Quiz: How Well Do You Know Insulation?

1) BuildingGreen doesn’t recommend radiant barrier products. Why not?

(a) they are not a substitute for conventional insulation
(b) there are minimal differences between products
(c) it is common for radiant barrier manufacturers to mislead consumers on best practices
(d) they have limited practical application, mainly for reducing cooling loads in very specific applications
(e) they are “tested by NASA,” which operates spaceships in outer space—a very different thermal environment than we have here on Earth
(f) all of the above

2) When designing exterior wall and roof assemblies (including taking into account your insulation choice and its vapor permeability), which vehicle for water movement is the highest priority to consider?

(a) bulk water
(b) capillary water
(c) air-transported moisture
(d) vapor diffusion

3) To avoid moisture-related risks, the best place to put insulation is:

(a) to the exterior of the wall cavity
(b) inside the wall cavity
(c) to the interior of the wall cavity
(d) it depends on the climate

4) In order for a radiant barrier to be effective, it must:

(a) face inward
(b) face outward
(c) face an open space
(d) have continuous contact with the surface of an insulation material such as rigid foam

5) Air Krete, the foamed inorganic cement insulation, offers which of the following advantages over conventional insulation?

(a) high R-value
(b) insect and moisture resistance
(c) it acts as an air barrier
(d) all of the above

6) Concerns about toxic chemical ingredients have been raised about which of the following insulation types?

(a) cellulose
(b) expanded polystyrene (EPS)
(c) rigid fiberglass board
(d) mineral wool
(e) all of the above

7) True or false? The best way to negate the embodied energy of insulation (the energy used to manufacture the product) is to use a lot of it so that you save operating energy over the 60-plus-year lifespan of the product.

True
False

8) When measuring the R-value of insulation concrete forms or rammed earth walls that incorporate insulation, the most recommended measure of R-value is:

(a) mass-enhanced R-value
(b) effective R-value
(c) steady-state R-value
(d) mean radiant temperature

9) BuildingGreen recommends specifying what kinds of rigid boardstock insulation?

(a) Mineral wool with third-party verification of low formaldehyde emissions
(b) Insulation made to highly expand with blowing agents, such as extruded polystyrene (XPS)
(c) Expanded cork or wood-based boards
(d) Fire-safe insulation containing halogenated flame retardants
(e) a and c
(f) b and d

10) BuildingGreen recommends the following spray-foam insulation products for below-grade applications:

(a) spray polyurethane foam (SPF) with blowing agents made with low-GWP hydrofluoroolefins (HFOs)
(b) open-cell, low-density SPF foamed with water
(c) closed-cell SPF using HFC-245fa blowing agent
(d) polyurethane-free materials such as damp-spray cellulose

Answer key

1) (f) All of the above. See Radiant Barriers and Reflective Insulation, and our guide to choosing radiant barriers.

2) (a) Bulk water. Insulation restricts the flow of heat, which in turn reduces the ability of wet building assemblies to dry out. If we use a lot of insulation, we must manage the movement of moisture with equal intensity. Bulk water is the biggest source of moisture (probably) and once a wall assembly gets wet from bulk water, it needs to be able to dry out. See How Water Moves Through Buildings.

3) (a) To the exterior of the wall cavity. See The Hidden Science of High-Performance Building Assemblies.

4) (c) Face an open space: an air space is required on at least one side of a radiant barrier in order for it to function as designed. See our product guide to Radiant Barriers.

5) (b) Insect and moisture resistance. See “What About Air Krete?” A Deeper Look at the Insulation Alternative.

6) (e) All of the above. See Can We Replace Foam Insulation? and Toxicological Riddles: The Case of Boric Acid.

7) False—in our opinion. Using enough insulation to keep heating and cooling loads low, and to pay back your investment within a few years definitely makes sense. But if you’re using so much insulation that your payback is stretching out over decades, you should consider Building Materials and the Time Value of Carbon.

8) (c) Steady-state R-value. See our guide to Insulating Concrete Forms, and SIREWALL: The Next Generation of Earthen Walls.

9 (e) a and c. See The Great Eight: High-Impact Material Choices for Green Building.

10) (a) Spray polyurethane foam (SPF) with blowing agents made with low-GWP hydrofluoroolefins (HFOs). See our guide to Spray-Foam Insulation.

What do you think? What answers surprised you? Are there any you think are debatable, and why? Comment below.