Making Your Business Better

Have you ever driven home at the end of a long day or week, feeling the need for a personal recharge?  Have you ever felt that there must be a better way to run your business?  Have you ever wondered if there are others feeling and experiencing the same things as you?  Of course you have, we all have.  Ernesto Bertarelli, an Italian born Swiss entrepreneur once said, “You can’t change who you are, but you can change what you have in your head.  You can refresh what you’re thinking about, you can put some fresh air in your brain.”  If you want to change what you have in your head and refresh what you are thinking about, you should definitely consider attending Service World Expo in September!  What is that, you ask?


Service World Expo (SWE) 2017 is a veritable learning event and tradeshow fiesta, and it is being held at the Mandalay Bay, in Las Vegas on September 7-8.  SWE 2017 provides learning events for residential contractors on business, management, hiring, and product development.  The tradeshow side of the event showcases cutting-edge products and services in plumbing, HVAC and the electrical home service industries.  What makes the show so special?  Well consider what you will have access to.  (Only a partial list)


 Don’t Forget about The Industry’s Best Tradeshow With the Newest Products and Latest Trends

Don’t Forget about The Industry’s Best Tradeshow With the Newest Products and Latest Trends



Ryan Estis is one of America’s leading business performance experts, and he will talk about the importance of promoting your brand as well as understanding the impact of social connections and technology on your brand.


Traci Brown is a body language and persuasion expert, speaker, author and three-time US collegiate cycling champion.  In this fast-paced keynote, you will learn how to use her system to separate lies from the truth in today’s headlines as well as your own life.  She will tell you how to instantly tell if someone is lying, decipher the important lies and quickly uncover the truth.


J.R. Martinez, American Actor, author, motivational speaker, and retired U.S. Army soldier.  Martinez received burns to over 34% of his body when his Humvee hit a roadside bomb in Iraq.  He will talk about how true potential can only be realized by believing, trusting and not quitting.

General Business Information

– How to avoid theft in your business, by Ruth King.

– Getting reviews your business deserves, by Daniel Lemin.

– Where to spend most of your time, by Adam Thompson.

– Recruiting and leading millennials, by Kenny Chapman.

– Getting a 10 X return on your time, by Allan Ferguson.

– Industry forecast panel, with Vicki Laplant, Jen Anesi, Mike Murphy & Steve Miles.


Service Department Information

– The five blockers of service management success, by Tab Hunter.

– Understanding the minds of technicians, by Nathan Broughton.


Sales and Marketing

– Making more sales in a fair, honest, and dignified manner, by Charlie Greer.

– Selling in the replacement market, by Bill Ligon.

– Web marketing, what works and what doesn’t, by David Squires.

– Making another million dollars by adding more trade lines, by MikeAgugliaro.

– The five step system to generating more qualified leads, by Matt Jones and Will Wang.


This does not include of course opportunities to rub shoulders with industry leaders and top performers.  The value of networking and making new connections for your business often exceeds the cost of attendance just by itself!  This is a Las Vegas bet you will be sure to win, so don’t miss this opportunity to participate in the service industry’s most impactful event of 2017!  Follow the link below for more details.


Service World Expo (SWE) 2017

Golfing for a Cause

Golf Tournament for Joseph Groh Foundation

If you have ever scrolled down through the Callahan Roach website, (and who hasn’t!)  you’ll notice that they support and have a link to the Joseph Groh Foundation.  You may have found yourself wondering who this organization is and what they are all about.  If that is the case, you have come to the right blog!


The Joseph Groh Foundation is a 501©(3) Texas public charity that provides financial assistance to those with a connection to the construction trades industry and who are now living with a life altering disability.  What does “connection” mean?  It means that you have either worked in the trades yourself, or have an immediate family relative (i.e. sibling, child or parent) who has.  What does “life altering disability” refer to?  That could mean many different things, and could be the result of an injury, illness or genetic disorder.  It also means that you are now severely and permanently disabled.  How about “provides financial assistance.”  What does that mean?  That can also mean a number of things.  Unlike some organizations, The Joseph Groh Foundation is not tied to a strict list of items that it will provide.  Their objectives is to work with the individual in order to help provide what they most need.  That is one of the things that makes them unique.  The other is that they are the only 501©(3) organization that we are aware of which exclusively benefits individuals from the HVAC and construction trades.  They do not provide cash however, and benefits are paid directly to the supplier of products and services, not to the recipient.  What kinds of products and services?  Historically, the most requested items have included wheelchair accessible vans, home and bath remodels, assistive technology products and rehabilitative equipment.


