Documenting HVAC Design Changes

IBACOS has been working with specific Pulte Homes divisions to improve their HVAC designs and how they generate and implement these designs. This is being done through:

• improvements to the designs themselves.
• the application of a systems integration design approach.
• field training and support to ensure proper implementation.

This work involves assessing what's being done well and what could be improved in their current construction practices; creating the most cost-effective design that improves the HVAC system's performance; and applying the new design to all homes in a given division. Throughout, it's important to consider the new design's effect on the home's overall performance (systems integration) and to ensure that the design is implemented effectively in construction.

Step 1: Test the performance of HVAC systems in current homes.

By testing with a blower door, duct blaster and flow hood, IBACOS identifies which aspects of the design work well and which could be improved. It's important to test current performance before starting any new design because parts of the HVAC design or contractor practices always are done well and should be replicated in new designs instead of being altered for no reason.

Step 2: Propose HVAC design changes.

Usually five to seven revised HVAC designs result with varying construction specifications (for example, window type and furnace location) and duct configurations (location, mainly, but also size). Each design needs to balance cost, ease of construction and performance. IBACOS and the Pulte division together review the advantages and drawbacks of each design, and Pulte selects the new design. This design serves as a guideline that IBACOS applies to all types of homes in that Pulte division.

Step 3: Use a systems-integrated approach to determine the relationships be-tween the new design and all other systems in a house.

The final step is another process in and of itself. A systems integration approach recognizes the interactions among the thermal enclosure and the structural, plumbing and HVAC systems, and seeks to coordinate all of them to optimize the home's overall performance and minimize construction costs and field conflicts.

Finally, the design is implemented in production. IBACOS supports the Pulte staff through upfront training, assistance on any modifications deemed necessary as the design is built for the first few times, and performance testing and analysis to ensure that the design performs well.

IBACOS (Integrated Building and Construction Solutions) researches and develops solutions to design, engineering and construction issues, with the goal of helping home builders build quality homes that are consistently designed and built to higher standards of performance and are safe, healthy, durable, comfortable and efficient. More information can be found at www.ibacos.com.