When it comes to the thermal performance of insulation, it is important to select a good product and then make sure it is properly installed. A fiberglass batt may be rated at R30 but if it is poorly installed, it may perform at R5, or not at all. For batt insulation to perform effectively, it needs to touch all six sides of the space it is installed in and there can be no gaps or voids. Other kinds of insulation, like blown-in cellulose, are more easily installed to maximize performance.
In addition to thermal performance, there are other considerations when selecting insulation. Some types contain toxins or have a high global warming potential because their production releases powerful greenhouse gases. Other types, such as cellulose insulation, can sequester carbon and have a negative carbon footprint. In this home, we employed high R value cellulose insulation on the interior as well as a rigid layer on the exterior, significantly increasing energy efficiency and reducing waste and cost.