Technician’s Guide and Workbook for Zoning Section 2: Zoning Types and Design Decisions

Zoning Methods There are an unlimited number of ways to zone a home! Popular ways include: More than one single zone HVAC system. Zone damper systems. Combinations of different types of HVAC equipment. Heat transfer based on hydronic, air, or refrigerant based heat exchangers. Mini-split systems and individual room units. Cooling or heating only zones.

More Than one Single Zone System Zone 1 2nd Floor Zone 2 1st Floor Zone 3 Basement

Different Equipment Types Boiler Mini-Split Electric Strip PTAC PTAC = Packaged Terminal Air Conditioner

Zone Serves More Than One Area Zone 1 2nd Floor Zone 2 1st Floor Zone 2 Basement

Zone For Each Floor Level Zone 1 1st Floor Zone 2 Basement

Heat Transfer: Air, Water, or Refrigerant

Zoning Decisions Zoning decisions are based on many factors. Some are listed below: Owner Input Remote Rooms (location) Life-Style Spaces Zone by Level Zone by Exposure Zone by Construction type

Owner Input Master Bedroom In-law Suite Baby’s Room Game Room and Bar Over Garage Wine Storage Room

Remote Room Locations Kitchen Great Room ½ Bath Laundry Dining Garage

Life-Style Rooms Master Bedroom Bed 2 Card Room & Bed 3 Bar Bath Closet Card Room & Bar Bath Bed 3

Zone For Each Floor Level Zone 1 2nd Floor Zone 2 First Floor

Zone By Exposure Zone 2 East Side Zone 1 West Side

Peak Fenestration Loads Exposure Month Hour Comment North Mid-Summer Relatively Constant Diffuser radiation gain, conduction peaks in late afternoon. East 9-11 AM Low sun angle, 1ft overhang not effective. South Fall 1-3 PM High sun angle, 1ft overhang is effective. West 5-7 PM Horizontal Mid-Day Use exposure direction for tilted skylights. Block Load Normal amount of southern-facing glass. Large amount of southern-facing glass Incomplete spaces are easily identified when hourly fenestration loads are graphed for time-of-day.

Exposure Load Chart 4-5 PM 4,500 4,000 3,500 3,000 2,500 2,000 1,500 1,000 500 BTUH 9 10 11 12 13 14 15 16 17 18 19 Hour of the Day 4-5 PM

Zone By Construction Type Additions or rooms with different types of windows and insulation treated different.

Zone For Cooling/Heating Loads Manual J cooling load is not equal to the Manual J heating load very often. Manual D duct design is based on the Larger of the two. Final airflow provided to the space is often a compromise between cooling and heating requirements.

Cooling/Heating (C/H) If Heating CFM = Cooling CFM : C/H = 1 What is the ratio if the cooling CFM is 120 and the heating CFM is 60? 120 ÷ 60 = 2 What is the ratio if the cooling CFM is 60 and the heating CFM is 120? 60 ÷ 120 = 0.5

Cooling/Heating (C/H) If Heating CFM = Cooling CFM : C/H = 1 What is the ratio if the cooling CFM is 88 and the heating CFM is 76? 88 ÷ 76 = 1.158 What is the ratio if the cooling CFM is 76 and the heating CFM is 88? 76 ÷ 88 = 0.864

Final Air Balance Affects Temperature Air Balancing Method Affects Temperature Swing Room 1 2 3 4 5 6 7 8 Cooling CFM 116 138 119 130 113 151 162 63 Heating CFM 87 111 109 108 126 128 136 75 Average CFM 101.5 124.5 114 119.5 139.5 149 69 XS H-CFM BC 33.3% 24.3% 9.2% 20.4% -10.3% 18% 19.1% - 16% XS C-CFM BH -25% -19.6% -8.4% -16.9% 11.5% -15.2% -16% 19% XS H-CFM BA 16.7% 12.2% 4.6% 10.2% -5.2% 9% 9.6% -8% XS C-CFM BA -12.5% -9.8% -4.2% -8.5% 5.8% -7.6% 9.5% XS H-CFM BC: Excess heating CFM when the system is balanced for cooling. XS C-CFM BH: Excess cooling CFM when the system is balanced for heating. XS H-CFM BA: Excess heating CFM when the system is balanced for average CFM. XS C-CFM BA: Excess cooling CFM when the system is balanced for average CFM.

