Measuring airflows at registers is a central issue in all HVAC (Heating Ventilation and Air Conditioning) studies. It is a basic measurement that is required in many Cooling/Heating systems tests and in air conditioner performance diagnostics. These measurements can, for instance, be used to determine if individual rooms receive adequate airflow in terms of comfort, to estimate total air handler flow and supply/return imbalances, and to assess duct air leakage. First, I calibrated the Minneapolis Duct Blasters, useful in the most accurate flow hood we have, then I worked on an existing project: measuring airflows with laundry baskets. Finally, I developed a new flow hood with a goal of being inexpensive while remaining sufficiently accurate (around 10%). This hood can be used by anyone independently, and at home. This work is knows as the garbage bag project.