Many people worry about the possibilities of getting some flu like symptoms from the aircon unit. If you want to learn more about this fact, you should keep reading this article. There are some important things that you need to know about the correlation between air conditioning and flu like symptoms. There are some factors that can trigger the development of some health problems in most users. You should take a look at these factors, so you can use your air conditioning without having to worry about getting some health problems in the future. Here are some factors that can result to the flu like symptoms.

1. Dirty air filter
This is the first factor that can trigger the development of some flu like symptoms. If you want to stay fit and healthy when staying in a room with air conditioner, you should clean your air filter regularly. This filter should be cleaned regularly, so you can remove some impurities from your aircon unit. There are some unwanted things that may accumulate in your air conditioning, for example dust, dirt, sand, microorganisms, and some other contaminants. These items can cause some health problems in some sensitive people.

2. Too cold temperature
If you don’t setup the temperature of your air conditioner, you are going to get too cold temperature from your aircon. This cold temperature can cause some health problems in some people. Some people are suffering from flu like symptoms, such as fever, headache, runny nose, and some other health issues, especially when they stay in very cold room. It is recommended that you setup the thermostat of your aircon unit before you turn on your air conditioning. It is recommended that you use normal room temperature, so you can avoid getting some health problems from cold temperature effectively.

3. Water leakage
This is another problem that can occur in your air conditioning unit. This problem can be caused by the blocked drainage system in your aircon. This problem should be treated properly. The water leakage problem can accumulate some microorganisms, including influenza virus, molds, and some other bacteria. If you leave this problem untreated, you are going to develop flu like symptoms very quickly. Some of these microorganisms can attack you and your families, especially if you spend a lot of time around this water leakage. You should fix this problem immediately, so you can reduce the possibility of getting flu symptoms in your daily life.

4. Strong wind
Most aircon units can be controlled easily. You should be able to monitor and control the wind strength level from your unit. If you don’t control the wind level, you can have strong wind from your air conditioning unit. This strong wind can cause some flu like symptoms in certain people. If you want to stay fit and healthy in your daily life, you should consider setting up this wind level properly. You should be able to avoid some flu-like symptoms by controlling the wind production in your aircon unit. It is recommended that you use low wind setting for staying comfortable in your room.

5. Frozen coil
This is another common factor that can trigger the flu like symptoms in certain people. This problem can affect the overall airflow system in your unit. It reduces the capability of your air conditioning unit for removing dirty air from your room. If your aircon unit cannot produce good airflow in your room, you may have difficulties in getting fresh air. This is the another reason why improper air conditioning unit can cause serious health problems or other flu-like symptoms. It is recommended that you replace the frozen coil with the new one. You can also remove some objects that can block the airflow in your aircon unit.

They are some common factors that can lead to the development of some health problems. It is recommended that you maintain the quality of your air conditioning regularly. Make sure that you do some regular maintenance procedures, so you can use this unit for a long time. It is important to know that most air conditioning units are safe for most people today. There is no significant side effect that can be cause by this unit. You should be able to have healthy and fit body when you stay in your room with air conditioner. Call a professional company for servicing your aircon units regularly.


The need for preventive building HVAC maintenance will always provide opportunity.

The most recent session I attended on this topic was during the recent Mechanical Service Contractors Association conference. About 200 attendees packed a room to hear from three of the industry’s best PM proponents: David Bavisotto, vice president, service with Illingworth-Kilgust Mechanical; Steve Smith, senior vice president, ACCO Engineered Systems; and Jon Finch, vice president, training and recruiting, Milwaukee Tools.

This power trio framed their presentation around the idea that times and technologies continue to change, but the need for preventive maintenance remains a constant opportunity.

We’ve gone from color-coded dispatch boards and a $30/hour service rate in the 1970s, to beepers, pagers, two-way radios, and up to today’s cell phones and tablets, with labor rates of well above $120/hour.

Service offerings have also expanded, with value-adds like thermal imaging, vibration analysis, energy services, and energy service agreements. GPS has helped to streamline pre-planning and improved vehicle tracking. R-22 is disappearing. Micro-channel coils need less refrigerant, and the popular building protocols Lon and BacNET provide unlimited access to control systems. Offices have became paperless or close to it, and the smartphone is king. And have you looked into drones yet?

