DRAFT GreenPoint Rated Existing Home Rating Manual version 6.0 | Page 80

H

Heating, Ventilation, and Air Conditioning

H12.

HUMIDITY CONTROL SYSTEMS

CRITERIA FOR QUALIFICATION Note: This measure applies only to single family homes. This measure applies only in California Climate Zones 1, 3, 5, 6, and 7. One point of credit is available for the following: ? ? Conduct a detailed analysis of moisture loads to determine if there is a need for a central dehumidification control system (i.e., a separate dehumidification system or a humidistat controlled variable speed air conditioning unit). Where needed, install a humidity control system to maintain humidity ratios below 0.012 (lb. water vapor/lb. dry air), per Section 52.2 of ASHRAE Standard 55-2004.

Humidity control equipment should be selected to maintain maximum humidity levels based on the summer design indoor air temperature, as shown in the following table: Thermal Environment Conditions for Required Humidity Comfort Control Summer Indoor Design Temperature (°F) 70° F 74° F 78° F 82° F VERIFICATION Field Verification: The Rater will conduct field compliance verification. Documentation: The Rater must collect the following: ? ? An Accountability Form signed by the mechanical engineer or other responsible professional A report of analysis of moisture load and calculations for dehumidification strategy Relative Humidity (%) 76% 66% 58% 50% Humidity Ratio (lb. water vapor/lb. dry air) 0.012 0.012 0.012 0.012

INTENT To improve indoor air quality in high humidity climates.

H13.

REGISTER DESIGN MEETS ACCA MANUAL T

CRITERIA FOR QUALIFICATION Note: This measure applies only to single family homes. One point of credit is available for installing supply and return registers and grilles according to ACCA Manual T.

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GreenPoint Rated Existing Home Rating Manual Version 6.0, September 2013 © Build It Green