1. Quality Passion Knowledge
Design Strategies for
Comfort
Building Technology IV
University of Texas, San Antonio

2. IBS Advisors
Consulting Education MediaProvider

3. Brett Dillon
• Managing Director, IBS
Advisors, LLC
• Member, RESNET Board of
Directors
• Chair, RESNET Technical
Committee
• Member, RESNET Training &
Education Committee
• USGBC LEED for Homes
Green Rater Faculty™
• RESNET-accredited Trainer
• RESNET-accredited Quality
Assurance Designee
• 4th Generation Builder
• Author of books on:
• HVAC
• Weatherization
• Advanced building
techniques
• HERS Ratings

4. 5 Comfort
Factors
Structure
Systems
Commissioning

5. Surrounding
Air
Temperature
68º F, heating
78º F, cooling

6. Moisture
Levels in Air
30%-50% RH
< 80º F Dewpoint

7. Velocity of
Airflow
> 25 fpm
< 50 fpm

8. Evaporative
Rate
Related to Moisture
Related to Air Velocity

9. Clothing
Levels
Related to Culture & Lifestyle

10. Temperature
Control
Shelter from sun
Maintain warmth Garage Living
Space
Living
Space
Living
Space

11. Temperature
Controls
Shade

12. Temperature Controls
Solar
Radiation
Absorptance
Transmittance
Albedo

13. Temperature Controls
Uave = (U1 x A1) + (U2 x A2) / Atot
Q = U x A x ΔT

14. Temperature Controls

18. Siding,
1.5
WRB, 58
OSB,
Insulation,
varies
Primed & Painted
Drywall,
2
Building Material ~ Perm Rating
Fiber cement siding 1.5
OSB 0.75
Primed & Painted Gypsum Board 2
Tyvek® Housewrap 58
Cellulose 75
Fiberglass 120
Open cell spray foam 10
Closed cell spray foam 0.86

19. Airflow
Velocity
Hole
Pressure Difference

22. Stack Effect

23. Mechanical Systems
• Kitchen Range Hood
• Bath Exhaust
• Clothes Dryer
• Ducted HVAC

24. Evaporative Rate

25. Clothing Levels

26. Systems
System Concept
Load Calculation
Equipment Selection
Air Distribution
Duct Size Calculation
Adjust,Test & Balance
Manual RS
Manual J
Manual T
Manual S
Manual D

27. Heating Cooling
T-stat setpoint 70°F 75°F
RH 25% 40%
Temp @ T-stat 68°F - 72°F 72°F - 78°F
Room-Room or Level-
Level ∆ T
+ 4°F + 6°F
Temp in any room + 2°F of set point + 3°F of set point
Floor temp over slab or
unconditioned space
> 65°F, 4” above floor
Filtration > MERV 8 > MERV 8
Ventilation
7.5 cfm/person + 1 cfm/
100 ft2
7.5 cfm/person + 1
cfm/100 ft2
Duct Leakage < 6% < 6%

29. Spread
Manual T

30. Sensible
Heat Ratio
Supply
Air
Room Air
Temperature
Difference
< 80% 54 75 21
80% to 85% 56 75 19
> 85% 58 75 17
Manual S

32. Manual D
• Required under IRC M1601.1
• Implies room-by-room load calculation must be
performed
• CFM
• SHR
• ΔT supply-return
• Sensible load
• Friction rate
• Pressure drop x 100 / total effective length

33. Supply Duct Sizing
• What temperature does the air need to
be to meet the load?
• How many CFM of air must be
delivered to meet the load?
• Sensible Load / (1.1 x ΔT)

34. Duct Layout
Trunk and Branch SpiderRadial

35. Courtesy of Building America Industrialized
Housing Partnership, FSEC & Dennis Stroer

46. Commissioning

48. AAAS.org