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The New Frontier in HVAC System Design

The New Frontier in HVAC System Design

Those who believe that equipment replacement alone is all that is needed for an efficient installation will continue to miss new opportunities.

When I entered this industry, fortunes were being made in HVAC system design. Today, service companies give away their designs, and mechanical engineering firms are trapped in the treadmill of slapping out gigabytes of production PDF plans. Let’s take a look at what premium services are now being offered to build new value into the HVAC system design and the project oversight segment of our industry.

What Usually Happens

Pre-design system assessment includes a deeper inspection of the air distribution system and some basic testing to assess the actual operating condition of the equipment.

Before investigating these new opportunities, let’s review a typical project from the design perspective. For this scenario we’ll use a 20-year-old light commercial building with five packaged units. The building owner has seen HVAC maintenance expenses almost double in the past three years and the HVAC service company is recommending replacing the equipment.

A typical design job requires creating a full set of plans and specifications that include details of the replacement equipment. This is called the equipment schedule.

Boiler plate code compliance documents and detail illustrations would also be included.

An equipment schedule includes the name of the manufacturer, model number, required airflow, fan motor horsepower, and the economizer model with some basic controls. Perhaps new condensate drains and electrical disconnects would be added.

This type of design has gone on for decades. Designers believed equipment replacement was the only needed efficiency upgrade -- the existing distribution system would last the life of the building.

Is there any wonder this production style design method resulted in little more than a low-bid race to the bottom? The project is void of original ideas, custom solutions, or creativity. Is this type of design even worth the value of its low-bid price?

Pre-Design System Assessment

Those who believe that equipment replacement alone is all that is needed for an efficient installation will continue to miss new opportunities that are available to service companies, mechanical contractors, and engineers. Read more about redefining an efficient installation here.

These new opportunities are built around the idea that to achieve an efficient installation that meets the needs and wants of your customers requires much more work than a little design time and a few calculations on your computer. Spend a small amount of time in the field and really check out the performance of each system you encounter.

Pre-design system assessment includes a deeper inspection of the air distribution system and some basic testing to assess the actual operating condition of the equipment. Less than 3% of distribution systems perform well enough to qualify for a simple equipment replacement. The other 97% are badly in need of additional upgrade work.

Assuming an air distribution system is even functional is the biggest mistake made by 90% of today's designers. Undersized ducting can be detected during a visual inspection and measurement of system static pressures and airflows. It is estimated that 20% of systems have at least one disconnected duct. 

Curbs on packaged units can reduce system airflow up to 50% by overpowering the system fan with resistance to airflow.

By taking time to interview occupants, discover uncomfortable rooms, dysfunctional controls, humidity issues, or other air distribution problems, you can easily make corrections. 

Additional Scope of Work

By delving well beyond the equipment change-out scenario, you open the door to many new opportunities for your business. You will be solving comfort and energy problems your competitors don’t even know exist. And you can create a customer base of raving fans.

Imagine the value to your customers if you look past traditional equipment replacement to discover and deliver solutions addressing long-standing home or building problems that they have endured for years.

In addition to equipment replacement, detail and specify upgrades that will significantly improve both the comfort and efficiency of the system. The most common upgrades include:


  • Installing additional return duct capacity
  • Using higher efficiency, low pressure drop air filters
  • Running additional supply ducts to rooms with low airflow
  • Replacing restrictive fittings and adding duct suspension 
  • Upgrading registers and grilles
  • Adjusting fan speed 
  • Balancing the system
  • Adjusting refrigerant charge or combustion
  • Commissioning new controls.

Going the extra mile to solve hard-to-find problems distinguishes you from the competition and sets you apart from the low-bidders. By using this advanced assessment and design approach and completing the specified upgrades, the final product can be 30% or more efficient and provide far better comfort and performance.

Design Verification

As most designers complete a project and push back from their desks, they imagine a perfectly operating system based on their amazing design.

The reality is that most systems operate at 40% below the rated system capacity listed in the equipment schedule. Ouch! Sorry for the bad news. If you look a little deeper, another opportunity can be found.

The missing link in design is design verification. This can be done by measuring the performance of the system at startup and comparing the design criteria to actual field-measured performance. 

The installation can be actually scored. This is done by measuring airflows and temperatures and calculating the system delivered Btu into the occupied conditioned space of the building. 

By comparing the amount of delivered Btu into the building to the rated Btu of the equipment, you can express the delivered efficiency as a percentage. Just like in school 95% is good, 55% is not so good.

A design not verified is like telling a story that will never come to pass.

This scoring method can be added to the design side of the project and confirm to customers that your design has some teeth to it. A balancing firm or commissioning agent can also provide this service. 

Verification goes beyond balancing or commissioning and provides additional insurance to the system builder that the design actually performs as intended.

A well-operating system outperforms and outlasts the typical system and delivers measurable benefits to occupants for years to come.

These new services can be added to any system design regardless of who provides the design. It always takes extra effort to advance beyond your competition. The invitation is extended for you to upgrade the services you offer your customers. 

Rob “Doc” Falke serves the industry as president of National Comfort Institute, Inc. (NCI), an HVAC-based training company and membership organization. If you're an HVAC contractor or technician interested in a free system scoring procedure, contact Doc at [email protected] or call him at 800-633-7058. Go to NCI’s website at for free information, articles, and downloads.

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