These improvements have all contributed to the contractor’s need to service existing (and aging) buildings.

“The service business is absolutely one of the key businesses to be in,” Bavisotto said, because, guess what? People need heating and cooling, in every economy.

The median building age is over 32 years, and half of all commercial buildings were built before 1980. Sixty-one percent of construction projects are retrofits.

“In 2012, the amount of commercial office space exceeded 87 billion square feet,” Bavisotto said. “As these buildings age, there are more opportunities for service providers.”
Why would you, as a commercial mechanical contractor avoid this sure thing?

Another key fact they shared is that 50 percent of all buildings in the U.S. are 5,000 sq. ft. or less. “For this vast amount of customers, we just see the service business doing nothing but increasing,” Bavisotto said.

The biggest line item in the lifecycle of a building is alteration, energy and operation, at a whopping 75 percent.

Steve Smith said ACCO Engineered Systems began to attack the service market in the 1990s, after participating in a peer group meeting, whose other members had all adopted a maintenance

“Their profitability was double ours,” he said, “so we decided to invest in maintenance. We made that a mission over time. If not, we would have continued to be victimized by the ups and downs of the retrofit market.”

Service contracts provide an inside track into the customer’s eventual retrofit work and pull-through work. Planned maintenance is the lowest risk method to grow your service, and the fastest way to build a service business, at low risk/high margin terms.

Finch took the room through a rough look at market concentration: are you most active in hospitality, institutional, commercial building or manufacturing? And is that comprised of new business or retrofits? Where do you spend most of your time?

Time for this presentation was limited, but the message was clear. “Take the time when you get home, to develop metrics to know what markets you’re in, what is your return, and where you want to go,” Smith said.

“With planned maintenance, you control the when, where and how. It’s the fastest way to grow a service business,” Bavisotto said. And, it positions your firm as the go-to source for additional work.


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The history of trying to keep cool in extreme temperatures is a long an interesting one – from slaves cooling royalty with palm fronds, to the latest digital air solutions which feature Wind-Free™ technology.

Modern air conditioning relies on the process of evaporation to cool and humidify the air at the same time. While this concept is constantly being improved upon, its roots extend back to ancient *Egypt, where reeds were hung in windows and moistened with trickling water. When wind blew through the window, the water evaporated and helped to bring down the searing Saharan heat. Later, in ancient Rome, water from aqueducts were circulated through the walls of some homes to cool them. In medieval Persia cisterns and wind towers were used to cool buildings during the hot season.

The first air conditioner resembling the system we know today was installed in a home in the United States of America in 1914. Inventors’ understanding of scientific principles had grown in leaps and bounds between ancient Egypt and early 20th century US. The principle of evaporation remained intact, but the process was now achieved by driving air through water-cooled coils.

A little over a century after this invention, air conditioners are widely in use across the globe, in homes, businesses and cars. Most of the air conditioning systems in use today still rely on these methods.

Samsung’s new Wind-Free™ Cooling technology represents a revolutionary shift in the way air conditioners work to make our lives more bearable. It has been designed to optimise airflow to bring new levels of comfort to our daily climate control requirements. Samsung’s new air conditioners, which feature Wind-Free™ Cooling technology provides consistent temperatures without directly blasting users with air or creating unpleasant cold spots, offering value that you can feel at home and on your electric bill.

“Samsung uses its global network and innovation to create positive change for people across the world. We use design and innovation to provide people with new experiences and aspirational products such as Wind-Free™ technology,” says Mike van Lier, Samsung Director Consumer Electronics.

In its vision of Wind-Free™ Cooling technology, Samsung aimed to create an air conditioning system that does not rely on strong blasts to cool a whole room. This required new ways of thinking about how the appliance vented air and regulated the strength of its breeze. The result: an air conditioning system that maintains consistent and ideal temperatures that keep them comfortable all day and all night, while also keeping its cool with the environment through a serious cut in energy expenditure.



Bahadori, M. N. (1978). Passive cooling systems in Iranian architecture. Scientific American, 238(2), 144-155.


Source:South Africa Newsroom

In air conditioning, heating and ventilating work, it is helpful to understand the techniques used to determine air velocity. In this field, air velocity(distance traveled per unit of time) is usually expressed in feet per minute (FPM). By multiplying air velocity by the cross section area of a duct, you can determine the air volume flowing past a point in the duct per unit of time. Volume flow is usually measured in cubic feet per minute (CFM).

