Include the Ducts in Your Service Agreements

In today’s economic climate, we’re all looking for additional ways to serve our customers. Including duct systems in your service agreements delivers significant comfort and performance benefits to your customer, and to your bottom line.

Adding the ducts to your service agreements is done by taking a few minutes to measure total external static pressure. It’s a small thing that can bring great and immediate results. Static pressure is like a blood pressure test; a quick and painless way to assess overall system performance.

Spring is the perfect time to implement this new service. You can make this change by measuring static pressure on each service call. This test gives you a peek at the airside of the system.  

This simple test, if performed as a part of each service call, will open the door to duct system repairs and renovations that have often prohibited the equipment from operating as it could from the day the system was built.

The change is to pull your head out of the box and look at the system as a whole. By doing this your company will find opportunities to serve that you’ve been walking past for years.

Contractor Benefits
I remember a first-class contractor and I were discussing air diagnostics. (What else do we talk about at NCI?) He summarized the changes in his company over the past few years by saying: “All we used to do was fix the equipment, or replace the equipment. Now, that’s only half of what we do. Now we fix systems, and no one can even think about taking our customers away from us.”

He went on for a half hour talking about building after building that they had “saved,” not only by servicing the equipment, but by going into the ducting and repairing obvious defects that aren’t visible by servicing the equipment only.

His company had recently commissioned a municipal building and turned in a punch list of over 150 items that his service department had discovered. Each was critical to the performance of the system, but was outside of the equipment they had a service contract on. The result was a fat purchase order for the new work they had uncovered. The same opportunities are available in residential systems.

Here’s a list of typical income producing opportunities that can be discovered by adding static pressure to your service agreements. Remember, these repairs may have gone undetected for decades and have been a sore spot to your customers for many years. The gross margins you need to receive for this type of work are in the 60% to 80% range. Don’t think of these as low margin nuisance work, or you’ll never be successful in implementing air diagnostics into your service department.

Static Pressure
It takes less than five minutes to measure total external static pressure. This pressure can then be combined with the fan speed to plot the airflow that the fan is moving. Compare fan airflow to required airflow to evaluate the needed system improvements that increase airflow.  

The pressure drop over a system’s filter or indoor coil can quickly reveal the restriction to airflow of the accessory. This practice proves that filters with excessive pressure drop are one of the top reasons for poor indoor air quality.

Any filter that reduces airflow substantially inflicts a significant energy penalty on that system and needs repair or replacement. You’ll also find that coils that look clean may not be. Compare the actual coil pressure drop to the original manufacturer’s specification to verify cleanliness and take appropriate action.

Measuring pressure in each plenum allows you to check the resistance of the duct system to airflow. Ideally, the supply or the return duct system pressure drop should not exceed 20% of fan rated static pressure. Most duct renovations require the addition of a large return duct sufficient to reduce system static pressure.  

Isn’t it strange that we only service the equipment, and assume the air distribution system automatically remains in tip top shape all by itself?

Rob “Doc” Falke serves the industry as president of National Comfort Institute a training company specializing in measuring, rating, improving and verifying HVAC system performance. If you're an HVAC contractor or technician interested in a free one page procedure detailing how to measure total external static pressure, contact Doc at robf@ncihvac.com or call him at 800-633-7058. Go to NCI’s website at nationalcomfortinstitute.com for free information, technical articles and downloads.