1. Quality Install Testing
Procedures for Forced Air
Systems

2. Quality Installation: Outcomes
• Installation practices have links to
• Comfort
• Humidity Levels (dehumidification)
• Reduced Utility Consumption
• Indoor Air Quality

3. Why Test?
• SEER reduced when airflow not correct
• High Static = more power draw on ECMs
• ECMs start to draw more power at .8” wc
• Must know system performance to
consider ECM upgrade

4. Why Test?
• Coils, filters, ductwork (flexible lines
worst), registers all add to Total External
Static Pressure (TESP)
• High static pressure makes more noise
• Flow directly effects comfort
• No test is just a guess

5. Two Main Tests
• Total External Static Pressure
• Air Flow CFM

6. What is Rated TESP?

7. What is TESP?
All components add
resistance. Too much
restricts flow.

8. Testing TESP
Static Pressure Tube and Manometer

9. Testing TESP
Pitot Tube and Manometer

10. Testing TESP (Heat Only)
• TESP = top of heat
exchanger to bottom of
blower (after filter)
• Pressure Drop =
change over a distance
(AC coil, filter, etc.
• Check rating (includes
coil? Filter?)

11. Testing TESP Rooftop units
• TESP = Supply and
return
• Pressure Drop =
change over a distance
(AC coil, filter, etc.
• Rated TESP, coil
included in package
units.

12. Testing TESP
• TESP = Add two
numbers together
• Pressure Drop =
subtract numbers
(ignore ± sign)

13. TESP Results
• Think Golf and Blood Pressure
• Lower is better
• High numbers indicate a problem
• And a need for…more practice, exercise
and tweaking the system

14. Example w/no and dirty filter
• 10 After coil • 6 After coil
• 4 Before Filter • 4 Before Filter
• 10 After Filter • 52 After Filter
• 70 Before Coil • 43 Before Coil
• **TESP = 80 • ***TESP total = 95
• **∆P Coil = 62 • ∆P Coil = 38
• ∆P Filter = 2 • **∆P Filter = 48

15. Testing Air Flow (CFM)
• Static Pressure affects air flow
• Air flow determines efficiency
• Need air flow to set refrigerant
• Need 400~ cfm per ton of cooling
• Need to know # of tons

16. Testing Air Flow
True Flow Meter®

17. True Flow Meter®
• Energy Conservatory, MN Manufacturer
• Advantages: very accurate, fairly easy to
set up
• Disadvantages: Equipment can be
expensive, needs filter slot that fits plates,
can be effected by poor duct design

18. True Flow Meter®
• Install in filter slot
• Meter automatically averages flow rates
• Needs manometer (pressure gauge)

19. Testing Air Flow
Hot Wire or Mini-Vane Anenometer

20. Hot Wire or Mini Vane
• Advantages: Fast and east to use,
accurate (when compared to True Flow
meter)
• Disadvantages: Cost, need linear section
of duct

21. Hot Wire or Mini Vane
• Drill holes in duct
• Take readings
• Meter automatically calculates flow rates

22. Testing Air Flow
Hotwire or Mini-Vane Anenometer

23. TESP
• Advantages: Low cost, Quick and easy (if
table available), good for troubleshooting
• Disadvantages: Fan tables sometimes not
available (can use generic), duct
configurations may cause turbulence

24. TESP
• Take readings
• Know fan speed setting, rated TESP
• Match readings off fan table to find CFM

25. Fan Table

26. Potential Problems Found
Restrictive filter (up to 50% drop in flow) Restrictive designer registers

27. Potential Problems Found
Dirty AC Coils Owner did not know it existed

28. Potential Problems Found
Dirty Fan Blades
Leaky Ductwork

29. Possible Solutions
• Less restrictive filters
• Regular filter changes, maintenance
• Curved ductwork, turning vanes
• Registers with free air
• Smooth ductwork, not flex duct
• Proper sizing of ductwork
• Sealing ductwork

30. Challenges
• Additional testing often means more cost
• Additions to ductwork can add cost to
proposal
• “Low Bid” vs. most responsible bid
• Customer education
• Contractor education

31. Benefits
• Energy Savings (that is expected and
predicted)
• Increased Comfort
• Better customer service

32. Thank You
Bruce Stahlberg, CEM
Affordable Energy Solutions, Inc.
Minneapolis, MN