Velocity or volume measurements can often be used with engineering handbook or design information to reveal proper or improper performance of an airflow system. The same principles used to determine velocity are also valuable in working with pneumatic conveying, flue gas flow and process gas systems. However, in these fields the common units of velocity and volume are sometimes different from those used in air conditioning work.

To move air, fans or blowers are usually used. They work by imparting motion and pressure to the air with either a screw propeller or paddle wheel action. When force or pressure from the fan blades causes the air to move, the moving air acquires a force or pressure component in its direction or motion due to its weight and inertia. Because of this, a flag or streamer will stand out in the air stream. This force is called velocity pressure. It is measured in inches of water column (w.c.) or water gage (w.g.). In operating duct systems, a second pressure is always present. It s independent of air velocity or movement. Known as static pressure, it act equally in all directions. In air conditioning work, this pressure is also measured in inches w.c.

In pressure or supply systems, static pressure will be positive on the discharge side of the fan. In exhaust systems, a negative static pressure will exit on the inlet side of the fan. When a fan is installed midway between the inlet and discharge of a duct system, it is normal to have a negative static pressure at the fan inlet and positive static pressure at its discharge.

Total pressure is the combination of static and velocity pressures, and is expressed in the same units. It is an important and useful concept to us because it is easy to determine and, although velocity pressure is not easy to measure directly, it can be determined easily by subtracting static pressure from total pressure. This subtraction need not be done mathematically. It can be done automatically with the instrument hook-up.

Sensing Static Pressure
For most industrial and scientific applications, the only air measurements needed are those of static pressure, total pressure and temperature. With these, air velocity and volume can be quickly calculated.

To sense static pressure, five types of devices are commonly used. These are connected with tubing to a pressure indicating instrument. Fig. 1-A shows a simple thru-wall static pressure tap. This is a sharp, burr free opening through a duct wall provided with a tubing connection of some sort on the outside. The axis of the tap or opening must be perpendicular to the direction of flow. This type of tap or sensor is used where air flow is relatively slow, smooth and without turbulence. If turbulence exists, impingement, aspiration or unequaled distribution of moving air at the opening can reduce the accuracy of readings significantly.

Fig. 1-B shows the Dwyer No. A-308 Static Pressure Fitting. Designed for simplified installation, it is easy to install, inexpensive, and provides accurate static pressure sensing in smooth air at velocities up to 1500 FPM.

Fig. 1-C shows a simple tube through the wall. Limitations of this type are similar to wall type 1-A.

Fig. 1-D shows a static pressure tip which is ideal for applications such as sensing the static pressure drip across industrial air filters and refrigerant coils. Here the probability of air turbulence requires that the pressure sensing openings be located away from the duct walls to minimize impingement and aspiration and thus insure accurate readings. For a permanent installation of this type, the Dwyer No. A-301 or A-302 Static Pressure Tip is used. It senses static pressure through radially-drilled holes near the tip and can be used in air flow velocities up to 12,000 FPM.

Fig. 1-E shows a Dwyer No. A-305 low resistance Static Pressure Tip. It is designed for use in dust-laden air and for rapid response applications. It is recommended where a very low actuation pressure is required for a pressure switch or indicating gage – or where response time is critical.

Measuring Total Pressure and Velocity Pressure
In sensing static pressure we make every effort to eliminate the effect of air movement. To determine velocity pressure, it is necessary to determine these effects fully and accurately. This is usually done with an impact tube which faces directly into the air stream. This type of sensor is frequently called a “total pressure pick-up” since it receives the effects of both static pressure and velocity pressure.

In Fig. 2, note that separate static connections (A) and total pressure connections (B) can be connected simultaneously across a manometer (C). Since the static pressure is applied to both sides of the manometer, its effect is canceled out and the manometer indicates only the velocity pressure.

To translate velocity pressure into actual velocity requires either mathematical calculation, reference to charts or curves, or prior calibration of the manometer to directly show velocity. In practice this type of measurement is usually made with a Pitot tube which incorporates both static and total pressure sensors in a single unit.

