In commercial building design, collaboration is everything—or at least it should be. Yet too often, HVAC system planning enters the conversation after key architectural decisions are already locked in. The result? Costly compromises, awkward retrofits, and systems that work *around* the building instead of *with* it.

From an owner’s perspective, this misalignment affects more than just aesthetics—it impacts energy costs, tenant comfort, and the long-term value of the asset. At the center of the issue is a simple but often-overlooked principle: airflow is architectural. And the sooner engineers say it, the better.

Let’s break down why early airflow planning matters, what goes wrong when it’s ignored, and how solutions like Dedicated Outdoor Air Systems (DOAS) can protect both design integrity and building performance.

 When Buildings Are Beautiful—But Breathe Poorly

Architects invest immense thought into form, light, materiality, and spatial experience. HVAC systems, on the other hand, are about thermal load calculations, duct sizing, and code compliance. These are fundamentally different design languages—and if they’re not translated early in the process, they clash.

We’ve all seen the results:

– Drop ceilings installed to hide oversized ductwork.

– Unsightly soffits interrupting clean interior lines.

– Mechanical rooms shoehorned into valuable leasable space.

– Daylighting strategies undermined by condensation-prone diffusers.

These compromises don’t just affect the architect’s vision—they erode tenant experience and increase lifecycle costs. It’s not that the HVAC system is “wrong,” per se; it’s that it arrived too late to fit seamlessly into the design puzzle.

 The Hidden Cost of Late-Stage Mechanical Design

Late coordination is a common pitfall in the construction process—and HVAC systems often bear the brunt of it.

What starts as a “tight but manageable” design quickly turns into a costly value engineering exercise:

– Duct routes need reworking.

– Equipment must be upsized to handle layout inefficiencies.

– Airflow becomes unbalanced due to layout constraints.

– Architectural elements get sacrificed to hide mechanical infrastructure.

These changes introduce cost overruns, schedule delays, and long-term inefficiencies. And while the building may still function, it often misses the opportunity to be *exceptional*—both in comfort and performance.

 What Architects Actually Want from Mechanical Systems

So what does a good HVAC system look like from an architect’s perspective? It’s not just about heating and cooling—it’s about preserving design intent. Architects are looking for systems that:

– Disappear into the background  

  Minimal visible hardware, low-profile diffusers, and concealed ductwork that doesn’t dominate the space.

– Operate quietly  

  No distracting air noise or equipment hum that undermines the user experience.

– Adapt to different layouts and uses  

  Flexible zoning and scalable components that can handle open offices, private suites, or mixed-use configurations without redesign.

– Respect ceiling heights and finishes  

  Systems that don’t require invasive infrastructure or visual compromises.

Meeting these expectations requires engineers to think spatially, not just mechanically. It also requires solutions that are architecturally friendly by design—which brings us to DOAS.

 DOAS: A Mechanical Solution That Respects the Architecture

Dedicated Outdoor Air Systems (DOAS) are gaining traction because they separate ventilation from temperature control—addressing airflow needs with precision and flexibility. And just as importantly, they allow engineers to deliver performance *without disrupting the architecture*.

Here’s how:

 Smaller, Smarter Infrastructure

Unlike traditional systems that rely on large ductwork to move both ventilation and conditioned air, DOAS delivers only the required outdoor air—and does so with smaller ducts and localized control. This dramatically reduces the ceiling and wall space needed for mechanical distribution.

 Clear Separation of Load Types

DOAS handles latent loads (humidity and ventilation) separately from sensible loads (temperature). That means architects and engineers can zone spaces more creatively—without forcing a compromise between aesthetics and system performance.

It also reduces the size and complexity of the primary HVAC system, enabling sleeker designs like VRF or hydronic fan coils to manage thermal comfort without large equipment footprints.

 Clean Integration with Modern Interiors

Because DOAS systems often utilize decentralized or modular air terminals, they’re easier to integrate invisibly into interior finishes. Low-profile diffusers, linear grilles, or even concealed displacement units all allow for seamless architectural expression.

Case in Point: DOAS in an Architect-Led Mixed-Use Project

Consider a new mixed-use development with retail on the ground floor and boutique offices above. The architect envisioned open ceilings, exposed ductwork, and minimal visual clutter. The engineering team proposed a DOAS paired with a VRF system.

The result?

– Ventilation was handled by a discrete ceiling-mounted DOAS with linear slots hidden in ceiling baffles.

– The primary cooling and heating was delivered via low-profile VRF heads, coordinated with lighting and structure.

– The team avoided unnecessary drop ceilings, maintained the aesthetic vision, and reduced installation costs by nearly 15%.

This project wasn’t just visually clean—it was *mechanically elegant*. And most importantly, it worked as designed, without sacrificing comfort or energy performance.

 How Early Coordination Creates Better HVAC Outcomes

The earlier HVAC design enters the conversation, the better the outcome. That doesn’t mean detailed duct drawings in schematic design—but it *does* mean aligning on core mechanical strategies before floor plans are finalized.

Design Charrettes

Integrated workshops—bringing architects, MEP engineers, and owners together—can establish system constraints, spatial needs, and performance goals early on. These sessions are the birthplace of buildings that function and flow as a single idea.

Building Information Modeling (BIM)

Modern tools like BIM allow teams to test-fit equipment and routes in 3D. Architects can immediately see how systems will impact ceilings, walls, and spaces—and engineers can propose alternatives before problems arise.

Collaborative Planning Saves Rework

When airflow is part of the early design narrative, teams avoid the need for costly re-routing, over-sizing, or change orders. A DOAS strategy, for instance, can be evaluated against space planning and visual design long before construction begins.

 Making the Business Case to the Owner

While architects and engineers are critical to coordination, the ultimate decision-maker is often the owner or developer. And for them, the case for smart airflow design boils down to three things:

 1. Operational Savings

Systems like DOAS, when integrated properly, reduce energy use, extend equipment life, and streamline maintenance. Over the life of the building, these savings are substantial.

 2. Tenant Satisfaction

Better ventilation and thermal control lead to happier occupants—whether it’s employees in a corporate HQ or residents in a luxury apartment. Reduced complaints and improved comfort metrics support tenant retention and property value.

3. Long-Term Flexibility

Buildings evolve. Whether the layout shifts post-occupancy or usage changes in five years, a modular, decoupled HVAC design ensures that your system evolves with it—without gutting the infrastructure.

 Final Word: Design with Air in Mind

In the rush to finish floor plans, lock in finishes, or value-engineer materials, it’s easy to treat HVAC as a utility rather than a design partner. But airflow *is* architectural. When engineers speak up earlier—and when owners push for coordinated planning—systems like DOAS become tools for creativity, not constraints.

By designing for airflow from the start, project teams can create buildings that feel better, cost less to run, and age more gracefully. It’s time engineers were invited to the table sooner—because the best buildings don’t just look great. They breathe well too.