Air Balance Design Percentages Air Balancing Method Affects Temperature Swing Room 1 2 3 4 5 6 7 8 Cooling CFM 116 138 119 130 113 151 162 63 Heating CFM 87 111 109 108 126 128 136 75 Average CFM 101.5 124.5 114 119.5 139.5 149 69 XS H-CFM BC 33.3% 24.3% 9.2% 20.4% -10.3% 18% 19.1% - 16% XS C-CFM BH -25% -19.6% -8.4% -16.9% 11.5% -15.2% -16% 19% XS H-CFM BA 16.7% 12.2% 4.6% 10.2% -5.2% 9% 9.6% -8% XS C-CFM BA -12.5% -9.8% -4.2% -8.5% 5.8% -7.6% 9.5% XS H-CFM BC: Excess heating CFM when the system is balanced for cooling. XS C-CFM BH: Excess cooling CFM when the system is balanced for heating. XS H-CFM BA: Excess heating CFM when the system is balanced for average CFM. XS C-CFM BA: Excess cooling CFM when the system is balanced for average CFM.

Air Balance Design Percentages Air Balancing Method Affects Temperature Swing Room 1 2 3 4 5 6 7 8 Cooling CFM 116 138 119 130 113 151 162 63 Heating CFM 87 111 109 108 126 128 136 75 Average CFM 101.5 124.5 114 119.5 139.5 149 69 XS H-CFM BC 33.3% 24.3% 9.2% 20.4% -10.3% 18% 19.1% - 16% XS C-CFM BH -25% -19.6% -8.4% -16.9% 11.5% -15.2% -16% 19% XS H-CFM BA 16.7% 12.2% 4.6% 10.2% -5.2% 9% 9.6% -8% XS C-CFM BA -12.5% -9.8% -4.2% -8.5% 5.8% -7.6% 9.5% XS H-CFM BC: Excess heating CFM when the system is balanced for cooling. XS C-CFM BH: Excess cooling CFM when the system is balanced for heating. XS H-CFM BA: Excess heating CFM when the system is balanced for average CFM. XS C-CFM BA: Excess cooling CFM when the system is balanced for average CFM.

Calculating Percentages What is 25 percent of 100? (25 ÷ 100) × 100 = 25 (or 0.25 × 100) What is 23 percent of 73? (23 ÷ 100) × 73 = 16.79 (or 0.23 × 73) What is 123 percent of 75? (123 ÷ 100) × 75 = 92.25 (or 1.23 × 75) What is 14.2 percent of 376? (14.2 ÷ 100) × 376 = 53.392 (or 0.142 × 376)

Calculating XSHcfmBC Percentages Air Balancing Method Affects Temperature Swing Room 1 2 3 4 5 6 7 8 Cooling CFM 116 138 119 130 113 151 162 63 Heating CFM 87 111 109 108 126 128 136 75 Average CFM 101.5 124.5 114 119.5 139.5 149 69 XS H-CFM BC 33.3% 24.3% 9.2% 20.4% -10.3% 18% 19.1% - 16% XS C-CFM BH -25% -19.6% -8.4% -16.9% 11.5% -15.2% -16% 19% XS H-CFM BA 16.7% 12.2% 4.6% 10.2% -5.2% 9% 9.6% -8% XS C-CFM BA -12.5% -9.8% -4.2% -8.5% 5.8% -7.6% 9.5% XS H-CFM BC: Excess heating CFM when the system is balanced for cooling. XS C-CFM BH: Excess cooling CFM when the system is balanced for heating. XS H-CFM BA: Excess heating CFM when the system is balanced for average CFM. XS C-CFM BA: Excess cooling CFM when the system is balanced for average CFM. [(116 ÷ 87) – 1] × 100 = 33.333%

Calculating XS CcfmBH Percentages Air Balancing Method Affects Temperature Swing Room 1 2 3 4 5 6 7 8 Cooling CFM 116 138 119 130 113 151 162 63 Heating CFM 87 111 109 108 126 128 136 75 Average CFM 101.5 124.5 114 119.5 139.5 149 69 XS H-CFM BC 33.3% 24.3% 9.2% 20.4% -10.3% 18% 19.1% - 16% XS C-CFM BH -25% -19.6% -8.4% -16.9% 11.5% -15.2% -16% 19% XS H-CFM BA 16.7% 12.2% 4.6% 10.2% -5.2% 9% 9.6% -8% XS C-CFM BA -12.5% -9.8% -4.2% -8.5% 5.8% -7.6% 9.5% XS H-CFM BC: Excess heating CFM when the system is balanced for cooling. XS C-CFM BH: Excess cooling CFM when the system is balanced for heating. XS H-CFM BA: Excess heating CFM when the system is balanced for average CFM. XS C-CFM BA: Excess cooling CFM when the system is balanced for average CFM. [ (87 ÷ 116) -1] × 100 = -25%

Design CFM For Balancing The actual airflow to be sent to each area/room when the system is balanced is calculated using percentages. That final calculation must be done in the field after the total CFM airflow is established, and the airflow across the heat exchanger is within 10% of the Manual S equipment airflow value.

Field Notes The complaint is simple, and if you start doing airflow balancing in homes that were never balanced, you will hear it often: This room is always too cold in the summer, and then the funniest thing happens, in the winter it is just the opposite, and it is always too hot. The room obviously was not balanced correctly and it is always getting too much airflow.