flexiblefullpage -
Currently Reading

A Case for Compact Duct Layouts

Advertisement
billboard -
Construction

A Case for Compact Duct Layouts

Energy and building codes now require a high level of insulation, high-performance glazing, and better air sealing—compact duct layouts may help


By Tim Kampert May 9, 2022
compact duct layouts can work if you do them right

Conventional duct layouts place HVAC supply registers near exterior walls because those locations used to make sense: Homes of the past were poorly insulated and drafty, causing interior surfaces of perimeter walls to get cold in winter and hot in summer; blowing conditioned air across them evened out room temperatures and diluted those drafts. 

With that, most conventional forced-air systems place the air handler in the attic— a location that requires long duct runs to reach the room registers at the edges of the floor plan. The result: lots of exposed ductwork in unconditioned attics, which increases thermal loss through pressure differences and duct leaks and forces the system to work harder to maintain setpoint temperatures. 

But building is different today. Energy and building codes now require a high level of insulation, high-performance glazing, and better air sealing, so the temperature of perimeter walls doesn’t fluctuate nearly as much as it used to. 


compact duct layouts


The Case for Compact Layouts

That’s why some builders have switched to compact duct layouts. To deliver supply air more efficiently, such designs place the air handling unit (AHU) in conditioned space near the center of the home. Multiple plenums placed throughout the floor plan enable fewer, and shorter, duct runs from the AHU to diffusers in the ceiling or high on the wall of each room or area (see diagrams, opposite page).

Reducing duct material and installation labor by not running ducts to the exterior walls means compact layouts save builders money on every house.

Some builders still worry that they must wash exterior walls with conditioned air, but today’s windows and code-mandated envelope details really do eliminate that need. In fact, the production builders we have helped to implement this approach report fewer indoor comfort complaints from homeowners.


tips on compact duct layout


Attention to Detail

There are two caveats when it comes to compact duct layouts, but they’re neither complicated nor difficult.

The first is that installers must be careful not to kink ducts during installation (which they shouldn’t do, regardless). Kinking is less of a concern with long, conventional runs that can be gently arched, but shorter runs tend to create tighter turns that may make them more likely to get pinched around framing members or when entering a boot connection.

The second is that, unlike conventional stamped registers in the ceiling or floor, you need to use ceiling- or wall-mounted diffusers, which have directional fins designed to serve larger areas. We recommend diffusers with curved blades, so that air is evenly spread across the ceiling and then gradually falls into the room. Once the system is on, the installer can adjust the diffusers for optimal comfort.

Note that diffusers cannot be placed on the floor. That’s not an issue with slabon-grade homes, but if the plenum runs through a basement or crawlspace, then diffusers must be located high on interior walls.

Diffusing Resistance

As for implementation, we find it takes the typical production builder about a year to redesign the ductwork in all of its floor plans and to work out any issues associated with installation quality. An alternative is to use compact layouts only on new plans going forward.

Also, while a compact layout takes less time to install, some builders are skeptical about getting HVAC subcontractors to embrace it. The builders we know that have experienced success started with just a few homes, and then, once their trades saw that it made their life easier and reduced callbacks, they readily jumped on board.


Tim Kampert drives quality and performance in home building as a building performance specialist for the PERFORM Builder Solutions team at IBACOS.


This story first ran as part of IBACOS and Pro Builder's joint "Quality Matters" column 

Related Stories

Business

Stretching the Budget to Meet the Massachusetts Stretch Code

We take a look at Massachusetts' Stretch Code and how it's affecting design and construction on The House That Blues Built

Case Studies

The Art of Weaving Custom Homes into the Urban Fabric

These homes demonstrate the challenges and opportunities of custom urban infill

Case Studies

A Pittsburgh Rowhouse With a View

Working mostly within the city limits but in a variety of neighborhoods on different building types, architect Darren Lloyd says every project is instructive for projects that follow, regardless of type.

Case Studies

Cool Desert Design in Tucson

One characteristic common to infill lots is variety. “Infill lots vary depending on what part of the city they’re in,” says architect Luis Ibarra, co…
Leadership

Removing Obstacles

Our approach to land acquisition, analysis, and permitting makes it easier for buyers to gain confidence in a custom home project

Business

Effective Trade Partnerships

Seeing trade partners as equals means showing them respect by valuing their work...

Backstory

From Builder to Influencer

With a social media following surpassing 1 million, builder and influencer Kyle Stumpenhorst is educating a new generation of skilled workers

Construction

2022 Custom Timber Home Building Outlook

A few of top tips from Mid-Atlantic Timberframes for working with timber frame providers, as well as what we’re seeing on the custom timber home building horizon for 2022.

Construction

Net Zero and Beyond

Different roads to energy and resource independence

Construction

Workstation Sink

Ruvati has created a new apron-front version of its dual-tier workstation sink

Advertisement
boombox1 -
Advertisement
boombox2 -
Advertisement
native1 -

More in Category



Case Studies

A Pittsburgh Rowhouse With a View

Working mostly within the city limits but in a variety of neighborhoods on different building types, architect Darren Lloyd says every project is instructive for projects that follow, regardless of type.


Advertisement
native2 -
Advertisement
halfpage1 -