The Green Lab Guide's Superlative Claim
The campus sustainability office issues a 'Green Lab Guide' stating: 'Laboratories consume up to ten times more energy per square foot than office spaces. Therefore, shutting down fume hoods when not in use is the single most effective action a lab can take to reduce its energy footprint.' Later, the guide notes that fume hoods account for about 40% of a laboratory's energy use and that 'many hoods are left open overnight, wasting conditioned air.' A graduate student in chemistry reads the guide and asks whether the recommendation follows from the evidence. She notices that the guide does not compare the savings from hood shutdowns with savings from other possible actions, such as upgrading freezers or adjusting lighting schedules. She also wonders whether the 'ten times' figure applies to her building, which was renovated in 2018 with energy-recovery ventilation. The guide's author is not identified, and no citations are provided.
1. What is the main claim of the guide's argument, and what role does the 40% statistic play in that argument?
Read the worked answer
The main claim is that shutting down fume hoods when not in use is 'the single most effective action' a lab can take. The 40% statistic functions as evidence that fume hoods are a major energy user, which supports the premise that hoods are worth targeting. But the statistic only establishes magnitude, not comparative rank. To support 'single most effective,' the guide would need evidence that hood shutdown saves more energy than alternatives such as freezer upgrades or lighting changes. The 40% figure is necessary but not sufficient; it cannot by itself justify the superlative. Recognizing this gap is the key comprehension move.
2. Identify an unstated assumption the guide must rely on for its recommendation to be valid.
Read the worked answer
The guide assumes that the 40% share is the largest controllable energy load and that no alternative action could produce equal or greater savings at comparable cost and feasibility. It also assumes that shutting down hoods does not create safety or operational problems, and that the 'ten times' baseline applies to the reader's lab. If the building has energy-recovery ventilation, hoods may be a smaller share, weakening the universal claim. The argument's force depends on these assumptions; without them, the conclusion 'single most effective' is unsupported.
3. How does the detail about the 2018 renovation affect the strength of the guide's recommendation for that building?
Read the worked answer
The renovation detail weakens the recommendation's applicability. The guide's inference relies on a general 'ten times' comparison between labs and offices. If the building has energy-recovery ventilation, its baseline energy profile differs, and hoods may account for less than 40% of consumption. The recommendation might still be good practice, but the superlative claim becomes less justified. A careful reader should treat the guide as a general heuristic, not a proven prescription for every lab. The author's lack of citations further limits confidence. This shows how a specific contextual detail can undercut a universal claim.