We wanted to share a terrific article from the Journal of Light Construction titled, “Controlling Humidity in Warm Climates,” which featured many industry experts ecobeco’s President Brian Toll knows from his work on the ASHRAE 62.2 Indoor Air Quality in Residential Buildings standards committee.
This article tracks the difference between sensible heat (this is air temperature) and latent heat (this is air humidity), and its impact of temperature and humidity control. HVAC systems that are properly sized for a home should provide great cooling and dehumidification performance during peak load periods – when it is hot outside. However, in periods of partial loads (which is about 80% of the time in a typical house), we often find that the system does not dehumidify well until we push the thermostat down to unbearably cold temperatures. Why? Because most HVAC systems focus primarily on sensible heat, not latent heat. A dedicated dehumidifier focuses on latent heat.
The problem gets worse as homes become more energy efficient (NOTE – Maryland’s new construction code is among the most efficient in the United States) because the home operates on partial loads almost all of the time. This article describes how newer homes need three systems – a cooling system, a dehumidification system, and a fresh air system (for indoor air quality). For winter, you need three as well – a heating system, a humidification system, and a fresh air system.
Some manufacturers sell all three systems based on a centrally ducted system. Other manufacturers sell systems that are installed room by room (or sets of rooms). There are many permutations, and it’s important to find an HVAC contractor who will model the performance of your home and design a solution that incorporates all 3 components. This is how you optimize for comfort, energy efficiency, and health at home.
Read the article: Controlling Humidity in Warm Climates