Posts tagged ‘indoor air quality’

April 5, 2017, 9:00 am

Specifying With Thermal Comfort in Mind


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March 21, 2017, 9:00 am

How VRF Addresses Educational Facilities’ IAQ Challenges


As VRF has continued to innovate and improve, it has evolved from being a good solution for educational facilities to the solution. Read more in our K-12 Educational Facilities White Paper.

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March 9, 2017, 9:00 am

Project Profile: The Covenant School


The Covenant School was founded 30 years ago in Charlottesville, Virginia. The lower school, for students in pre-K through 6th grade, is located in a 65,000-square-foot historic brick building dating back to 1935. With almost 300 students, faculty and staff members, the school needs to operate seamlessly so when the old boiler system started to fail, it needed to find a new heating system as soon as possible. The Covenant School selected our Variable Refrigerant Flow (VRF) technology to answer that need, providing zone control, air filtration and the added bonus of cooling.

To find a suitable system, the school called in Jay Taggart, school board member and the President of W.E. Brown, Charlottesville – the project’s installing contractor. Taggart compared two systems – a water-based chiller and VRF – and made a recommendation to the school. He said, “Everyone agreed that ductwork couldn’t happen, and we were worried the roof couldn’t handle the weight of a chiller, so we came in with a CITY MULTI® solution. With CITY MULTI, there wouldn’t be nearly as much equipment on the roof as a water-based solution, making VRF significantly lighter. Also, CITY MULTI offered simultaneous heating and cooling in a real way because of the heat recovery, and a more detailed level of zoning. And because refrigerant piping is smaller than water piping, VRF offered a more compact solution.”

Installation proceeded during the summer while the students were away, ensuring an easy process for the project team and school. Since the completion of the project, the school has seen improvement in comfort and health. Taggart said, “This is the first time the building has ever been fully air conditioned or had air filtration, so the air quality has gone up drastically. Many teachers say they’ve noticed an impact on their health: fewer allergies and colds.”

Between the improved indoor air quality and increase in control, The Covenant School can now offer a comfortable learning environment for its students and teachers year-round. To read more about The Covenant School, check out the case study here.

Written by MitsubishiHVAC
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July 27, 2016, 9:00 am

Project Profile: Simpson Hall – University of Florida


For University of Florida alumni and residents, the city of Gainesville is affectionately referred to as “The Swamp.” It was exactly that muggy humidity and those high temperatures that plagued the school’s buildings, prompting renovations to the electrical and HVAC systems in Simpson Hall. Last renovated in the mid 1970s, the 34,847-square-foot residence hall was in dire need of an HVAC update.

Chad Doering, mechanical engineer and project manager, Moses & Associates, Inc., Gainesville, specified the new HVAC system. “We wanted to be able to dehumidify and maintain indoor pressure, which was not something we were able to do well with the previous system.” He recognized that a Variable Refrigerant Flow (VRF) system would not only achieve these goals, but would do so cost-effectively – both in terms of the lifecycle-cost analysis he completed, and with the money saved by installing less equipment. Doering said, “This install covers 143 zones and if we wanted to give each student personalized control, we would have needed a branch controller for each zone – that’s 143 branch boxes. With Mitsubishi Electric, we only needed 15 boxes – and five of those were for the outdoor units.”

Our VRF systems are not just more efficient than the competition’s, they are incomparably more energy-efficient than conventional units. The chart below demonstrates the energy savings at Simpson Hall compared to North Hall – a comparable residence hall renovation the school completed around the same time, but with a chilled-water system:


The success of the Simpson Hall renovation prompted the school’s housing department to select our products for a second project – Cypress Hall. Despite being one of the largest residence hall construction projects on campus, the HVAC installation at Cypress Hall cost just $26 per square foot – beating Simpson Hall’s installation costs by an average of $4.

To learn more about how Simpson Hall compares to the installations in North Hall and Cypress Hall, check out the case study.

April 26, 2016, 9:00 am

Projects From Our Colleagues: Morgan & Associates, Kansas City

Our colleagues in Kansas City, Kansas, Morgan & Associates, Inc., have been doing some meaningful work specifying our Variable Refrigerant Flow (VRF) products. Recently, they helped the Mercy & Truth Medical Clinic – a faith-based, childbirth facility – renovate its building, which re-opened last month. The alliance between the Mercy & Truth Medical Mission and the New Birth Company is working to help fight the high infant mortality rate impacting Wyandotte County, Kansas. We’re proud that Morgan & Associates are a part of this initiative.

As can be expected, birthing facilities demand a specific environment to help keep mothers and their newborns healthy, safe and comfortable. Bringing adequate air flow into the birthing rooms meant maneuvering through three rooms on the first floor of the renovated brick building. Morgan & Associates recognized that recommending and installing VRF would provide maximum flexibility between the offices, exam rooms and birthing suites – each having its own comfort needs.

