We just had A/C and forced air with new duct work installed in an older house. The air flow out of the each duct varies considerably. On duct will not blow off a piece a paper and another feels like a wind tunnel. So my question is there a device to measure the air flow at the registers. What airflow should we be looking for at each register and how much difference between registers is acceptable. All the registers are the same size 3.5" x10"
Thanks for your help.