Residential Attic Ductwork Layout

Typical trunk and branch duct systems.

Residential attic ductwork layout.

From these trunk lines come branch ducts usually round that extend. The residential forced air duct system. Well in the comments dave roberts a senior engineer at the national renewable energy lab nrel wrote about a paper he co authored last year and included a link to it. Often residential ductwork from the original construction was designed inexpensively and without much thought for longevity.

Once all the system variables have been decided your hvac design professional can determine the most efficient ductwork design layout and calculate the correct duct size. Remember that article i wrote about ducts installed against the roof deck and how i said it was probably the absolute worst single location for installing ducts. A duct system located in an attic. I called out the original hvac company and they took a look and said they saw no water.

One of the most important jobs of the designer. Up against the deck may be the worst place in the attic to. This hvac for beginners section begins here with a discussion about forced air duct systems the basics the how and why of duct sizing. Look at the following factors when assessing your aging ductwork design.

Route ducts between joists in a basement if possible or over them if necessary. Avoid any hot elements such as water heaters heater or stove. The most common design trunk line layout is provided in the illustration below. Situate the air handler close to the center of the layout to minimize the length of ductwork spans.

Make the layout as symmetrical as possible with branch ducts spaced evenly along the trunk duct and each branch of similar length. You ve got to know how much heating and cooling you need for each room in btu hr. Duct system design considerations part 1 by roger m hensley cms. There are six basic locations for supply duct systems in residential structures.

This type of system incorporates the use of a trunk line or series of rectangular ducts that act as a main supply channel throughout the house. It was new when the ac was put in 7 years ago. The layout and installation of the duct system will incorporate these basic principles of good ductwork design. Aging ductwork can compromise your system s optimum performance efficiency and air quality.

When were the ducts installed. Designing a duct system is important but there are a few critical steps that come first. Number one is the heating and cooling load calculation using a protocol like acca s manual j or the ashrae handbook of fundamentals. Most residential structures can accommodate one or more of these configura tions.

The attic ductwork is flex duct work. To account for all the necessary factors many professionals use a tool called acca manual d. Choose the right duct size and layout.