Retrofitting HVAC systems should be one of the most straightforward ways to improve building performance. The opportunity is enormous: Millions of existing homes and commercial buildings are operating with aging, inefficient systems that drive up energy costs, reduce comfort and complicate maintenance.

Meanwhile, the problem with HVAC upgrades isn’t about the equipment itself, but barriers, such as intrusive installation requirements, unpredictable project timelines, high upfront costs and tenant disruption, that make upgrades riskier than they should be. The answer is to design HVAC retrofits around these barriers.

The core problem

To a contractor, an HVAC system is never a standalone box. It’s one component inside a larger plan, and how well that system performs depends on how well it integrates with the building it’s going into — the wall assembly, the electrical service, the drainage, the envelope’s ability to stay sealed against weather. Change the system, and you change the demands on all of it.

As a result, a new efficient PTAC under a window, a solution that looks cheap on the spec sheet, can become the most expensive option once the wall, the wiring, the schedule and the lost room nights are added up. The new unit may need a different opening, in a different location, which means cutting the exterior wall. Cutting the wall means first confirming the wall can take the cut, which could mean reframing a header or reinforcing studs. Then the new opening must be finished to keep water out and hold up against wind load, or else, you’ve traded an efficiency upgrade for a moisture problem two years down the road.

None of that shows up in the equipment quote. All of it shows up in the final bill. Then add the electrical panel that wasn’t sized for the new load, the condensate line that has nowhere to drain and the math gets misleading fast.

This is where the industry has historically struggled. Too many retrofit solutions are designed “engineering-first.” In other words, built to meet the design load, rather than meant to be installed economically.

The right question isn’t “What’s the most efficient system?” It’s “What’s the most efficient system we can actually install?” Modularity, high-quality technologies and systems built to respect the buildings they go into are what turn high performance on a spec sheet into high performance in a real building.

Common barriers

Intrusive installation requirements: One of the most persistent challenges in retrofit projects is that construction becomes intrusive. Accommodating a new HVAC system requires new infrastructure. This not only increases labor costs, but also introduces uncertainty, delays and tenant dissatisfaction.

A growing number of solutions are addressing this head-on by minimizing or eliminating the need for structural modifications. Modular HVAC approaches and distributed system designs can often be installed using existing pathways or surface-mounted components. In some cases, refrigerant or hydronic lines can be routed externally or through non-intrusive channels, avoiding the need for demolition altogether.

The key principle is simple: The less you have to disturb the jobsite, the faster and more scalable the retrofit becomes.

In practice, this can mean:

• Leveraging compact, decentralized units instead of large centralized systems

• Using semi-rigid line sets that seal without brazing, allowing faster installation with fewer specialized trades.

• Designing systems that adapt to the building, rather than forcing the building to adapt to the system.

Electrical constraints: Many older buildings aren’t wired for modern HVAC loads, especially for heat pumps, which draw significantly more power than the gas-and-AC systems they’re replacing.

Typical AC paired with a gas furnace runs on a 30-amp breaker and 10-gauge wire — small enough that most electricians stock that gauge by default on their trucks. However, swap that system for a heat pump of equivalent cooling capacity, add the backup electric resistance heat that cold climates require, and total amperage during simultaneous operation can more than double.

In our own analysis of 2-ton units, a gas-furnace system drew about 20 amps where an equivalent heat pump replacement drew 36 to 42 amps. Residential multifamily code caps a single circuit at 60 amps. Once a heat pump plus its electric strip heat crosses that ceiling, the installer isn’t running one circuit. They’re running two. A second circuit means a second breaker, a new wire run and usually pulling the existing wire out of the wall to replace it with a heavier gauge.

On a single unit, the electrical work alone can exceed the cost of the new HVAC system. Multiply that across a 200-room property and the project either doesn’t pencil or doesn’t happen.

For example, on a recent site visit to a Dallas hotel property, our team found the existing system used a 20-amp breaker. One of our packaged units with electric heat fit that exact load. The general contractor’s response was telling: “As long as we don’t need to replace the breaker, we’re fine.”

