Integrated Design

Integrated Design
The HVAC system must be considered in the early schematic design phase to achieve optimal
performance in an energy efficient house. During the schematic phase, the design team needs to
allocate adequate space for the equipment and ducts while identifying principal potential
conflicts between the building’s structure and the HVAC system. Decisions made during the
early design phase will be critical to the successful performance of the HVAC system.
Locating the HVAC equipment centrally within the house is an early design consideration with
many benefits for the performance of the system and implications for the space planning in the
house. Locating the equipment centrally will allow for shorter duct runs with similar lengths,
which can lead to a better balanced system and improved performance. Centrally located
equipment with shorter duct runs also facilitates running ducts to interior walls with the high
performance strategy of more efficient high sidewall diffusers aimed at the exterior walls.
An energy efficient house utilizes strategies to keep all ductwork inside the thermal boundaries
of the house. Keeping all ductwork inside thermal boundaries will eliminate losses to the outside
of the building enclosure but may require the use of soffits that reduce ceiling heights or chases
that must be designed with the floor plan flow.
A preliminary layout of the duct system can be made on the floor plan, taking into consideration
the performance criteria. By considering a preliminary duct layout, early accommodations can be
made in the framing plan as needed.
Floor systems are a commonly used element to run duct systems within the thermal boundary,
particularly in multistory houses. Creating chases deliberately when designing the floor plan
layout will allow the HVAC system to perform as designed. Considering the location of
horizontal and vertical chases early in the design can decrease the level of complexity in the duct