Proactive Design: Humidity Control part 2

When we refer to “Proactive Design,” we’re talking about elements of maintenance and design that work to either prevent problems before they begin, or to identify and solve small problems early, before they escalate into bigger—aka more inconvenient and expensive—problems. In part 1, we discussed how proactive plumbing design, construction, and maintenance are key in stopping water or moisture damage before it begins. In part 2, we’ll discuss how controlling indoor humidity is just as important in preventing mold, damage, and health issues linked to excess moisture.

Recap: Why is moisture control important?

To recap: according to a 2004 study by the Institute of Medicine of the National Academy of Sciences commissioned by the US Centers for Disease Control, there is a demonstrated or suggested association between exposure to “damp” indoor environments and adverse health effects such as:

  • Upper respiratory symptoms
  • Cough
  • Wheeze
  • Asthma symptoms or development
  • Increased fungal and infection issues in “immunocompromised” residents.

From a structural perspective, moisture damage to buildings and their components can be significant as well, such as:

  • Corroded wire and other metal components
  • Mold and bacteria growth
  • Attraction of insect pests
  • Deterioration of the building itself; particularly flooring, drywall, framing, and foundations

What can be done about it?


Quality Materials and Workmanship

Just as with plumbing, the Uniform Construction Code (UCC) contains specific guidelines for Heating and Cooling equipment as well as ventilation and fresh air requirements. According to the EPA, the most common sources of indoor moisture problems are issues with the building envelope’s integrity. Properly sized and sealed ductwork and venting installed to code go a long way towards managing indoor air quality.


One way to achieve direct, specific control over humidity levels is to equip the HVAC system with a dehumidifier. While portable dehumidifiers can be a helpful temporary solution and an air conditioning system will remove some humidity as part of the cooling process, adding a dedicated dehumidification unit lets the occupant precisely control humidity levels throughout the entire structure. This can be essential in industrial or healthcare applications, where precise relative humidity is necessary to manufacturing, equipment manufacturing, or patient care. Plus, a dehumidifier will take some of the load off the AC system, helping it to run more efficiently and prevent overcooling during high-humidity weather. In addition, we feel more comfortable when indoor humidity is between 30-50%, which can allow the AC to be set a few degrees higher without losing comfort. This can offer significant savings on cooling costs.

Louvers, Flashing, & Curb Adapters

No, they aren’t just for looks, though that doesn’t hurt. Quality louvers, flashing, and curb adapters can offer protection from rain or groundwater runoff while still allowing proper airflow.

Equipment Sizing

Proper sizing and selection of HVAC equipment is key to controlling humidity levels. Your JK HVAC estimator takes a number is elements into consideration when designing a heating and cooling system, including but not limited to the footprint of the building, ductwork tightness and location (relative to insulated space), glass amounts and positions (windows and doors), solar orientation, occupancy, climate, and the specified building envelope conditions.

For optimum comfort and humidity control, an air conditioner needs long runtimes. An oversized system will frequently cycle on and off (at about ten minutes or less); in addition to putting unwanted wear and tear on your unit, this prevents the unit from working long enough to provide effective dehumidification. At the opposite end of the spectrum, an undersized AC will run continuously but inconsistently and ineffectively, leaving you with insufficient or uneven cooling and humidity.


An ERV, or “Energy Recovery Ventilator,” recovers energy from the airstream discharged from the building and transfers this energy to the incoming air used for ventilation. In other words, an ERV can provide the benefits of fresh air while still offering filtration and control. The 2015 IRC/IECC requires a continuously operating mechanical ventilation system to remove stale air and add fresh air to each dwelling. This is a new requirement that was not included in the prior version of the PA UCC. As a bonus, ERVs are also an efficient way to manage humidity year-round. In the summer cooling season, an ERV removes the humidity from the incoming outdoor air and adds it to the exhaust air, keeping it out of the building. In the winter, the opposite is performed. The moisture always moves from the air stream with higher humidity to the lower, thus balancing your indoor relatively humidity all year long.


At JK Mechanical, we understand that there are hundreds if not thousands of decisions that go into construction and design. Top quality products and materials ensure reliability and energy efficiency, and our attention to detail optimizes overall performance, aesthetics, and ease of management.  Let us work with you, and we’ll provide a smooth process with outstanding results. Talk to our estimating team to learn more about humidity control and how we can help with HVAC and Plumbing from design and construction through maintenance and service for years to come.



Comments are closed.