Common HVAC Issues Can Be Fixed During a Building Renovation

HVAC installations represent a large share of energy consumption in buildings. In commercial and institutional applications, heating and cooling equipment may account for over 50 percent of energy expenses. Processing equipment often has a higher consumption in industrial settings, but HVAC systems are still among the largest loads.

An HVAC upgrade is disruptive for a building in operation, since it can leave occupants without heating and cooling temporarily. The upgrade project also causes noise and discomfort with the potential to affect productivity. However, a major building renovation provides an excellent chance to fix HVAC issues because the entire property will be modified anyway.

Consider the following common HVAC issues that can be fixed more easily as part of a building renovation:

Replacing Oversized HVAC Equipment

Construction codes have changed over time and this includes the sizing procedure for HVAC equipment. Many old properties have oversized heating and cooling systems, and this has two negative consequences:

  • Excessive energy consumption.
  • Excessive heating or cooling, which may cause discomfort and health issues.

HVAC engineers do not recommend purchasing equipment based on “rules of thumb” because this practice often leads to oversizing. The capacities should be calculated according to local building codes, which are based on design standards from ASHRAE and other industry authorities.

If oversized HVAC units are also old, low energy efficiency can be expected. Newer units with an optimal capacity and a higher efficiency can achieve significant energy savings.

Fixing Air Leaks in Buildings

Air leaks are detrimental for the performance of HVAC systems because they cause unwanted heat gain and heat loss. Even the most efficient heating and cooling equipment will waste energy in a building with air leakage issues. Air leaks may also occur internally between conditioned and unconditioned spaces and they also affect HVAC efficiency in this case.

Because air leaks produce no visual signs, they must be detected with methods like thermal imaging and pressurization tests. A major renovation provides an excellent change to inspect the building envelope to find these and other issues.

Reducing Noise and Vibration in HVAC Equipment

Old HVAC units often produce plenty of noise and vibration, especially if their maintenance has been deficient. Equipment supports wear down over time, losing their capacity to isolate vibration. Also consider that old installations are often oversized, which worsens the issue.

Noise and vibration can be minimized with a smart building layout, placing HVAC equipment away from sensitive areas. An adequate selection of equipment supports also minimizes the vibration transferred from HVAC units to other building elements.

The Importance of Adequate HVAC Controls

The thermostats in old HVAC systems are often set at extreme temperature values: the lowest temperature in the scale is used in summer and the highest is used in winter. However, this wastes energy in the form of excessive heating and cooling. Even the most efficient equipment consumes more energy than necessary if the thermostat is not set properly.

The U.S. Department of Energy recommends setting back the thermostat to save energy. For every 1 degree F of setback, energy consumption can be reduced by up to 3 percent. A smart thermostat can accomplish this automatically for small HVAC equipment, and a building automation system (BAS) can be used for larger units like chillers and boilers.

About the Author

Michael Tobias, P.E., LEED AP, CEM
Michael Tobias is the founder and principal of Chicago Engineers, an Inc. 5000 Fastest Growing Company in America. He leads a team of 30-plus mechanical, electrical, plumbing, and fire protection engineers from the company headquarters in New York City. He has led more than 1,000 projects in Chicago, New York, New Jersey, Pennsylvania, Connecticut, Florida, Maryland and California, as well as Singapore and Malaysia.

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