US Air Conditioning News

A Different Retrofit Approach

- June 9, 2020



It’s estimated that over 80% of HVAC retrofit projects only replace the system’s equipment – traditionally, just swapping out the equipment has been considered good enough. But what if there was a different retrofit approach that offers more? What if it allowed you to redesign the system to deliver a superior and more valuable HVAC product?

Simple “Redesign”

The redesign approach to retrofit systems has been used for many years already and is only increasing in popularity among HVAC and mechanical contractors and engineers.

Oftentimes, equipment replacement requires little or no design – many residential and light commercial designers will just use the model number and search for a unit that is the same size as the existing one.

Install contractors will then determine the job details and fabricate or buy transitions to connect the old ductwork to the new equipment, make electrical and gas connections.

Some engineers have little hands-on involvement with projects and rarely interact with their customers, let alone the end-user. A traditional HVAC retrofit project design isn’t really designed at all; it is just to facilitate equipment replacement.

Retrofit System Assessment and Redesign

A retrofit project has an existing system. The opportunity arises to address the issues that may have resulted in early equipment failure and solve long-standing comfort, performance, safety, and health issues. You can also test and diagnose the installed system and build many additional solutions into your project designs.

When the engineer goes above and beyond to complete these steps, they can sell and install badly needed improvements to the system. Customers want the improvements but are not aware of them until they are identified and taught about the benefits.

Does it take more time? Yes. Does it cost more? Yes. Are customers willing to invest more for a better product? Yes, they are, but you must help them understand the products and services that will deliver what they want and need.

There’s another reason some contractors, designers, and engineers take the time to check and upgrade the entire system – new opportunities for themselves and their customers when addressing the entire system. This assures high-efficiency system performance, in addition to high-efficiency equipment.

When using the simplified approach to redesign, the reality is that the system will not perform to equipment specifications because installation conditions often force the equipment to operate outside of those specifications. As a result, the system will not perform the way you promised your customer. Common retrofit design assumptions and corresponding solutions are below.

Assumptions and Solutions

The replacement equipment matches the building loadIt’s well documented many systems operate at half the equipment rated capacity. If the new system is the same size but functions near full capacity, it could be oversized by 50%. Consider downsizing equipment when the design enables the installed system to deliver full capacity.

System accessories function wellWhen system accessories remain, verify the function of each one. Air filters, humidifiers, outside air ducts, heat recovery ventilators, zoning systems, thermostats, or control systems may need upgrade or repair. Address each of these in the system redesign.

The ductwork has the capacity to deliver required system airflowIt’s not uncommon for restrictive ductwork to deliver less than 70% of required system airflow into the conditioned space. Many ducted systems are undersized and overly restrictive. Your redesign can include increasing duct capacity.

Individual room airflow is satisfactoryThis ever-present problem is corrected through duct modifications required in a redesign. Corrections can be made only if the problem is measured and quantified. Increase duct capacity and remove pinch points in the duct system.

The next time a replacement project comes around, budget some additional time and discover additional products and services the system needs and your customers will want in the end.

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