Insulation

Polyisocyanurate foam, or polyiso for short, has the highest R-value per square inch: 6.5 to 6.8. Polyiso is a rigid foam that comes with a reflective foil on both sides to serve as a radiant barrier. Given its high R-value, rigid foam is usually meant for foundations and basement walls.

Caulking around a sill plate can be a good way to reduce drafts and heat loss through the small gaps between the sill plate and the foundation and between the sill plate and the framing lumber above, so it’s normally a good idea. If you’re having your sill plate replaced, ask your contractor to use a sealant between the foundation and the sill plate for the best results. If your sill plate is already installed, simply caulk the visible gaps on either side of the sill plate.

Spray foam insulation can last between 80 and 100 years, depending on the type. Closed-cell spray foam is more durable, while open-cell foam is more susceptible to moisture damage and deterioration. It's important to consult a professional installer to understand which type of foam will be used and its specific longevity. Additionally, be aware that some spray foams can damage plastic piping, so if you have PVC or CPVC pipes, discuss this with your installer.

A green home is one that focuses on conservation, with the goal often being net-zero carbon emissions and self-sustainability. It will often include some kind of self-generation equipment, like solar panels or a small wind turbine, high-efficiency electrical components and mechanicals, and high-quality insulation and air sealing to reduce the loss of conditioned air. Many green homes also include xeriscaping or rainwater collection to cut down on drainage and water consumption.