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August 16, 2017
When thinking about opportunities for professional HVAC contractors as our industry turns its attention to the upcoming air conditioning season, I took a quick look back at an article titled High Performance, Green Air Conditioning I wrote in April of 2008. As a fellow who always likes to think about change, I was struck by the number of changes that have occurred in our industry in those short 7 years that present great new win-win opportunities for contractors and homeowners. I am sure each reader will have their own list of specific product features that make new AC systems more efficient, quieter and more durable, but I want to outline five.
First, but in no particular order, would be duct sealing. In the 2012 Ontario Building Code there is a new requirement that all transverse joints of sheet metal ducts be sealed. This is referred to as a Class C seal level in accordance with the SMACNA, "HVAC Duct Construction Standards - Metal and Flexible". In testing a few duct systems, done in production housing, we have found that the typical duct leakage under this new requirement falls in the range of 10%-15%. This is a significant improvement over the 25% to 35% leakage of a standard sheet metal duct system that we have measured in hundreds of systems in the last 20 years. Most importantly in these new, sealed systems we found that it was far easier to balance or change the airflow from room to room. Finally, it may be possible to actually drive more cool air to upper floors. Of course, that's just in Ontario and just new homes, so the real opportunity in existing houses is the new-to-Canada aerosol duct sealing system that I have written about before. This spring and summer assess the performance of the air distribution systems of the houses you service and recommend duct sealing as appropriate. To do this, test duct pressures, velocity at selected outlets and overall duct leakage. Thousands of professional HVAC contractors in the U.S. have and use duct leakage testing equipment; in Canada I can say with authority it would be less than a dozen or two contractors that can thoroughly assess duct leakage and the resulting opportunities for improvement.
Next, lets be reminded that in the last seven to ten years low emissivity coatings on windows has become the norm, if not a code requirement, in both new construction and in the replacement window industry. This is significant because windows can account for as much as 40-50% of the total sensible cooling load and the solar heat gain of commonly available windows can vary from at least 0.25 to 0.6. This means new opportunities for properly sizing air conditioning systems. Indeed, to properly assess the air conditioning needs of homes, knowing windows and window coatings better would give you a head start. For less than $400 you can buy a test device to determine the solar heat gain characteristics of in-situ windows and thus enhance your professional standing with cool-conscious customers.
Controls opportunities have also exploded over the last seven years. For example, it was 2007 when the first practical WiFi enabled thermostat, the EcoBee, was introduced and now, of course, there are many such devices available - some designed for the professional contractor and some lighter duty retail versions. Don't let this opportunity get away from our industry. Specifically related to the air conditioning market, the leading controls offer great features for HVAC contractors and their clients. In my mind the most important is the monitoring capabilities. More and more, clients are going to want you, even expect you, to monitor their systems remotely for them. Imagine, if last summer you had installed and monitored a WiFi enabled thermostat for a client and this year it happens they need a new air conditioner. Now you could retrieve last years AC run times, RH levels and temperature profiles. You are now in position to far more accurately size the overall system, but also present ideas for better humidity control - whole-house dehumidifiers, ERVs or variable speed fan motors and compressors to adjust the sensible to latent performance of the AC system. Rather than competing with six other contractors for a 3 Ton sale, you can offer a comprehensive comfort solution based on your clients specific needs. And that's just the AC opportunities related to the monitoring capabilities of these new controls. Since the EcoBee was introduced, they and other more recent entries, have included many other helpful diagnostic and control enhancements that impact air quality, energy efficiency and equipment durability.
In staying with the air conditioning theme, it may be useful to remember that AC loads are typically far more variable than heating loads. The intermittent nature of solar gain and internal, occupant loads represent a much higher percentage of the total AC load than the typical heating load in the same house. There are new, or at least more commonly available technologies, techniques and technologies available now to manage or target these intermittent and variable loads. I am thinking specifically of the popularity of variable speed fan motors and 2 stage air conditioners that make it easier to install duct-zoning systems. In the past, a big barrier to retrofitting duct-zoning systems was the complexity of by-pass air. Being able to modulate airflows and cooling capacity more effectively makes zoning far less complex. That combined with the enhancements of the leading zoning companies, like plug-and-play controls, insert dampers and wireless temperature sensors means zoning should be on every contractors list of comfort solutions for every more discerning clients. Of course, the profusion of reliable, now main stream ductless or mini-split cooling options is another viable way to manage intermittent or isolated cooling loads.
As you get into the 2015 air conditioning season, remember most of your clients are way beyond those simpler days of just opening the fridge door or sleeping in the basement to get a little cooling. They are expecting and are willing to pay for much finer degrees of cooling comfort, something that meets their specific needs. Their 200 cubic foot SUV probably has at least 3 cooling zones, we should be able to do better than one system, one control for their 30,000 cubic foot home. Fortunately we can do better testing and monitoring to determine specific needs and we have zoning, dehumidification, ventilation, variable output, sealing and control techniques and technology opportunities to offer. No doubt there are many more that the creative, professionals readers of this magazine have to meet the ever-increasing expectations of homeowners.