How do they raise money for these items?  The primary method is through golf tournaments which they host annually in Dallas, Texas, Chicago, Illinois and Minneapolis, Minnesota.  In fact, the Chicago tournament is coming up on August 28, and the Minneapolis tournament on September 11.  That means you can enjoy a fun day on the golf course, all in the name of supporting a great cause!  It is perfect for sponsorship opportunities, where you can bring customers.  In fact, one major distributor in the Chicago area holds an air-conditioning promotion for their customers, and top performers earn a spot in the tournament.  Therefore, if you are a golf enthusiast and would like to help further this organization’s mission, simply go to their website (address listed below) and click on the Chicago or Minneapolis golf tab.  You will find additional instructions and participation forms there.  Hope to see you in Chicago or Minneapolis!

National Signing Day

Countering a Major Threat to the HVAC Industry

National Signing Day, or National Letter of Intent Day as it is known in some circles, is a noteworthy one.  Not only is it noteworthy for the student athlete, but it is also a big day for their parents, their coaches, and anyone else who has played a significant role in helping the student athlete with this achievement.  For those who may not be familiar with what this is, National Signing Day is the day when high school sports players publicly pledge their allegiance to specific universities.  What does this have to do with the HVAC industry?


I refer you to the ACH&R news article in the June 19 edition, written by Nick Kostora.  Nick’s article highlights the brainchild of Clark Coco, Dean of Washburn University Institute of Technology in Topeka, Kansas.  Clark was looking for an “out-of-the-box” way to get kids interested in the skilled trades that had not been tried before.  Now in its fourth year, National Technical Letter of Intent Signing Day is helping thousands of students achieve their moments of glory in more than 40 schools across the country.  National Signing Day events have been held at schools in Arizona, Kansas, North Carolina, Oregon, Tennessee, Wisconsin, Florida, Alabama, Minnesota, and Oklahoma.


National Signing Day had a remarkable impact on Washburn.  According to Coco, “When I got here, we were referred to as a tired and outdated facility.  We didn’t wear uniforms, we weren’t associated with NC3, (National Coalition of Certification Centers) there were weeds in the sidewalks etc.  Luckily, people really bought into what we were doing.  The school has seen 45% growth in enrollment over the past five years.”


Numerous articles have been, and continue to be written about the need for new talent coming into the industry.  This seems to represent an idea that you can latch onto in your local community.  Local ACCA chapters could set this up with local high schools and trade schools for example.  It is often said the HVAC industry is not very glamorous, but this is certainly an idea that can help it seem more so in the eyes of a young person.  It can help elevate the idea of going into the trades as a realistic alternative to college.  The shortage of skilled workers could very well become the biggest impediment to growth for companies in the HVAC industry in the very near future.  A recent article in BISNOW stated that 74% of construction companies in Texas say they are having a hard time hiring carpenters, electricians or plumbers.  Not only that, the HVAC industry is aging far more than other industries, meaning the average age of HVAC trade workers is older than the national average for other industries.  Ideas like this could very well represent part of the solution to this growing threat.


Countering a Major Threat to the HVAC Industry

Photo courtesy of The Topeka Capital Journal

The Case for Disability Insurance: Part 2

A major disability is something that happens to someone else… until it doesn’t!  The sad fact is most Americans are better prepared to die than they are to deal with disabilities.  In the last blog, we made the case for having disability insurance.  In this blog, we will make the case for affording disability insurance.



