
• Easy to install and remove: no tools needed and leaves no residue on the glass.
• Allows light through: the bubbles are translucent, so the room still receives natural light (although it loses some clarity).
• Sound insulation: in addition to cold, it dampens outside noise.
• Reusable: it can be removed in spring and put back on the following winter.

What other surfaces is it useful for?

In addition to windows, bubble wrap can be used as an insulator for:

• Greenhouses: protects plants from frost without blocking light.
• Attics and lofts: as an additional layer under the roof.
• Garage doors: glued to the interior panels, it reduces the entry of cold.
• Pots: wrapping pots protects roots from winter cold.