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Questions from our Customers:

The questions below represent a brief overview of some of the questions our team experiences on a continuous basis. For more specific questions or more comprehensive answers, please contact us for a consultation.

Why should I have an engineer design the HVAC system for my existing building?

Every building and application is different and has different requirements. A one size fits all solution is typically not the best one especially in high humidity climate zones such as the South Eastern United States. Without doing an accurate heat load of the building, the equipment selected may be over or undersized which may lead to potential humidity and temperature issues. Additionally, an engineered design takes into consideration:

  • The optimal air distribution in the building though a designed ductwork layout.
  • The most suitable equipment required based on internal and external latent and sensible loads of the space.
  • Ideal outside air volumes determined through testing to ensure desired pressures within the space to prevent infiltration.

Why should independent Testing, Adjusting and Balancing be performed on a new or existing system?

TAB should be performed on a new or existing system in order to ensure that the airflow in each space and the airflow provided by each piece of equipment is as per design. Several issues including humidity problems, capacity problems and ventilation problems may result due to improper initial balancing. TAB of a building is a good step to eliminate potential air conditioning problems from occurring in the future.

What is Total Building Commissioning? Why is it important?

Total Building Commissioning is simply ensuring that the new building operates as the owner intended and as per the designs. It is important to make sure that a quality project is delivered to the end user and that all aspects of the project are addressed completely.

What is Variable Refrigerant Flow (VRF)? What are the advantages and commercial applications of VRF Technology over standard Commercial Equipment?

Variable Refrigerant Flow technology involves varying the amount of refrigerant to indoor units based on each indoor unit’s demand. The two common types of systems utilizing VRF technology are Heat Recovery Systems and Heat Pump Systems. Heat Recovery Systems are typically more complicated and can allow for some indoor units in a system to be in cooling mode while some are in heating mode while maintaining a high level of efficiency. Heat Pump systems can provide either cooling or heating for all indoor units associated with a common outdoor unit.

VRF systems can provide significant advantages in the form of energy savings, space savings, project cost and maintenance. There are several commercial applications in which VRF systems are being implemented in lieu of traditional DX or Chilled Water Systems.

How do you know if your building is leaking too much air?

A Blower Door Test can be used to determine the leak rate. Different codes measure acceptable leak rates through different metrics including Total Leak Rate per Volume, Air Changes Per Hour and Leak Rate Per Envelope Area. However, as a rule of thumb, typically lower than 5% volume leak rate in a building is desired and indicates good construction. Higher leak rates indicate poor or loose construction.

How does a high leak rate affect a building? Why is lowering the leak rate of the building a priority?

Reducing the leak rate in a building through sealing and other means is a priority as there are several disadvantages to having a leaky building:

  • A leaky building requires more outside air to maintain a positive pressure. This increases tonnage required for cooling the outside air leading to significant added costs and energy usage.
  • A leaky building allows for more infiltration leading to humidity and temperature control issues and undesired condensation.

What is Blower Door Testing and Building Envelope Integrity testing?

Blower Door Testing and Building Envelope Integrity testing are both services provided by Matrix HVAC and involve determining the leak rate and identifying the sources of air leakage in a building.

  • Blower Door Testing involves installing a sealed door and a fan or a multiple fan setup to the building. All other intentional openings are closed and then the testing is performed. The test determines how much outside air needs to be introduced to the building to maintain the building at a certain positive pressure (typically 0.1” w.g.).
  • Building Envelope Integrity testing surveys the building to determine where the air is leaking out of the building. This information can then be used to potentially seal the building to reduce the leak rate. There are two main testing methods used: (1) Thermographic Imaging – An infrared thermal camera is used to pin point leaks. (2) Smoke Testing – A smoke puffer or smoke generator is used to identify building leaks.

What can cause humidity issues in a building? What are typical problems and potential solutions?

There are several factors which potentially could lead to high humidity in a building, especially in high humidity environments typical to the South East United states. A few are highlighted below:

  • Roof water leaks – water intruding through roof cracks or gaps is a significant factor leading to high humidity in buildings
  • Negative Building Pressure – Hot humid air may potentially infiltrate into the building leading to high humidity

There are a few ways to investigate and address humidity issues in a building depending on the root cause of the problems. A few services provided by Matrix to determine the cause of the issues are as follows:

  • Blower door testing – determines how leaky the building is.
  • Pressure mapping – creates a map of the pressures in a building relative to the outside.
  • Thermographic Imaging and Smoke Testing – Pin points leaks
  • Humidity and Temperature Logging – Measures real time the temperature and humidity in different locations to hone in on the problem areas.
  • Testing and Balancing – verifies correct equipment airflow volume and outside air.
  • Equipment Surveys – Ensures that the HVAC equipment is operating as required and determines if the current equipment is a root cause.

How does negative pressure in a building potentially lead to humidity and temperature control issues in the space?

Negative pressure in a building can be expressed as a building having a lower air pressure than the adjacent environment. When this is the case, air infiltration will occur. The volume of air entering the building will be dependent on how leaky the building is. If the ambient air has a high humidity, the air entering the building will transport moisture into the space from outside. This may potentially lead to humidity issues in the space. This is also true for temperature. Hot (or cold) air from outside might enter the building and induce heating or cooling loads into the space.

Positive pressure in a building is desired as the air brought into the building to achieve this is conditioned through the air handlers. Moisture removal occurs in the air handler itself rather than through undesirable condensation on surfaces potentially leading to mold and mildew. Typically, the outside air brought in through an HVAC system is included in the heat load and is accounted for.

How can kitchen hoods with exhaust be tackled to prevent negative pressure issues in the space?

Kitchen hoods may be a significant contributor to negative pressure in a building. Makeup from the hood itself and from outside air units must cover or exceed the volume exhausted by the hood in order to maintain a neutral or positive pressure in the space. This involves properly sizing the hood and hood makeup systems, designing and installing transfer grills if needed, and determining the right amount of total outside air introduced into the building.

What is NFPA 496 Code Compliance? Why is it important?

NFPA 496 is a code governing purge and pressurization for buildings and enclosures in hazardous classified environments. There are several requirements which must be followed and maintained in order to be Code Compliant.

What are the key differences between Mill/Industrial/Offshore duty equipment and typical Commercial equipment?

Matrix Severe Duty units for Mill/Industrial/Offshore applications are custom designed to meet the specific requirements for each application. Common differences between severe duty units and standard units are listed below:

Standard Commercial Units

  • Single Wall Painted Steel Construction
  • Belt Driven Standard Motor Evaporator Fan
  • Condenser fan with standard duty aluminum or steel fan blade
  • Coils with standard fins per inch

Severe Duty Units

  • Double Wall Stainless Steel Construction with Foam Injected Insulation
  • Low Leakage Panels and Doors
  • Stainless Steel Parts and Fittings for maximum Corrosion Resistance
  • Heavy duty Condenser Fan with TEFC Severe Duty Motors
  • Coated Coils for corrosion resistance

If you have a question not provided above, please feel to contact us at (985) 635-8309 or by email at sales@matrix-hvac.com.