For the birthing suites and nursing station, Mercy & Truth selected our CITY MULTI® VRF technology with heat recovery, while the remaining office space runs on our standard VRF heat pumps. Morgan Knipp, president of Morgan & Associates, said, “Being able to contribute our expertise in the HVAC area to help counteract this frightening infant mortality rate serves such a higher purpose. We are eager to see that statistic change and the lives transformed from this place.”

January 8, 2016, 9:00 am

Project Profile: Garland DOE Zero Energy Ready Home

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Wade Griffith Photography


For homebuilder Steve Brown, working around the renovation constraints of a 51-year-old home in Garland, Texas, proved as overwhelming as some good ol’ Texas heat. Nevertheless, Brown pushed that challenge further – seeking to create a home so energy-efficient that a renewable energy system could offset all or most of its annual energy consumption. What resulted was the country’s first “deep rehab” home to earn certification from the U.S. Department of Energy’s Zero Energy Ready Home (ZERH) program. We’re excited to say that our technology helped make it possible.

Brown described the layout of the house as “static” and “closed-off.” Since natural airflow was stifled, in-home comfort was entirely left to the HVAC system. Brown said, “Mitsubishi [Electric] is whisper-quiet and it has a good circulation pattern. We’re getting a throw of 20 feet.” The fact that our system was “whisper-quiet” was a particularly important factor. Brown said, “We’d used Daikin before but the blowers are a little loud.”

The final product in Garland is unmatched. While neighbors have paid upward of $400 per month for electricity, homeowner Bonnie Sanchez has spent an average of $102 – and as low as $37. We’re thrilled (but of course not surprised) to see such savings, and honored that our technology was selected to show what the ZERH program can accomplish.

Read the full case study for more details.

December 21, 2015, 11:32 am

Project Profile: Jesuit Spirituality Center at Saint Charles College


dec22Most retrofits are challenged by the difficulty of replacing old, cumbersome ductwork, but imagine retrofitting a building designed before air conditioning! That was the challenge in Grand Coteau, Louisiana, where Reverend James P. Bradley, S.J., wanted to update the HVAC system at the Jesuit Spirituality Center at Saint Charles College. The solution to that challenge: our VRF technology.

The century-old building houses a novitiate (Jesuit training center), a spirituality center for retreats and a 22-bed assisted living facility. For such a large, diverse project, Larry Blanchette, the project’s engineer, elected to use our VRF technology for a number of reasons:

  1. Cost Efficiency – Compared to the chilled water and hot water system that Blanchette initially planned to incorporate, VRF simply priced out better.
  2. Spacing – In a building that covers the equivalent of a city block, there were a number of large beams hidden in the structure. The building’s size and layout presented a challenge that VRF’s compact design was able to help navigate.
  3. Mold – With high humidity and 22 elderly residents, mold was a constant threat. VRF offered personalized comfort and better indoor air quality. “A couple men had asthma and allergy problems, but they’ve gone away,” said Bradley.

Above all, a central controls system has made managing the facility not only convenient, but has also kept the project under the expected cost.
Read the full case study for more details.

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October 9, 2014, 3:52 pm

ASHRAE and IAQA Join Forces

ASHRAE-logoOctober 9_ASHRAE and IAQA merge_Image2

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and the Indoor Air Quality Association, Inc. (IAQA) announced on July 14 that they are combining forces. IAQA, the nation’s largest indoor air quality trade association, is now part of the prominent industry organization. The groups will work together to improve indoor air quality in the building environment.

The collaboration is expected to result in stronger programming and services. Indoor air quality technical guidance and educational programs for industry members should benefit, as well. The most significant result, as suggested by ASHRAE President Tom Phoenix, is “improved indoor air quality for the world around us.”

Click here to learn more about the merger.

Written by MitsubishiHVAC
February 18, 2014, 4:59 pm

Is Duct Leakage Testing Really Just Smoke & Mirrors?

February 18_Duct Leakage Testing ImageOf the more than a million miles of duct work in U.S. homes, industry experts estimate that more than two-thirds of them have leaks. This can account for as much as 25 percent of a home’s total energy loss. Duct leakage can dramatically reduce the HVAC equipment’s capacity and performance, causing hot and cold spots and humidity problems. Leaky ducts can also significantly increase homeowners’ utility bills and, worse yet, create air quality problems by pulling pollutants and other health hazards directly into the home. All of this creates an uncomfortable living environment for homeowners and their families.