The Bureau of Labor Statistics estimates that as of April, 2016 there are about 122.74 million people working on a full-time basis.  According to the chart below, only about 37% of private sector employees are covered by long-term disability insurance.  This would suggest that only about 45 million full-time workers are covered by long-term disability.



According to Kaiser Health News, only 47% of employers offer long-term disability coverage to their employees, and companies with at least 100 employees are almost certain to offer some sort of disability benefit.  Furthermore, they report that the majority of people with disability coverage get it through their jobs.  The chart below offers a glimpse of disability insurance coverage by occupation group.


Access to disability benefit combinations, by occupation group, private industry workers, March 2014
Occupation group Percent with access to both short- and long-term disability insurance Percent with access to only short-term disability insurance Percent with access to only long-term disability insurance Percent with no access to insurance
All workers 25 15 9 51
Management, professional, and related 42 12 17 29
Service 6 14 4 76
Sales and office 25 13 9 53
Natural resources, construction, and maintenance 21 18 6 55
Production, transportation, and material moving 25 22 7 47
Note: Costs calculated from Employer Cost for Employee Compensation (ECEC) published estimates.

Source: National Compensation Survey, U.S. Bureau of Labor Statistics.

The cost of providing both short- and long-term disability insurance access to all private sector workers would be approximately 1.0 percent of total compensation. This would cost an employer $624 each year for a full-time (2,080 hour) worker, as illustrated below.

Estimated cost of access to short- and long-term disability insurance, by occupation group, private industry workers, March 2014
Occupation group Short-term disability insurance Long-term disability insurance
Percent with Access Benefit cost per hour worked Employer access cost per hour worked Percent with Access Benefit cost per hour worked Employer access cost per hour worked
All workers 40 $0.06 $0.15 34 $0.05 $0.15
Management, professional, and related 54 $0.10 $0.19 59 $0.09 $0.15
Service 20 10
Sales and office 38 $0.04 $0.11 34 $0.03 $0.09
Natural resources, construction, and maintenance 40 $0.09 $0.23 27 $0.03 $0.11
Production, transportation, and material moving 47 $0.06 $0.13 31 $0.06 $0.19
As seen in table 6, the cost of access for short-term disability and long-term disability across all private industry workers is $0.30 per hour worked ($0.15 each). The estimate ranges from $0.11 for sales and office workers to $0.23 for natural resources, construction, and maintenance workers. There are no reliable estimates for service workers, which is not surprising given that few service workers have access to employer-provided disability insurance. As a whole, however, the cost of providing both short- and long-term disability insurance access to all private sector workers would be approximately 1.0 percent of total compensation cost ($0.30/$29.99). This would cost an employer $624 each year for a full-time (2,080 hour) worker.

Note: Costs calculated from Employer Cost for Employee Compensation (ECEC) published estimates. Dash indicates data not available or applicable.

Source: National Compensation Survey, U.S. Bureau of Labor Statistics.

Of employers that offer disability coverage 37% paid the entire premium in 2010, down from 49% in 2002.  As of 2011, voluntary programs (meaning the employee pays the full cost) make up 50% of all long-term disability offerings, up from 41% in 2002.  According to the Council for disability awareness, however, when employers add disability insurance as a voluntary benefit, participation is only around 40%.




Counsel for Disability Awareness

US Bureau of Labor Statistics

Kaiser Health News

The Case for Disability Insurance

A major disability is something that happens to someone else… until it doesn’t!  The sad fact is most Americans are better prepared to die than they are to deal with disabilities.  If you are in your twenties, the chances are you rarely think about this.  But you should.  Just over one in 4 of today’s 20-year-olds will become disabled before they retire.In fact, over 37 million Americans or about 12% of the total population are classified as disabledMore than 50% of those disabled Americans are between the ages of 18-64.  At the end of 2012, 8.8 million wage earners representing more than 5% of the entire workforce were receiving Social Security disability insurance, (SSDI) 2.5 million of these were in their twenties, thirties or forties.  But I’m careful, I eat healthy and work out you say.  As it turns out, accidents are NOT usually the culprit.  Statistically, about 90% of disabilities are caused by illness.  Cancer, heart disease and other illnesses cause the majority of long-term absences.  Consider the following statistic for a 35-year-old male.

