Moisture control and dehumidification are increasingly hot topics among residential builders and property managers in hot-humid climates. I recently spoke with a couple of our manufacturer partners with NGBS Green Certified Products to learn more about the industry trends they’re seeing, and the solutions their companies are implementing to ensure energy-efficient green homes maintain proper moisture and humidity.
Nikki Krueger, Building Science & Business |
Brian Smith, Co-Founder, Innovative Dehumidifier |
What’s the general interest level in home dehumidification now, and what are you hearing from customers and others?
Krueger: Since we started offering whole-house dehumidifiers in 1996, our brand has seen steady growth. Advancements in construction practices and the increased energy efficiency of HVAC systems, has brought to light the need for dedicated dehumidification. I would say in the last 5 years there has been tremendous growth, as builders and developers have recognized that over-cooling to dehumidify is often not the most effective and efficient solution to controlling humidity in homes.
Smith: Interest is extremely high right now. Our sales have doubled every year since 2013 when we started our in-wall dehumidifier business. I attribute this to increased consumer awareness. As people become aware that there is a solution for the humidity issues in their homes, they are excited about that.
What’s the primary concern your customers are addressing?
Krueger: As we tighten our homes to comply with code, energy efficiency standards, and green building program requirements, we prevent air infiltration from the outside so the HVAC system doesn’t have to run as much. This is really good for energy efficiency, but, on the flip side, it traps the moisture being generated inside. That, in combination with less A/C run time, results in less moisture removed from the home.
We need to ventilate our homes in order to achieve healthy indoor air quality. This will contribute to higher levels of moisture when it is humid outside. In mixed-humid and humid climates, exhaust-only ventilation systems are allowed by code. The exhaust-only systems that remove air from the home are most prevalent because they are the most inexpensive to implement. However, these can cause issues because for every cubic feet per minute (cfm) of air exhausted from the home, equal cfm air will be sucked in through cracks and holes. The house is always trying to balance the air. This air is not filtered or conditioned, and, in the humid months, will contain the moisture, and often the heat, from outside. When this moist warm air hits cold surfaces, it will condense, often leading to microbial growth and other indoor air quality problems.
Smith: It’s largely an issue with HVAC system efficiency. Let’s say that you take a soda out of the fridge and place it on an outside picnic table on a hot, humid day. What happens? A ring of water will collect on the can and then drop onto the table. You can imagine that the length of time that the soda was outside would affect the amount of moisture that was deposited. If the soda was only left outside for a few minutes, only a minimal ring of water would be deposited. This is like our HVAC systems. In the past, our HVAC systems were more inefficient. They would run for hours on end and remove moisture from the air as they ran. Now, systems are more efficient. They may run for 2 minutes and then shut off. This saves energy and money, but it means that we need to find another way to manage our moisture issues.
Here’s another example – in the past, homeowners with well water would sometimes keep a light bulb in their wells. The light bulb would generate enough heat to keep the pipes from freezing in the winter months. Heat generation wasn’t the primary purpose of the light bulb. It was secondary benefit. Today, light bulbs wouldn’t be able to serve that same purpose, because they have become much more efficient and do not produce heat. Similarly, moisture management was a secondary benefit of HVAC systems that has been diminished due to the more efficient operation of those systems.
Are the issues you’re hearing about different for single-family and multifamily?
Krueger: Both single-family builders and multifamily developers/owners want to control moisture.
Single-family builders seek to differentiate their homes. “Healthy homes” sell faster and for more money than standard homes. Custom builders are on the cutting edge; they’re focused on offering superior “comfort systems.” Production builders are also increasingly showing an interest in designing for dehumidification.
For multifamily, interest in dehumidification is largely motivated by property and reputation protection interests. Property owners cannot control how their tenants live in their apartments, and there is typically a communication delay regarding moisture issues that can disrupt the comfort and health of residents and present a real liability concern for the property owner. By installing features and products, risk is reduced.
Smith: In multifamily communities, there are several tenant behavior considerations that can influence moisture issues including...
What products and building practices can be installed/implemented to address dehumidification?
Krueger: I think ducted dehumidifiers are the best solution, when possible. These systems are positioned in a central location and supply dry air throughout the entire home, providing superior control and comfort. For multifamily, mechanical closets are often too small to accommodate the ducts required for these systems. In-wall systems are designed to be installed within an interior wall, which avoids that issue.
Smith: For a long time, there wasn’t a true solution. There were portable dehumidifiers that could be purchased from home improvement stores. These proved to be more useful for flood events and tended not be run on a regular basis. They were problematic for several reasons, including being noisy, in the way, using a lot of electricity, and being inconvenient/labor intensive (need to be emptied when they are full).
Whole-home dehumidifier systems that were designed to work in conjunction with the HVAC system also presented problems. For example, if tenants chose not to use the HVAC system, they couldn’t run the dehumidifier system. Also, the systems required significant wall space for installation, which was often not available. And last, but certainly not least, they were very expensive!
Now, in-wall dehumidifier systems are designed to address moisture issues without any of these operational issues people experienced with previous solutions.
What should developers consider when evaluating in-wall dehumidifier options?
Both Krueger of Ultra-Aire and Smith of Innovative Dehumidifier indicated that in-wall dehumidifier systems are most commonly specified for affordable, student, military, and senior housing but are beginning to be specified for market-rate multifamily communities. Ultra-Aire manufacturers the MD33 In-Wall Dehumidifier, and Innovative Dehumidifier manufacturers the IW-25 In-Wall Dehumidifier, both of which are NGBS Green Certified as in-wall dehumidifiers that can maintain humidity below 60%. A key feature of these products is that they have a tamper-proof cover that is inaccessible to tenants or occupants, allowing a property manager to maintain control of the system operations.
Krueger: Important considerations for many buyers are - what company is making the dehumidifier and if their manufacturing facilities are located in the U.S. Other factors to consider are price, efficiency, and length of warranty.
Smith: Some companies are more solution-oriented and will explore moisture issues before recommending a product. A company that does direct customer sales, as opposed to selling through a distributor or retailer, can be more hands-on and provide technical recommendations, which is important to many of our customers.
If you are designing a single-family home or multifamily building in a hot-humid climate, consider these in-wall dehumidifier options, whether you are seeking NGBS Green Certification for the home or are just looking to provide homeowners and tenants with the most comfortable, healthy indoor environment possible. Be sure to check out these and all the NGBS Green Certified Product listed on our website – get the benefit of a pre-verified product that meets the requirements of the National Green Building Standard.
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