Essentially, a Pitot tube consists of an impact tube (which receives total pressure input) fastened concentrically inside a second tube of slightly larger diameter which receives static pressure input from radial sensing holes around the tip. The air space between inner and outer tubes permits transfer of pressure from the sensing holes to the static pressure connection at the opposite end of the Pitot tube and then, through connecting tubing, to the low or negative pressure side of a manometer. When the total pressure tube is connected to the high pressure side of the manometer, velocity pressure is indicated directly. See Fig. 3.

Since the Pitot tube is a primary standard device used to calibrate all other air velocity measuring devices, it is important that great care be taken in its design and fabrication. In modern Pitot tubes, proper nose or tip design – along with sufficient distance between nose, static pressure taps and stem – will minimize turbulence and interference. This allows use without correction or calibration factors. All Dwyer Pitot tubes are built to AMCA and ASHRAE standards and have unity calibration factors to assure accuracy.

To insure accurate velocity pressure readings, the Pitot tube tip must be pointed directly into (parallel with) the air stream. As the Pitot tube tip is parallel with the static pressure outlet tube, the latter can be used as a pointer to align the tip properly. When the Pitot tube is correctly aligned, the pressure indication will be maximum.

Because accurate readings cannot be taken in a turbulent air stream, the Pitot tube should be inserted at least 8-1/2 duct diameters downstream from elbows, bends or other obstructions which cause turbulence. To insure the most precise measurements, straightening vanes should be located 5 duct diameters upstream from the Pitot tube.

How to Take Traverse Readings
In practical situations, the velocity of the air stream is not uniform across the cross section of a duct. Friction slows the air moving close to the walls, so the velocity is greater in the center of the duct.

To obtain the average total velocity in ducts of 4″ diameter or larger, a series of velocity pressure readings must be taken at points of equal area. A formal pattern of sensing points across the duct cross section is recommended. These are known as traverse readings. Fig. 4 shows recommended Pitot tube locations for traversing round and rectangular ducts.

In round ducts, velocity pressure readings should be taken at centers of equal concentric areas. At least 20 readings should be taken along two diameters. In rectangular ducts, a minimum of 16 and a maximum of 64 readings are taken at centers of equal rectangular areas. Actual velocities for each area are calculated from individual velocity pressure readings. This allow the readings and velocities to be inspected for errors or inconsistencies. The velocities are then averaged.

By taking Pitot tube readings with extreme care, air velocity can be determined within an accuracy of ±2%. For maximum accuracy, the following precautions should be observed:

  1. Duct diameter should be at least 30 times the diameter of the Pitot tube.
  2. Located the Pitot tube section providing 8-1/2 or more duct diameters upstream and 1-1/2 or more diameters down stream of Pitot tube free of elbows, size changes or obstructions.
  3. Provide an egg-crate type of flow straightener 5 duct diameters upstream of Pitot tube.
  4. Make a complete, accurate traverse.

In small ducts or where traverse operations are otherwise impossible, an accuracy of ±5% can frequently be achieved by placing Pitot tube in center of duct. Determine velocity from the reading, then multiply by 0.9 for an approximate average.

Calculating Air Velocity from Velocity Pressure
Manometers for use with a Pitot tube are offered in a choice of two scale types. Some are made specifically for air velocity measurement and are calibrated directly in feet per minute. They are correct for standard air conditions, i.e., air density of .075 lbs. per cubic foot which corresponds to dry air at 70°F, barometric pressure of 29.92 inches Hg. To correct the velocity reading for other than standard air conditions, the actual air density must be known. It may be calculated if relative humidity, temperature and barometric pressure are known.

Most manometer scales are calibrated in inches of water. Using readings from such an instrument, the air velocity may be calculated using the basic formula:

With dry air at 29.9 inches mercury, air velocity can be read directly from the Air Velocity Flow Charts. For partially or fully saturated air a further correction is required. To save time when converting velocity pressure into air velocity, the Dwyer Air Velocity Calculator may be used. A simple slide rule, it provides for all the factors needed to calculate air velocity quickly and accurately. It is included as an accessory with each Dwyer Pitot tube.

To use the Dwyer Calculator:

  1. Set relative humidity on scale provided. On scale opposite known dry bulb temperature, read correction factor.
  2. Set temperature under barometric pressure scale. Read density of air over correction factor established in #1.
  3. On the other side of calculator, set air density reading just obtained on the scale provided.
  4. Under Pitot tube reading (velocity pressure, inches of water) read air velocity, feet per minute.