These costs are immediate, expensive and often not covered by insurance!

These costs are immediate, expensive and often not covered by insurance!

A non-smoking male, 5’10”, 170 pounds, who works an office job with some outdoor physical responsibilities and who leads a healthy lifestyle has the following risks:

  • A 21% chance of becoming disabled for 3 months or longer during his working career
    • Of these, 38% run the chance that the disability will last 5 years or longer
    • the average disability length for this person is 82 months


Similarly, a 35-year-old female weighing 125 pounds has a 24% chance of becoming disabled for 3 months or more during her working career.  As you can see, the chances are simply too great to ignore for the average working person.  Furthermore, most people think that Workers Comp or Social Security Disability insurance will cover their needs if they become disabled.  According to the Council for Disability Awareness, less than 5% of disabling accidents and illnesses are work-related.  The other 95% are not, meaning Workers Compensation does not cover them.  In addition, according to the Social Security Administration, 65% of initial SSDI claim applications were denied in 2012.  The average SSDI monthly benefit payment for males was $1256 and for females was $993, with 93% of all recipients receiving less than $2000 per month.


Given these numbers, how well prepared are American workers for disability?  Not very.  Forty-eight percent of US families do not save any of their annual income, and one third of working families have no retirement savings.  Consider the following chilling statistics.

  • 68% of adult Americans have no savings earmarked for emergencies
  • 65% of working Americans say they could not cover normal living expenses even for one year if their employment income was lost.
  • 38% could not pay their bills for more than 3 months.

So what does the average family do when confronted with a disability?  They begin running up expenses on their credit cards, get a 2nd mortgage, cash in their 401(k) or take out a home equity line of credit and ask family and friends for assistance through sites like go fund me.  As you might guess from the above numbers however, these solutions are inadequate.  According to a Harvard study, 62% of all personal bankruptcies and over 50% of mortgage foreclosures are a consequence of disability, and many end up on Medicaid for insurance.  Keep in mind that while Medicaid rules vary from state to state, the general requirements for income are less than $931 per month and countable assets of $2000 per person, not including your primary residence (with limitations based on your home equity), personal property and household belongings and up to one motor vehicle.  ($3000 per couple living in the same household)


What is the answer then?  Disability insurance!  How common is it?  Consider:

  • 65-70 % of workers in the private sector have no long-term disability insurance
  • That equates to about 75-80 million private-sector workers who are without long-term disability income insurance
  • Worse yet, only 46% of workers have even discussed disability planning


Next Blog: Access To And Cost of Disability Insurance



American Journal of Medicine

US Social Security Administration

Counsel for Disability Awareness

US Federal Reserve Board

American Payroll Association

Get Sick, Get out: The Medical Causes of Home Mortgage Foreclosures

Memorial Day

Memorial DayOh that first long weekend of the year!  Memorial Day marks the unofficial start of summer, and it’s mere mention conjurers up thoughts of picnics, parades, grilling out and adventure travel.  Pretty much everyone knows that Memorial Day commemorates those who have given their lives in service to their country.  But do you know the history of Memorial Day?


The practice of honoring those who have fallen in battle actually dates back thousands of years.  The ancient Greeks and Romans held annual days of remembrance for loved ones killed in battle, festooning their graves with flowers and holding public festivals and feasts in their honor.  One of the first known public tributes to war dead was in 431 BC, when the Athenian general and statesman Pericles delivered a funeral oration praising the sacrifice and valor of those killed in the Peloponnesian war.  (An ancient Greek war fought by Athens against the Peloponnesian league led by Sparta)


In this country, Decoration Day as it was originally known, dates back about 150 years.  In 1868, Gen. John Logan issued a decree that May 30 should become a nationwide day of commemoration for the more than 620,000 soldiers killed in the Civil War.  According to legend, Logan chose May 30 because it was a rare day that didn’t fall on the anniversary of a Civil War battle.  Logan Circle in Washington, DC is named in honor of this general.  By 1890, every former state of the union had adopted it as an official holiday.  But for more than 50 years, the holiday was used to commemorate just those killed in the Civil War.  It wasn’t until World War I that the tradition was expanded to include those killed in all wars, even though Memorial Day did not become a federal holiday until 1971.


