Simple and Helpful

Before Warren Lupson assumed his role as the AHRI director of education, he was a contractor who owned his own business for 28 years and participated on ACCA manual committees for 32 years. Speaking as a contractor, he always found Manual S to be very helpful.

“I was a firm believer for many years in doing dual fuel applications, and Manual S helped me pick the economic balance point on my dual fuel systems,” Lupson says. “It helped me know when to lock the heat pump out and bring a fossil fuel device in.”

According to Lupson, contractors who follow Manual J, Manual S, and the ACCA Quality Installations Standards will lead the way in the movement toward “green” energy-efficient buildings. “I'm happy to see Manual S adopted into the code, but on a personal basis I think, whether it's code or not, it's just the right way to go about designing a system.”

Following Manual S is a simple process, Isaac adds. “And in the end, homeowners will be safer, healthier, more comfortable, and save more energy when the right size unit is selected,” he says.

Wes Davis is the manager of technical services for the Air Conditioning Contractors of America (ACCA). He wrote “Bob's House” — a case study in the proper design of a residential HVAC system — and coordinated the development of the Quality Maintenance Standard and the Quality Installation Verification Protocols. Davis was a licensed HVAC contractor who holds several NATE certifications. He can be reached at 703/824-8847, e-mail Wes.Davis@acca.org. Ron Rajecki is a contributing editor to Contracting Business. He can be reached at 440/979-0667, e-mail ron.rajecki@gmail.com

Why OEM and not AHRI?

The Air-Conditioning, Heating, and Refrigeration Institute (AHRI) produces the standards for rating various heating and cooling equipment. Manufacturers are responsible for testing and certifying the performance of their heating and cooling equipment to these standards. After equipment is tested in accordance with the appropriate standard, the original equipment manufacturer (OEM) data is published in AHRI product directories (ahrinet.org).

However, the certification and efficiency data that appears in the product directories should not be the sole source that contractors use to select heating and cooling equipment. The test conditions AHRI uses, based on U.S. Department of Energy mandated requirements, simulate a limited geographic area in the U.S. This restricts the use of these data. Therefore, per Manual S, the OEM expanded performance data should be used to select the properly sized equipment, and AHRI directories should be used to compare relative equipment efficiency ratings.

For More, Here's Manual S In-depth

For an in-depth look at how to apply Manual S from the Air Conditioning Contractors of America, check out Wes Davis' article, Sizing Equipment According to Manual J is … Wrong! An Introduction to ACCA Manual S, the full text of which can be viewed at ContractingBusiness.com/ManualS. This article includes charts, tables, definitions, and provides a step-by-step example of using Manual S to select equipment for both heating and cooling applications.