Building Assessment and Data Collection
Core concepts
Assessment begins with a scope and objective - what question are you answering? Then select measurement tools matched to the hypothesis: blower door for envelope tightness, duct blaster for duct leakage, infrared camera for thermal anomalies, moisture meters for material wetness. Understand sampling and representativeness: a single spot reading may not represent a whole assembly. Know baseline conditions (weather, occupancy, HVAC state) and record them. Distinguish screening (fast, broad, indicative) from diagnostic (precise, targeted) methods. Understand calibration and measurement uncertainty so data are defensible.
Traps
Questions often test which tool answers which question. A moisture meter reads surface or pin-resistance, not absolute water content of every material - species and temperature corrections matter. Infrared cameras require temperature difference across the assembly; a neutral day shows nothing. Blower door results depend on pressure reference (inside vs. outside) and weather. Another trap: treating a screening reading as a definitive diagnosis. Also watch confirmation bias - collecting only data that supports a pet theory.
Worked example / rule of thumb
Blower door at 50 Pa gives CFM50; divide by conditioned volume for ACH50, or by envelope area for CFM50 per ft². Rule of thumb: state the reference every time you report a number. If a reading seems anomalous, re-measure and note conditions rather than discarding it.
Study approach
For each tool, know: what it measures, its units, its limits, and its confounders. Build a mental matrix of tool-to-question mapping.