The term Decoration Day was used for more than a century until it was changed to Memorial Day by federal law.  In 1968 Congress moved Memorial Day from May 30 to the last Monday in May.  Did you know that Memorial Day has a “birthplace”?  In 1966 President Johnson signed legislation declaring Waterloo, New York as the official birthplace of Memorial Day.  In 2000, Congress passed legislation encouraging all Americans to pause for a national moment of remembrance at 3 PM local time.  So this Memorial Day as you are enjoying all the festivities of the holiday weekend, take a moment to think about those who served and sacrificed to make it possible!


Source: The History Channel


I pray that our Heavenly Father may assuage the anguish of your bereavement, and leave you only the cherished memory of the loved and lost, and the solemn pride that must be yours to have laid so costly a sacrifice upon the altar of freedom.

Excerpt from letter written to Mrs. Bixby of Boston, Massachusetts by Abraham Lincoln on November 21, 1864, after two of her sons were killed in battle.


Could Energy Star Be Eliminated?

Could Energy Star Be Eliminated?Unless you have been living under a rock, you have almost surely heard of a program called Energy Star.  A recent industry publication cited a statistic that as of 2016, 91% of US households recognize the Energy Star label.  Beyond mere recognition however, what is Energy Star and how does it work?  Energy Star is a program established by the EPA in 1992, and it sets energy efficiency standards for appliances, electronics, houses and buildings.  It’s not a regulation however, as businesses decide on their own whether or not to design products that comply with the standards.  So, what’s my point?  Early reports indicate that the 2018 budget of the Trump administration may reduce the EPA’s budget by 31%, eliminating nearly 4000 jobs.  One of the programs rumored to be cut as part of this reduction is the Energy Star program.  Is that a good idea?


There is much agreement that the rate and volume of rule promulgation by the EPA in recent years has added cost and questionable benefit for consumers as regards the development of HVAC equipment.  Energy Star is different however.  Instead of compelling business to adopt specific energy efficiency standards, it seeks to encourage by promising recognition and consumer support.  The theory is that consumers seeking to purchase energy efficient products will rely on labels such as Energy Star to help guide their choices.  According to Energy Star, the program has been extremely successful.  They report that since its inception, Energy Star has helped families and businesses save $362 billion on utility bills while reducing greenhouse gas emissions by 2.4 billion metric tons.  In addition, about 1.8 million Energy Star certified new homes have been built.  What do HVAC companies have to say about all this?


Two HVAC contractors recently interviewed by the ACH & R News didn’t believe that their businesses would be hurt much if the program was to go away.  On the other hand, one felt its disappearance would negatively impact the HVACR industry.  Steve Lauten of Total Air and Heat in Plano said, “It gives incentives to provide air-conditioning systems that deliver installed efficiencies versus rated efficiencies… particularly in residential and new home construction.  Energy Star means the duct system is sized and sealed like it should be and it means that equipment is checked out and charged like it should be.  Energy Star provides some level of confidence for consumers and ensures they are making good decisions.”  Conversations with contractors in the article seemed to imply that the more your company talks to the consumer in terms of total building efficiency and installed versus rated efficiency, the less they might be impacted by the elimination of this program.  For the tens of thousands of contractors however who sell on the basis of rated efficiency and labels like Energy Star, the programs elimination could prove harmful.  What about manufacturers?  According to the article, a recent Associated Press report stated that more than 1000 US companies, including United Technologies and Ingersoll-Rand have urged government officials to preserve the program, stating it should be strengthened, not weakened, to encourage energy conservation.  One of the contractors in the article summed up his feelings this way.  “Cutting out something like Energy Star simply to save money is not doing the right thing for the country.”


