When you’re choosing a high-efficiency wall system, you may want to also consider:
Total cost: This includes both the cost of the materials and the labor (time) to install it. Some systems, like structural insulated panels or insulated concrete forms, incorporate both structure and insulation. With other systems, you’ll have to factor in the additional cost of adding insulation after the structure is built.
Ease of construction: Are you planning on doing the construction yourself, or hiring it out? If you’re hiring a pro, who has experience with your chosen wall type? Will you need to rent or buy specialized equipment (concrete mixer, hoist, etc.) to assemble the wall structure or install insulation? If you or your builder are not familiar with a particular building technology, plan on a longer construction schedule.
Materials: Are the wall system’s components made with renewable, recycled, or nonrenewable materials? Are the materials inert once installed or will they off-gas, potentially compromising indoor air quality? What is the embodied energy—the energy required to fabricate and transport—of each of the materials?
Think beyond R-values: Although the thermal performance of a wall is certainly important and higher R-values usually mean less energy consumption, don’t forget about air sealing, a crucial element not only for energy efficiency but also for the durability of the building. Houses should be tested with a blower door during construction so air leaks can be corrected.
Durability: Are the materials you chose insect- and pest-resistant? Will the insulation degrade over time, losing some of its value?
Resistance to thermal bridging & air infiltration: Does the complete wall system limit thermal bridging and air infiltration?
Quality of construction: Even the best materials won’t make up for sloppy building practices. It takes time, care, and expertise to detail buildings so they’re comfortable, durable, and energy efficient. If you don’t know what you’re doing, hire someone who does.