Determining Volume Flow
Once the average air velocity is know, the air flow rate in cubic feet per minute is easily computed using the formula:

Q = AV
Where: Q = Quantity of flow in cubic feet per minute.
A = Cross sectional area of duct in square feet.
V = Average velocity in feet per minute.

Determining Air Volume by Calibrated Resistance
Manufacturers of air filters, cooling and condenser coils and similar equipment often publish data from which approximate air flow can be determined. It is characteristic of such equipment to cause a pressure drop which varies proportionately to the square of the flow rate. Fig. 5 shows a typical filter and a curve for air flow versus resistance. Since it is plotted on logarithmic paper, it appears as a straight line. On this curve, a clean filter which causes a pressure drop of .50″ w.c. would indicate a flow of 2,000 CFM.

For example, assuming manufacturer’s specification for a filter, coil, etc.:


Other Devices for Measuring Air Velocity
A wide variety of devices are commercially available for measuring air velocities. These include hot wire anemometers for low air velocities, rotating and swinging vane anemometers and variable area flowmeters.

The Dwyer No. 460 Air Meter is one of the most popular and economical variable area flowmeter type anemometers. Quick and easy to use, it is a portable instrument calibrated to provide a direct reading of air velocity. A second scale is provided on the other side of the meter to read static pressure in inches w.c. The 460 Air Meter is widely used to determine air velocity and flow in ducts, and from supply and return grilles and diffusers. Two scale ranges are provided (high and low) with calibrations in both FPM and inches w.c.

To Check Accuracy
Use only devices of certified accuracy. All anemometers and to a lesser extent portable manometers should be checked regularly against a primary standard such as a hook gage or high quality micromanometer. If in doubt return your Dwyer instrument to the factory for a complete calibration check.


The bigest VRF System made in Brazil at RB1 commercial building located in Rio de Janeiro. You can read the news history at the Magazine page 24. To read the news clique here!



The HVAC Company MSTC Mechanical was showed as success case at Clima Brazil Magazine. Read the Magazine: Clique here!

The connected home subset of the Internet of Things (IoT) is poised for explosive growth. This is a natural fit for HVAC contractors.


What is the Connected Home?
The connected home is an eco-system of devices, services, and apps in a residential building that are networked together to enhance the homeowner experience.  This includes devices as simple as a sensor that notifies the homeowner when it’s opened.  For example, a homeowner might have one of these sensors attached to a gun safe or a liquor cabinet.

Devices can also be more sophisticated such as high definition cameras that respond to certain types of movement in certain zones, video doorbells, thermostats, flood alarms, and so on.  Devices can respond based on a variety of conditions, including the proximity of occupants based on their mobile phones (i.e., geofencing).

Why HVAC Trumps Everyone Else
Today, connected home products are either DIY or installed by cable and home security companies. DIY is not a popular option for the vast majority of consumers, who struggle to get their Outlook calendars to sync with their Android phones and who need different remotes for their TV, cable box, and Blue Ray players.  People do not want multiple hubs and apps for an array of products that do not work together.  They want someone to make everything work for them.

Cable and security companies can integrate parts of the connected home, but they cannot offer end-to end solutions. They are not qualified to touch the HVAC. In fact, they are afraid of it.

For HVAC, it’s more than the ubiquity of the service and installation work contractors can offer, it’s the existing relationships.  The current connected home turnkey offerings sold by cable and security companies involve heavy marketing and door-to-door canvasing to people who lack a relationship with them.  Contractors can market and sell to people where there is an existing relationship and degree of trust.  If a security company can successfully offer connected home solutions by sending pure salespeople door-to-door, how much more successful can a contractor be, offering options through technicians, already at the home solving problems.

What’s In It For Contractors?

Connected home solutions offer significant revenue opportunities through cloud (WiFi) or cellular data services.  The connected home doesn’t work without the ability to store video and connect with mobile phones, tablets, and/or computers.  Without the cloud or cellular connectivity, a homeowner may be able to see who is at the door from a phone while at home, but not while away, which is uninteresting to most people.  The data service necessitates a monthly charge.