Keeping in mind the number of issues that can arise from leaky ducts, ACH&R News writer David Richardson investigates the current metrics used for residential duct leakage testing, a verification process put in place by the International Energy Conservation Code (IECC) to ensure that healthy, clean air is provided to homeowners. In his article, “Using Duct Surface for Leakage Testing?” Richardson informs us of his findings:

Current duct leakage testing involves pressurizing the duct system to the standard 25 pascals using a calibrated fan and comparing the airflow against the conditioned floor area (CFA) of a home. Depending on local codes, the total leakage allowed is limited anywhere from 12 cubic feet per minute (cfm) per 100 square feet of CFA to 4 cfm, per the 2009 and 2012 IECC codes, respectively.

The problem with these measurements comes two fold. First, as Richardson explains, duct leakage occurs at the surface area of the duct, not the CFA. Therefore the current formula for testing duct leakage does not test the actual area of concern. Secondly, the 25 pascals value that the industry has deemed the standard operating pressure is simply outdated. Richardson writes that you rarely find duct systems running at that pressure in the field nowadays and in fact, pressures are usually elevated due to undersized duct systems.

No matter which way you cut it, Richardson’s examination shows that residential duct leakage testing can easily yield misleading or inaccurate results. So, as he asks, do we revise a formula that has been used for years or do we sacrifice some level of accuracy for convenience and simplicity?

What’s our answer? Go duct-free. Visit to learn more on how you can avoid the smoke and mirrors of duct leakage testing by choosing ductless technology as the HVAC solution.

November 12, 2013, 4:14 pm

Ductless on Every Job: Hot and Cold Spots

November 12_Ductless on Every Job - Hot and Cold Spots Image

Our Ductless on Every Job campaign is in full swing, so we’re back to educate contractors on yet another solution where they could consider ductless as an answer to a sales call’s need. This week, we’re focusing on how ductless can solve the hot and cold spots dilemma.

Even with the doors and windows closed, the homeowners still feel drafts inside. They’re comfortable in one room, too hot in another and cold everywhere else in the house. Sound familiar? If your customer is describing these common annoyances, rest assured that although the cause of hot and cold spots may be difficult to identify, there is one easy and effective solution – installing a ductless system.

Uneven temperatures in a house mean one thing: the home’s HVAC system is not working properly. If left unaddressed, energy will undoubtedly be wasted and homeowners will end up spending way more than they should on their utility bills. So, to help your customers win the battle for comfort, here are the common sources of hot and cold spots and how to explain to homeowners that ductless technology can rid the home of them:

  • The HVAC system isn’t properly sized. Systems that are too small cannot provide sufficient amount of air to heat and cool the entire home, and bigger is not always better when it comes to an HVAC system. Short-cycling, shortened lifespan and higher energy and operational costs are all results of inappropriately sized systems. With Mitsubishi Electric’s ductless systems, however, homeowners don’t have to worry about running into these issues. We offer a wide range of capacities to match the specific room size and requirements of the home. With our advanced zoning technology, multiple indoor units can be installed and individually controlled, allowing homeowners to condition only the occupied spaces and not waste energy conditioning the vacant areas. Whereas traditional HVAC systems only operate at either zero percent or 100 percent, our ductless systems use INVERTER-driven compressors that ramp up quickly to provide the energy necessary to achieve the heating or cooling demand then varies its speed to maintain the desired comfort level. The i-see™ Sensor found on some indoor units scans the room’s ambient temperature readings, detects any disparities and then adjusts the airflow to provide uniform comfort throughout the room. With these advanced technologies, the HVAC system performs only at the minimum energy levels necessary. Because of this, energy is not wasted when partial-load conditions are present, which is occurs about 97 percent of the time.
  • Leaking or poorly insulated ducts. Research from the U.S. Department of Energy discovered that about 30 to 40 percent of the air traveling through ducts leaks, which negatively impacts both the system’s efficiency and the air quality it provides. Not to mention, holes in the ducts introduce dust, bugs, allergens and other particles so what should be clean, filtered air ends up dirty and unhealthy.
  • Obstructed air vents. Floor or wall air vents blocked by decorations and furniture could also cause temperature swings in a home. Our expansive offering of indoor unit styles and combinations provide the ultimate design flexibility. The system’s components are compact, lightweight and can be installed in small areas, providing more space for interior design by minimizing the unit’s visual and auditory impact. Wall-mounted, ceiling-recessed, horizontal-ducted and floor-mounted indoor unit installation options allow the homeowner to design their space how they want to and not how they have to.

It is no doubt that hot and cold spots are uncomfortable to live with and that is the opposite of what homeowners should feel when they’re in their home. Our ductless system is the one-stop-shop solution to eliminate uneven temperatures and provide the utmost, constant comfort.

To learn more about the benefits of ductless systems, visit or go to

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