Arkansas HVACR NewsMagazine November 2019

S tate, National, Chapter News Tech News

construction materials and finishes may be compromised and condensation can occur. It is important to remember the work with airflow takes place in “the occupied zone”. The zone is defined as two feet from interior walls and to six feet above the floor.

Air distributed from a heat pump during heating season is approximately 20 degrees warmer than the air in the room. If the thermostat is set at 70 degrees this means the air distributed is at around 90 degrees. If this air is projected into the occupied space, the 98 degree occupants will feel cool or

drafty air. If distributed properly and airflows are kept below 50 fps the occupants will notice no uncomfortable conditions. Popular styles of grilles today are flat stamped faced or plastic. Neither are efficient at directing air across a room. Generally, these grilles project air down at a 45-degree angle. Engineering firms as far back as 1996 have been

asking contracting community to employ the use of curved blade grilles to properly introduce air into rooms and away from occupied space. Companies that include diagnostics and duct improvements are more profitable and are several terms we need to remember to validate best practices when competing with companies that don’t include duct improvements in their proposals. Your company must be familiar with the terms and the the HVAC

The terminal device or grill must not only distribute the air to the intended target, it must also mix the entrained air. While common thought is only to deliver cool or hot air, there are drawbacks with each option. Generally, what we fix for summer comfort will haunt us in the winter. Likewise if we focus on heat distribution, we may garner complaints in the summer, particularly on multilevel homes. The secret is treating all air distribution systems as you would heat pump air.