Information cited from May 15, 2017 ACH R news and March 23 Washington Post

Individualized Comfort

Have you ever walked into an office building and seen electric heaters on the floor by people’s desks?  Even worse, have you walked by an office and noticed cloth or cardboard stuffed into the diffuser?  That’s a clear indication of comfort problems.  A person is thermally comfortable when their bodies heat loss equals their heat production.  People vary, so what is comfortable for one individual is not for another.  What’s the solution?  Oftentimes a contractor will recommend installing airflow dampers in or rerouting ductwork.  More times than not, this results in an unsatisfactory solution.  How else can you correct the problem?  One way is with a VAV diffuser.


Individualized Comfort

Titus model T3SQ shown above, providing a view “above the ceiling.” The black device is the wax filled actuator. When the wax heats up, it causes the arms to rise, thereby listing the damper and allowing more airflow. When it cools down, the arms relax thereby lowering the damper. The minimum airflow adjustment ring can be seen in the center of the actuator, and the heating and cooling setpoint adjustment rings are found in the top half of the actuator.


What is that you ask?  Simply put, a VAV (variable air volume) diffuser is one which modifies airflow to the space based on a thermostat controlled by the user.  In other words, in a space heated and cooled by a rooftop unit, individual offices or spaces can have their own diffuser and their own thermostat.  If more than one third of the load is controlled by these diffusers however, a dump zone must be maintained in order to avoid damage to the compressor.  So for example, on a 5 ton unit, (2000 CFM) a dump zone must be maintained if more than 600 CFM is being controlled by VAV diffusers.  How do they work?


Using an architectural Square plaque ceiling diffuser, manufacturers incorporate a wax filled thermal element attached to the top side of the plaque.  (See picture) There are no wires involved.  This thermal element gets its room air temperature reading via a sensor mounted in the center of the diffuser.  The sensor allows for no more than a 1°F dead band between the induced room air temperature measured by the sensor and that of the zone air being supplied to the diffuser.  If the space begins to heat up in the cooling mode, wax in the thermal element also begins to heat up, thereby raising up the damper in the diffuser and allowing more airflow into the space.  As the room sensor become satisfied, the wax in the thermal element begins to cool down and the actuator assembly lowers, thereby reducing airflow to the space.  At least one manufacturers design allows the user to adjust the minimum airflow of a satisfied diffuser anywhere between 0-30%.  This capability allows the control necessary to meet Ashrae Standard 62.  Furthermore, these diffusers are listed by AHRI, so their rated performance has been tested by a certified lab.


What does this mean for the astute contractor?  Simply put, opportunity!  Consider the following statistics.

  • Thermal comfort is the most often cited complaint in office buildings today
  • Studies have linked improved comfort to reduced absenteeism, and thereby improved productivity
    • Labor costs are typically 10 times that of a property, so an improvement in comfort is rewarded with large returns in productivity


In a commercial building setting, awareness of the technologies that have a measurable impact on personal comfort and therefore productivity can help your company become the contractor of choice for problematic applications.


Picture courtesy of Titus

Those Dirty Grilles – Part 2

In the previous article, we talked about terminology and the difference between a diffuser, a grille and a register.  In this article, we are going to talk about dirt streaks on the ceiling, their causes and solutions.


The Titus TMS diffuser – the world’s 1st anti-smudge diffuser! Invented by Titus in 1955 to accommodate the trend toward acoustical lay in ceilings needing a square diffuser with a radial air pattern.


We have all seen restaurants or office buildings where the ceiling has become smudged and dingy with dirt streaks running across the ceiling next clearly coming from the air outlet device.  Most people assume the cause is dirty filters or dirty air within the space.  While they are contributing factors, there are several others which most contractors will not think about.  Fixing this problem when other contractors have not been able to could bring you a long-term customer!  So what are those other factors?


The first thing to look at are the air outlets (assume they are diffusers) themselves.  Have they been properly chosen for the application?  Believe it or not, diffusers are more than just “hole covers.”  Perhaps future articles will tackle the discussion of air inlets/outlets and their general applications, because the scope of this discussion is beyond this article.  You would be well served however as a contractor to take an application class from a trusted industry source such Hart & Cooley or Titus.  Bear in mind, proper diffuser selection cannot only impact dirt streaks but also sound levels within the space.


