Constantly rising energy costs and the predicted scarcity of energy resources make it all the more urgent to insulate our dwellings against heat loss during the winter and to keep them cooler in the summer months. A non-insulated home can loose a high percentage of heat, which not only costs the homeowner money, but requires additional energy to maintain a comfortable temperature zone, thereby increasing carbon dioxide emissions. While most of the newly constructed homes in France are adequately insulated during their construction, many of us have purchased older homes that may require adding insulation to make them more energy efficient. The types of insulating materials as well as techniques for applying them are quite varied, and the choice of what to use and how to install it will depend in large part on your home and how it was originally built.

There are products for insulating the exterior walls by placing insulating material to the outside of the walls or else thin layers of insulation on the inside. All of which requires a major investment and total change of appearance to the house. By far the most common way to increase the energy efficiency of your home is by adding insulation to the attic either on top of the ceiling joists or else in between the roofing rafters, or both. Basements, while not very common in France, should also have insulation in between the beams that support the floor above them.

The most common insulating material used in most home construction and readily available at any building materials centre is the ubiquitous yellow fibreglass that comes in either rolls or panels. However, there is an increasing market for more natural insulating materials that offer distinct advantages over fibreglass and especially over some of the chemical foam insulation that is sprayed on. The natural materials are all renewable resources, don’t require extensive processing in their manufacture and provide an excellent R factor of insulation. They include: hemp, lambs wool, cellulose fibres, wood fibres, bird feathers, cork, flax and even straw. Each of these natural materials has its own particular use in insulating a home, depending on the space to be insulated and the type of construction. One of the most efficient, easy to use and a bit more readily available than the others is hemp.

While almost impossible to find in the United States because of federals laws prohibiting even the growing of industrial hemp because of its resemblance to cannabis, hemp is increasingly used in Europe as an excellent alternative to fibreglass insulation. It can be found in loose form, in semi-rigid panels and in rolls, can be mixed with concrete to make a better insulated floor slab or exterior wall and can even be mixed with plaster for exterior walls. The advantages of using hemp insulation are many: it is an agricultural product and renewable resource; it provides excellent insulation against heat loss as well as noise (a 100 mm thick panel provides an R-5 insulating coefficient); it is recyclable and reusable (Have you ever tried to reuse old fibreglass insulation?); it is impervious to insects; it is non-toxic. The only drawbacks to using hemp over fibreglass are its cost and difficulty in finding it.

You won’t find hemp insulation at any of your normal building material outlets. At present, it is only available from speciality manufacturers and suppliers and has to be ordered and possibly shipped to your home. There are some excellent internet sites with information about where you can find it (see below). Prices vary somewhat according to the supplier. For example, semi-rigid panels 100 mm thick cost from 12 to 15 € per square metre. A packet of six panels that measure 1.2 metres by 0.6 metres each and will cover 4.32 square metres will cost roughly 60 € when the VAT has been included. While more expensive that fibreglass, installing natural insulating materials is a wise investment that will not only be better for your home, but also for the planet.

Roger Stevenson