Useful tools for retrofit assessments:

The Energy Conservatory (TEC)-
Code applies to all TEC products!

 Code: mean2023

High resolution manometer (DG8)

DG8 with airflow measuring kit (truflow grid)

TruTechTools- 
Code applies to most products!

Code: MeanHVAC

Laser measurement

Thermal measuerment

Thermal imaging

Amazon

(No Code)

Alternate laser measure

Crochet hook