Imagine a scenario where homeowners purchase a new washer and dryer for their home. They’re excited for the presumed improved energy efficiency and quicker drying times.

But after installation, they discover it still takes way too long to dry the clothes. For some, this may be a 45-minute cycle or possibly running the dryer twice to get those towels nice and dry.

This scenario happens every day simply because building codes have not yet regulated the efficiency performance of the entire dryer vent and the roof terminations used. 

So what does the building code reference to ensure the dryer is venting efficiently? Section M1502 of the code requires: transition ducts cannot be longer than 8 feet; terminations must have a back-draft damper; total developed length should be less than 35 feet; and screens cannot be used at the termination point. The code also notes that dryers shall be exhausted based on the manufacturer’s instructions. 

Breaking with tradition

Traditional roof terminations available in big-box stores meet current code regulations, but pay no attention to the efficiency requirements of dryers. On average, appliance manufacturers require dryer exhaust systems should not exceed 0.67 water column inches of pressure. Higher pressure levels create longer cycle times, accelerate lint buildup, violate design limitations and may even void the warranty. 

Common 4-inch “gooseneck” terminations generate 0.65 wci, which may already be pushing the limits on the manufacturer’s instructions. In fact, nearly all popular roof exhausts have poor or very poor efficiency as found in a testing lab using a Magnehelic gauge and a real dryer. Technically, straight pipe adds 0.01 wci per foot and every elbow adds 0.10 wci. This means a home with a 27-foot run (vertically plus horizontally) and two elbows creates a total of 0.47 wci. Any roof termination creating more than 0.18 wci creates a real threat that goes against the manufacturer’s recommendations. 

Without having strict code regulations in place for roof termination performance, it becomes imperative to educate the HVAC industry, roofers and vent technicians on the importance to install and maintain an efficient dryer roof exhaust. 


The new DryerJack series of roof terminations from Florida-based In-O-Vate Technologies Inc. was designed to solve the problem, officials with the Florida-based company say. 

The DryerJack was designed with three main goals in mind: 

Provide a roof termination with the industry’s most efficient airflow design

Allow for duct cleaning accessibility

Deter bird or rodent entry. 

During lab tests, both DryerJack models added less than or equal to 0.01 wci — achieving what company officials say is an unprecedented level of performance on a product that has not changed for decades. 

The reason for DryerJack’s airflow results is the curved damper resting on a hinge pin within the galvanized steel body. Between Model 466 and the higher-profile Model 486, the DryerJack series can accommodate nearly every slope and roofing material that’s popular in the United States. To increase the longevity and aesthetics, customers can choose powder-coated options in brown and black as well. 

A number of HVAC suppliers and numerous roofing companies have already adopted the DryerJack for both new construction and reroof opportunities. 

Mike Bice, owner of BBC Roofing of Lake Worth Inc. in Lake Worth, Fla., has seen good results selling and installing DryerJack over the past year. 

“Selling roof terminations for a premium has historically been difficult since my customers can go to big-box stores and see the same item at a fraction of my ‘installed’ price,” Bice said. “With the DryerJacks, I’m able to add value to the sale through its airflow performance while yielding higher profit margins because they are not available locally to the end user.”  

This article and its images were supplied by In-O-Vate Technologies.