An anemometer is a device that measures the speed and direction of the wind. It can be used in HVAC systems to measure the flow of air in the ducts. However, finding an outdoor anemometer that is suitable for use in HVAC systems can be challenging.
One option is to use a homemade pinwheel as a flow meter. While not an ideal anemometer, it can provide a quick and dirty measurement of air flow in HVAC ducts. The pinwheel is custom cut from patterns scaled down from a toy, and a reflective optosensor counts revolutions as the turbine spins in the ducts. With a little calibration, it can produce good results, although there are limitations such as duct turbulence, flimsy construction, and poor bearings.
Another option to consider is a digital anemometer that is specifically designed for use in HVAC systems. These anemometers have robust construction, sturdy bearings, and are calibrated to provide accurate readings in HVAC ducts. They can also measure temperature and humidity levels, making them an all-in-one solution for HVAC flow measurement.
Overall, finding the right anemometer for your HVAC system depends on your specific needs and budget. While a homemade pinwheel may be a suitable option for a quick measurement, a professional-grade digital anemometer may be the better long-term investment. Regardless of which option you choose, ensuring proper air flow in your HVAC ducts is critical for maintaining optimal indoor air quality and energy efficiency.