On that project, the electrical panel was a bigger concern than cutting a new wall penetration.

The industry is starting to design around this constraint rather than fight it: equipment sized to operate within existing breaker capacity, hybrid approaches that pair electrification with existing infrastructure and right-sized backup heat that doesn’t push the unit into dual-circuit territory.

Think of it the way the lighting industry thought about LED vs. incandescent. The win wasn’t using less light; it was redesigning the fixture so the same outcome cost a fraction of the power. HVAC retrofit needs the same shift. The goal isn’t less conditioning or a workaround; it’s a smarter system that fits the building’s electrical reality and still delivers the comfort tenants expect.

Installation complexity and skilled labor shortages: Even when a system is technically viable, installation complexity can be a dealbreaker, especially in a market facing ongoing skilled labor shortages.

Highly specialized systems that require extensive training, custom fabrication or multi-trade coordination can slow projects down and increase risk. Contractors need solutions that are intuitive, repeatable and easy to deploy across different building types.

Pre-configured systems, plug-and-play components and simplified commissioning processes can dramatically reduce installation time and error rates. When systems are designed with a contractor mindset, they become easier to scale across portfolios.

Cost perception vs. lifecycle value: Upfront cost remains a major consideration, but it’s often misunderstood. Many building owners evaluate retrofit projects based on initial capital expenditure rather than total lifecycle value.

To overcome this, the industry needs to do a better job with the following:

• Quantifying energy savings and maintenance reductions, including the way variable-speed compressors, smart controls and predictive diagnostics extend the life of every component in the system

• Replacing line-item quoting with packaged pricing, so accessories, wall integration and installation labor aren’t hidden costs that emerge mid-project

• Simplifying ROI calculations for non-technical stakeholders. Building owners respond when the cost differential pays back in under five years

• Aligning financing structures with long-term performance, including service models built around remote diagnostics and same-day component swaps

By tying costs to outcomes, these approaches reduce risk for building owners and make retrofit decisions easier to justify.

Tenant experience and downtime: In occupied buildings, tenant experience is often the deciding factor. Even short periods of downtime can lead to lost revenue, complaints or lease complications. In some instances, such as assisted living and nursing homes, downtime is a life-safety issue. Repair and replacement windows in those buildings are measured in hours, not days.

This is why installation speed and operating predictability are becoming just as important as performance.

Retrofit solutions that can be installed in a matter of hours, not days, have a significant advantage. Systems that allow for phased installation, room-by-room upgrades or work during off-hours can minimize disruption and keep buildings operational throughout the process.

Moving forward

In a market where every day a unit sits offline costs money, install speed is becoming the system spec that matters most.

For contractors, the implications across all of these barriers point the same direction: As retrofit becomes a larger share of the market, success will depend on the ability to deliver projects efficiently and with minimal disruption.

That means prioritizing solutions that reduce installation time, evaluating systems based on real-world deployment rather than specifications and building expertise in low-intrusion methodologies.

Future-proofing HVAC one component at a time has stopped working. New technologies arrive every quarter and bolting them onto systems designed a century ago produces clunky, expensive results. To meet the retrofit demand that’s already here driven by energy efficiency goals, regulatory pressure and aging building stock, the industry has to rethink the system as a whole.

The value of this shift isn’t tied to any single product or manufacturer. It’s a broader design philosophy: making retrofit easier, faster and more predictable. It’s how to bring the next generation to buildings whose owners care about longevity, revenue and the experience of the people living and working inside them.

That means rethinking how systems are designed, installed and delivered — eliminating invasive construction, working within existing constraints and prioritizing the realities of occupied buildings.

The good news is that the shift is already underway. New approaches are proving that retrofit doesn’t have to be disruptive, complex or expensive. The next step is adoption.

With a background steeped in technology and building expertise, Trevor Schick brings more than 30 years of operating experience across multiple industries to his role as CEO of AIIR Holdings (https://bit.ly/4ftvSKt).