Understanding and Taking Static Pressure Readings Can Help Transform Your Business
Airflow in residential HVAC systems is o5en overlooked and rarely measured, yet it is the
lifeblood of every system. The easiest way to determine airflow in an HVAC system is through
static pressure measurement, which can be completed in just a few minutes.
Static pressure (or total static) in residential HVAC systems should be 0.5 or 1/2 in/wc (inches of
water column). When static pressure is too high, airflow decreases. When it’s too low, this can
indicate several problems, such as leaking or open ductwork. Both high and low readings can
signal serious issues.A helpful analogy to remember is that static pressure is similar to blood pressure – too high or
too low could spell trouble. Just as a blood pressure reading of 120/80 is ideal for humans, a
static pressure reading of 0.5 in/wc indicates a healthy residential HVAC system. This
comparison is particularly useful when explaining static pressure problems to customers and
discussing necessary corrective actions.Surprisingly, as an engineer who has visited hundreds of problem projects, I’ve seen various
HVAC companies’ contact information stickers on furnaces, but I’ve rarely encountered properly
drilled holes for taking static pressure readings. This oversight is puzzling given the importance
of these measurements.Taking static pressure readings at the furnace is a straightforward process. We recommend
investing in a good digital manometer, which is relatively inexpensive, or using a magnehelic
gauge. As shown in the diagram, taking several static pressure readings – creating what’s known
as a static pressure map – will reveal any existing problems and their locations. It’s worth noting
that most residential HVAC systems operate under high static pressure, primarily due to
restricted supply or return ductwork, or dirty/thick pleated filters.The diagram demonstrates how static pressure readings can identify various issues, including
excessive pressure drops across filters, clogged or dirty evaporator coils, and restricted or open
supply or return ductwork. Remember that residential HVAC systems, regardless of
manufacturer, are designed for specific airflow and static pressure parameters. A5er taking
static pressure readings, it’s essential to compare them to a standard airflow chart.For those interested in learning more about implementing static pressure readings during
service calls, we recommend watching “Static Pressure Testing and Mapping Demonstration:
Home HVAC Duct Performance” on YouTube.Stay tuned for our upcoming free online static pressure webinar, open to all interested parties.
Watch for the EP Homiek technical webinar invitation in your inbox.