Because they bundle financing for installed equipment with the data services, cable and security companies charge as much as $70 per month. Contractors can give people the option to finance installed connected home equipment or pay for it outright, while separating the data service. The cost of the data service under this approach can range from $20 to $30 per month or be combined with an HVAC service agreement for more.

1000 connected home service agreements X  $20 gross profit per month per agreement X 12 months = $240,000 gross profit

That is $240,000 free and clear of the maintenance portion of a service agreement for every thousand agreements put in place.  While there is some additional overhead that will be needed, almost all of this will fall to the bottom line.  Moreover, this will add around $1 million to the value of the business!  Add a thousand connected home customers and add a million dollars to the exit strategy.

Selling a thousand connected home data plans is far easier than selling maintenance agreements.  Maintenance agreements are like trips to the dentist.  You go because you need to and you know it will eventually get painful if you skip it.  Yet, contractors successfully sell them. The connected home agreements are easier sales because people want them.

A home’s connected home network is not static.  It can grow every year, giving contractors an ability to go back to the well again and again, offering other devices and expanded data services.

When bundled with equipment as an option, the connected home offering can make a contractor stand out from the competition, giving his company an edge in desirability.  As a standalone offering, connected home products carry demand independent of the weather, giving contractors another off-season sales opportunity.

Hurdles Contractors Face
Before contractors can offer connected home solutions, they must overcome a number of hurdles.  First, they need to choose the products they will offer.  This is the very thing that’s stymied so many consumers.  It is the job of the contractor to select products that will make up the eco-system he will offer, to ensure everything communicates, to know what will not work with it, and to communicate this with consumers.  This will take research and experimentation.

Contractors need a partner who can provide cloud based data services and/or cellular services, which can then be resold.  This is another research effort and an important one because the recurring monthly revenue is the real prize.

Contractors should decide if they want to engage in home security, or not.  Offering security services requires licensing and other hurdles, which vary state-by-state.  The contractor can partner with a security company, but the security company with want the recurring monthly revenue.  Alternatively, the contractor can take a home awareness approach, where there is no third party monitoring.  Alerts are sent to the homeowner’s phone or other devices and the homeowner decides how to respond.  The latter approach can save consumers considerable money.  If sirens and cameras are in place, consumers may feel comfortable skipping third party monitoring (and fines from the police department for false alarms).

Finally, contractors must decide how to package and market their offering.  Do they want to charge normal margins for installed connected home products or cut the margins for greater adoption and more recurring monthly revenue streams?

If these and other hurdles can be cleared, a connected home offering can transform a contracting business into a highly profitable, highly saleable, money machine.



LG Electronics USA is helping to provide sustainability efforts for the new Growing Green Center on the campus of the Parks & People Foundation. The organization is a nonprofit that hosts out-of-school time education and recreation youth programming while also supporting, renovating, and creating new park and green spaces throughout Baltimore.

The newly dedicated Jean and Sidney Silber Center supports Parks & People’s mission to unite Baltimore through parks. The LG-sponsored center — located steps from the Parks & People’s LEED Platinum headquarters in Baltimore’s Druid Hill Park — will serve as the new home for Branches, Parks & People’s high school environmental internship program that employs interns in maintaining public green spaces while earning a paycheck and learning about educational and green-career pathways after high school.


“LG’s energy-efficient solutions for commercial and residential facilities help create a more sustainable future, and we’re proud to contribute to the community through this process,” said Kevin McNamara, senior vice president and general manager of air conditioning technologies at LG Electronics USA. “Our support for the new Silber Center underscores LG’s mission to give back to local communities with a focus on innovative, greener systems.”

Parks & People Foundation President & CEO Lisa Millspaugh Schroeder thanked LG and other project partners for making the newest addition to its campus a success.

“The new Jean and Sidney Silber Center showcases the highest level of green building design, and we can’t wait for campus guests to get a closer look,” she said.

The Silber Center features a number of energy efficient and Energy Star® certified LG products, including air conditioning systems, consumer electronics, and home appliances. One such system is the LG Multi V Mini single-phase air conditioning system which offers LG’s flagship VRF technology to cool or heat an entire building or just a single area or room.

The Silber Center debuted at the Greenbuild Expo sustainable building conference in Washington 18 months ago. It was unveiled in its permanent location with a tour highlighting the importance of incorporating sustainable materials in building and education.