When Buildings Overheat, and Ducts Get Complicated: Why Fancy Systems Aren't the Solution
When Smart Systems Fail to Deliver
Imagine completing a project where everything looks impressive on paper. The windows are triple-pane and filled with argon. The walls are constructed with materials that store carbon. The mechanical setup includes a whole-house ventilation system connected to an app, a radiant cooling layout, and smart thermostats that clients appreciate but don't fully understand.
Everyone leaves the final walkthrough feeling confident about the building's performance. Then, the first heatwave hits, and the complaints start. The house feels warm in unexpected areas, cooling loads exceed expectations, and the ductwork twists awkwardly around beams and joists. Additional fan coil units are installed under windows to make certain rooms usable.
In these situations, it's easy to blame the equipment, controls, or installer. However, the more honest answer is that a fundamental design flaw was overlooked. The design didn't set the building up for success.
This is the reminder that mechanical engineer Mark Rosenbaum shared during a recent BS and Beer Show conversation. With over forty years of experience, he emphasizes that technology amplifies the underlying design. If the design is flawed, technology will only magnify the issues.
Two Homes, One Lesson
To illustrate this point, Mark shared the stories of two homes. Both were created by teams focused on energy efficiency and comfort, with clients who wanted functional buildings rather than showpieces. However, their approaches were vastly different.
The first home was a compact two-family building in an urban neighborhood. Its simple, compact shape, restrained window sizing, and thoughtful placement respected the sun's path. It wasn't experimental but fit together logically.
The second home, a custom project on a rural site, boasted thick insulation, triple-pane windows with low emissivity coatings, and environmentally conscious cladding. On paper, it appeared to be a high-performance marvel.
Surprisingly, over ten years, the smaller, simpler house used less energy and had a lower carbon impact. The custom home consumed more energy than expected, despite its advanced materials. The reasons were clear: its extensive exterior surface area and high glass-to-size ratio created paths for heat loss and gain. The geometry demanded more from the mechanical system than a compact form would have.
The modest duplex outperformed the high-end home by adhering to basic principles. Good design quietly outperformed expensive products.
Why Design Thinking Outshines Bigger Equipment
Mark expanded the discussion to larger projects on college campuses, demonstrating that simple, thoughtful design can scale effectively.
A classroom building at Dartmouth exemplified this. It maintained comfort without heating equipment along every exterior wall, thanks to a tight envelope, triple-glazed windows, and strategic glass placement. Fresh air was introduced through a system that allowed occupants to control ventilation. The building worked harmoniously with its mechanical system.
At the Sloan School at MIT, integrating structural and mechanical systems reduced the need for extensive insulation and sealing. Water-based heating and cooling systems moved energy efficiently, reducing equipment requirements.
These buildings didn't rely on miracle equipment. They succeeded because their design minimized loads. Mark noted that some projects achieved about one thousand square feet per ton of cooling capacity, while others required twice the equipment. The difference lay in geometry and layout, not gadgets.
Quiet Metrics That Matter More Than Buzzwords
In high-performance discussions, it's easy to get lost in acronyms and product names. Mark refocused on simple metrics that consistently influence building behavior:
Modest window area relative to floor area simplifies temperature management while providing ample daylight.
Low exterior surface area relative to interior space reduces heat loss or gain, easing insulation and air sealing.
South-facing glass in cold climates allows the low winter sun to warm the building.
Compact building forms reduce construction costs and energy use.
He humorously noted that when ductwork requires cutting into structural members, the problem began long before the mechanical contractor arrived. If the design is awkward, no equipment can make it graceful.
When Ratings and Rebates Distract from the Real Goal
Mark highlighted a common issue: projects designed to pass tests rather than serve occupants. Expensive energy recovery ventilators and heat pump layouts often prioritize certification checklists over practical needs.
While certifications and incentives can drive industry improvement, they become problematic when they overshadow fundamentals. Chasing points and payouts can lead to unnecessarily complex systems that are difficult to live with.
Buildings respond to physics and occupant behavior. If fundamentals are lacking, no certification will ensure comfort year-round.
Final Pour: Simplicity and Thoughtfulness Over Complexity
The conversation concluded with a clear theme: successful projects are rarely the loudest or most complex. They excel because they handle basics so well that the building feels effortless.
These buildings share common traits: intentional sun path use, calm and compact shapes, strategic glass placement, and early planning for ducts and pipes. They reduce heating and cooling loads, allowing for smaller, simpler mechanical systems.
High-performance materials and smart controls enhance good design but should follow fundamentals, not replace them.
Ultimately, the smartest buildings don't need to show off. They work seamlessly, day after day, thanks to thoughtful decisions made long before equipment is ordered.