Complete Guide to Curb Adapters

Complete resource on RTU curbs and curb adapters

Curbco strives to provide useful information about installing HVAC RTUs (roof-top units). Whether you’re an experienced contractor or distributor, just starting your career, or just an inquiring member of the general public, you’ve arrived at the only page you need to learn all there is to know about roof curbs and curb adapters.

Let’s start with…What is a curb?

An RTU is an air conditioner– a commercial-grade unit designed to air condition a large space with high efficiency. In the context of HVAC RTUs, a curb is a device used for mounting one of these heavy systems on a rooftop. The curb creates an opening in a roof, separating the roofing material and providing structural support for the equipment that will sit on it.  In an RTU application, the inside of the curb will contain supports where ducts will hang so the air can flow through the roof into the inside of the building.

What is a curb adapter?

Often when an RTU is being replaced, the new unit does not identically match the existing curb size and duct drop locations. Consider this analogy: have you ever upgraded a smartphone, computer, or other device only to find out that your connectors and cables from your old one no longer fit? In a similar way, there has historically been little standardization among the companies who manufacture RTUs and the curbs they sit on. So, units from different manufacturers, and even updated versions of units from the same manufacturer will have widely different footprints and supply/return air configurations.

A curb adapter is a custom-made apparatus that mates the new RTU’s layout with the old RTU’s curb, which remains fixed to the buildings. Curb adapters must be custom made to transition the air from the new unit openings to the old unit openings and to ensure the structural integrity of the whole system. Visit our Curb Adapter Page for specs and features.

What types of HVAC equipment will your curb adapter fit?

Our curb adapters are custom made for your needs. We can build to fit any brand and any size of equipment with the proper specifications. And, our in-house database of adapter designs allows us to instantly provide specs and a quote for any combination of old and new RTUs.

What information do I need to provide to have a curb adapter made?

If you are a distributor, we will need to receive your contact information along with the city and zip we’ll be shipping to.  We will also need to know the manufacturer and model number of both the existing and new units.  All required information can be sent through our online quote page.

Where can you deliver a curb adapter?

We’ve shipped to Alaska, Hawaii, Canada, and Puerto Rico. We can ship anywhere in the US.
We have strong relationships with a few common carriers that handle shipments throughout North America.

When can I get my curb adapter delivered?

Specific delivery times depend on your location, our typical manufacturing time is 2-3 days, but depending on the shipper the delivery time could be from 1-5 days.

How can I order my customized curb adapter?

If you are a contractor, then we can help you find a distributor in your area that we can refer you to. Distributors start by going through our online quote page or emailing or calling 866-469-2240. We look forward to helping you the next time you need to change out an RTU FAST!

How long does an HVAC unit usually last? What are the reasons they are replaced?

RTUs typically have a lifespan of 15 to 20 years. They are usually replaced before the complete end of their lifecycle (around 15 years), and the decision to replace is similar to the one people make when they buy a new car. The unit might still be running, but maintenance on it has become costly and performance may be suffering. An RTU may be replaced out of necessity, or its owner may be after improved efficiency, regulatory compliance (there are new rules surrounding Freon), or may be seeking government incentives for better efficiency (rebates).

What is the difference in quality between curb adapters?

The various manufacturers of curb adapters use materials of different quality and various production techniques. Curbco can confidently state that we use heavier gauge steel than most of our competitors, resulting in a sturdier and more durable end product. We over-engineer our product and likely spend a little more money on materials than other manufacturers.

We make sure to account for features and design attributes that take our curb adapters to the highest possible efficiencies and product longevity. For example, the insulation in the return air cavity within all of our units is “tucked in” around the metal—it’s glued and slotted, and there are no raw edges of insulation exposed in the air flow of our curb adapter. This way, once the RTU is mounted and operational, the airflow doesn’t pull on the insulation, which can result in static pressure and dislodging of insulation.

Our adapters are fully welded and designed for extra structural integrity. We include extra bends in the metal increase the rigidity of the structure, resulting in the toughest curb adapter in the industry. Curbco Tough.

Are some curb adapters brands easier to install than others?

We sometimes troubleshoot calls at the point of installation and discover that people have the curb adapter flipped upside down or turned around. As a result of these experiences, every curb adapter Curbco produces includes a QR code that links to the schematic drawing of the curb. The installer can scan the code using their smartphone and get an installation play-by-play,  decreasing total time to fulfillment.

Curbco also provides lifting lugs which allow installers to lift the adapter perpendicular to the roof. When installing multiple units (we recently fulfilled an order for 50 adapters), these time savings add up in a big way.

If the curb adapter doesn’t fit right when I get on the roof, what is the impact to my costs?

There will be impacts to three main cost centers: contractor time, crane costs (or helicopter costs), and remaking the product if the drawings were prepared incorrectly to begin with. A fourth cost center might be lost productivity ( you can’t help other customers or get new business when you’re tied up fixing mistakes). To avoid costly wasted time, Curbco collects detailed information up-front in order to make the product correctlly and requires a sign-off on drawings we provide. In addition, we encourage our customers to check the product over upon receipt and before moving it onto the roof.

How do you know a curb adapter is going to work?

The best way to ensure the adapter will work as designed is to compare what’s on the roof now to the specs provided by the adapter manufacturer. Validating the adapter manufacturer’s drawings is a mission-critical task which many contractors overlook. Anyone buying a curb adapter needs to ensure that the adapter design isn’t going to interfere with anything on the roof. Consider roof penetration, cosmetic walls built to hide RTUs, conflicts with other vents, and the need for access to panels to be able to service equipment when planning for your adapter installation.

What is the best/worst time of year to replace a curb adapter and why?

The worst time of year would be between Memorial Day and Labor Day, because that’s when all the unplanned maintenance and replacements are happening. It would be wise to proactively plan your RTU replacement outside of the hottest part of the year (the HVAC busy season).

How is Curbco able to offer the best turn times in the industry?

Some firms take on larger projects that take away from their customer experience. Curbco is dedicated to protecting our capacity and providing timely service to our loyal customers, rather than running up wait times to take on huge orders.

In the world of curb adapters, the company which can get it the work done fastest gets the job, so Curbco is obsessively focused on total time to fulfillment and customer experience. We want to help contractors and distributors get more business! When an AC is down, people walk into a place of business and walk right out. The business is losing revenue and time is of the essence.

Here’s our shortlist as to why we’re able to produce curb adapters quickly and efficiently:

  • Careful planning for resources and allocation
  • Decades of experience
  • Blueprints for every possible combination
  • We don’t have to spend any time on design
  • Absolute dedication to brand promises of quick turnaround customer experience
  • Anytime system: Industry-first curb adapter quoting, ordering,and tracking engine
    • Account creation
    • Simple system to provide needed values
    • Drawing notification via email or text
    • Web portal (not document downloads) ensures most current drawing always available
  • Convenience
  • Ease of use
Call Curbco today or visit our quotes page to inquire about your custom curb adapter.