The second thing to keep in mind is the duct system leading to the diffuser.  Are the duct air velocities appropriate or is there a restriction somewhere?  It is not uncommon for example to find a situation where the round duct is kinked as it enters the top of the diffuser.  If there are restrictions, outlet velocities will be much lower than they should be, causing induction with room air as soon as it leaves the diffuser.  If you find this to be the case, there are companies that offer a brace designed to shape flexible ducts into highly efficient 90° elbows at the diffuser inlet.  When room air mixes with supply air at the outlet of a diffuser, not only will the system perform inadequately but you could also smudge the ceiling.


The third thing to keep in mind are the jet characteristics in the four zones of expansion for a diffuser.  As air leaves an outlet device, four distinct zones of expansion define the jet of air.  Jet velocities from a ceiling diffuser can be measured outward from the discharge point of the device.  The first zone which is closest to the outlet of the diffuser extends approximately 1 ½ duct diameters from the face of the diffuser, and is characterized by a constant velocity with minimal mixing of supply and room air.  In other words, a properly designed air distribution system will not induce room air within 1 ½ duct diameters.  For example, if the diffuser is being fed by a 7 inch round duct, there should be no room air mixing with the supply air within the first 10-12 inches.  In the second zone, the jet of air begins to mix with room air, and the resultant induction causes the jet of air to expand.  Velocities may well exceed 150 ft./m in this zone, depending on the design and application.  The third zone is where most of the induction occurs, and is the most important zone because it has the most effect on room air velocities and room induction.  Velocities at the edge of this zone may run between 50 ft./m(considered terminal velocity) and 100 ft./m.  The fourth zone is the one with relatively low air velocities.  Typically, air will reach terminal velocity in this zone.


Understanding the science and principles of air distribution can be a point of marketable differentiation between you and your competitors!


Photo courtesy of Titus.

Those Dirty Grilles

A grill + a damper = a register!

My pastor writes a weekly blog, and recently he mentioned a life experience where he was completing the wiring of a new Nest thermostat as part of a DYI project to make his home more energy efficient.  He said he was feeling self-assured as he connected the power wire to the thermostat from “the heater,” but later that night awoke to a cold house.  While I found it interesting how he made the connection between an HVAC project and the Almighty, that is not the subject of this blog.  I did find a part of it worth discussing however, and that is the topic of terminology.

I responded to my pastor that it was a great article, but that as a member of the HVAC community, I had to let him know that from a terminology perspective, the wire was actually coming from his furnace, not the heater.  Similarly, have you ever had someone walk into a room, look up at the ceiling and say something like, “Wow, those grills are really dirty.  They need to change them.”  That statement is just wrong on many levels.


Let’s first address the term “grilles.”  A grill is something you cook on and a grille is an air outlet or inlet device.  You would not want to cook on a grille, as it would leave funny looking sear (not to be confused with seer) marks and likely impart the taste of cooked paint to your food.  While we are on the topic of grilles, let’s clarify once and for all what the differences are are between air inlet and outlet devices.  (ASHRAE’s term)  Grilles can be used on both the supply and return air side of the system, and are technically described as a device whereby the inlet and outlet area, size and shape are generally the same.  In general, a grille is also a device where the general direction of the air coming from the ductwork is not changed after passing through the grille.  Adding a damper to a supply air grille makes it a register.


A diffuser is a supply air (only) device that is used to achieve specific objectives related to airflow patterns and mixing.  More specifically, a diffuser is an air outlet device in which the inlet and outlet area size and shape are generally not equal.  In addition, the direction of air leaving a diffuser usually changes from the direction in which it is traveling when it leaves the ductwork.


Whew, I’m glad we cleared all that up.  What about the comment related to dirty grilles and the need to change them?  Read next week’s blog and we will tackle that statement.  Meanwhile, I need to go check the setting on that automatic ambient air setpoint control device!


Picture courtesy of