Energy-Efficient Hand Dryers  

All buildings need restrooms, and everyone who owns, operates and uses them can appreciate those that are well designed. Part of the definition of good design includes attention to the efficiency and sustainability of the components that make them up. Often, green building design focuses on the water, using component of restrooms, which, while important, is not the whole story. Considerable attention is also focused on how to provide hand drying that is effective and sanitary for users while providing energy and cost efficiencies for owners and building managers. Understanding the options and the implications of hand drying decisions contributes to the creation of greener, more sustainable restrooms and the buildings they are located in overall.
 
Restroom Design Influencers

Restrooms are necessary, but they can also be costly. In fact they could be the most costly rooms in a building on a comparative square foot basis since there are more built-in fixtures, features, and equipment there than most other spaces. Add in the fact that these rooms are often the most used and need to be finished in durable materials that are sanitary and water tolerant, and the construction costs get compounded further. Beyond these initial costs, however, there is the need for daily or sometimes even hourly maintenance, cleaning, and replenishing of supplies. This means that they continue to generate costs to the owner or manager every day that they are in use.

Architects working on the design of restrooms who are sensitive first to meeting the functional needs of restrooms but second to also understanding the ways to control efficiencies and costs can create designs that truly achieve both. To begin with, there are a number of fundamental pieces of information needed to create successful and sustainable designs. It starts with the nature of the building. A stadium or concert hall is obviously quite different from a retail store in their restroom needs even though they are both public places. An office building with employees present for long hours is different than a doctors’ office building with patients coming and going. Confirming and clarifying the real pattern of the people using the building will directly influence the need and design of restrooms that are there to serve those people, often well beyond the code minimum requirements that dictate fixture counts. The demographic make-up of the people using the restroom will certainly come into play as well. A single gender facility with occasional visits from the other gender will need a different balance than those commonly visited equally by both men and women. A facility that serves predominantly handicapped or elderly users will need more restroom amenities than the standard ADA or code minimums to properly meet those needs. And of course, the anticipated use level on an hourly, daily, weekly, or other basis needs to be understood to appropriately address not only the restroom size and layout, but also the effective pattern of people using those restrooms. Since there are often real peak times of use related to other activities in the building, the final design needs to address those peaks, or bear the critique of those waiting in the lines that may form as a result. All of this will likely influence not only the number of restroom fixtures and supporting equipment but also help determine their best locations.

Sustainable restroom design includes the selection of energy-efficient hand-drying equipment. Photo courtesy of World Dryer, Inc.

With the above basic information in hand, the architect can also assess some other general restroom needs including the following:

Noise Considerations
People, fixtures, and equipment all make noise. Different building types have different tolerance levels for that noise as it relates to the overall indoor environment. Therefore, the appropriate level of attention should be paid to noise control or reduction based on the needs of the building and the users. Of particular note, the US Green Building Council LEED® rating system has recently identified noise control as a factor for indoor environmental quality, particularly in schools. They have gone so far as to identify noise levels in and between selected rooms, especially between classrooms and adjacent rooms. Therefore, increasing attention is being paid to containing the noise levels within restrooms.

Handicapped Accessibility Compliance
All public and most employee restrooms need to meet handicapped accessibility standards as covered in the Americans with Disabilities Act (ADA) or in building codes that reference ICC-ANSI 117.1. Such compliance extends beyond just paths of travel, turning radii, and grab bars. It also applies to all of the fixtures and equipment located in the restroom that is designated to serve physically handicapped persons. In particular, mounting heights need to be specified and protrusions from the wall need to be limited—or in some cases recessed into the wall. Hence, compliance goes beyond design layouts and extends to specification of equipment as well.

Hands-free or touch-free operation of restroom equipment and fixtures helps assure improved sanitation. Source courtesy of World Dryer, Inc.

Sanitation
Heightened public awareness of dangerous infections such as MRSA and HlNl has contributed to a heightened scrutiny of restroom hygiene. Because of this, terms such as "hands-free" and "touchless" have become commonplace among building managers and users. The reality is no one wants to touch something where someone else's bacteria-laden hands may have been. Therefore, facilities managers are seeking alternatives such as motion-sensor soap dispensers, automatic faucets and touchless hand dryers that help eliminate the need to touch surfaces. Of course, hand hygiene plays a fundamental role in minimizing the spread of infectious diseases, bacteria, viruses and parasites. Dangerous microorganisms and bacteria harbor on the surface of the skin; however proper hand washing with soap and water, coupled with sanitary hand drying techniques, can dramatically reduce the spread of harmful disease and bacteria-especially in highly public areas such as food preparation facilities, educational institutions, and clinical/medical environments.

Finger and Water Ingress Protection
Any equipment with openings where hands come into contact with it is prone to accidently having fingers etc. get stuck in those openings. Some equipment can also be prone to exposure to water infiltration or ingress not just from normal usage but from washroom cleaning processes and protocols. For example, some facilities routinely wash the floors and walls with a hose and water spray, meaning that anything on the walls is subject to getting hit with that water spray. The National Electrical Manufacturers Association (NEMA) working in conjunction with the International Electrotechnical Commission (IEC) has established standards that address both of these ingress concerns with an Ingress Protection (IP) rating for equipment, particularly for any electrical equipment. The IP rating is a 2 digit number after the letters IP where the first digit rates protection against objects entering the unit and the second rates protection against water ingress (or water entering the unit). So, in the case of restroom equipment, a rating of IP24 for example is desirable. The first digit of “2” means that objects the size of fingers or similar will not fit into openings while the second digit of “4” means that water will not penetrate when sprayed or splashed in any direction. For more information on this topic and the NEMA IP ratings, see:  http://www.nema.org/Products/Documents/nema-enclosure-types.pdf. For a summary of the IEC standard adopted by ANSI in this country, see:  http://www.nema.org/Standards/ComplimentaryDocuments/ANSI-IEC-60529.pdf

Ingress Protection (IP) Ratings are assigned for differing levels penetration resistance – the second digit of the rating indicates the ability of an electrical product to resist varying levels of water conditions. Source: World Dryer, Inc.

Service Life
It is a safe bet that equipment and fixtures will likely not last as long as the building itself, meaning that they will need to be repaired or replaced either by need or desire at some point. Planning for a service life that is as long as possible not only keeps costs under control, it contributes to the long term durability and sustainability of the restroom and the building. Most equipment is manufactured for a specific number of uses, meaning that a high frequency of use in a high traffic restroom (e.g., airports, schools, etc.) will use up the planned number of uses quicker, thus creating a shorter service life. Selecting equipment that is suited to its level of use will obviously maximize the time that it remains in service before needing to be replaced. A contributing factor to longevity is the ability of the equipment to resist corrosion since restrooms create conditions that can corrode unprotected materials. Therefore, any equipment or fixtures need to be manufactured to resist this corrosion in order to operate properly over time without premature failure. Finally, certain restroom environments are prone to vandalism for whatever reason. Recognizing that reality and selecting equipment with features that can slow or deter vandalism will certainly contribute to the continued use and operation of equipment without premature disruption.

The above design parameters and criteria form a general basis that is applicable to the overall restroom design and its individual parts. One aspect of the design is worthy of particular attention due to its impact on both facility operations and green building principles—hand drying.

Hand Drying Options

Everyone who uses a sink in a restroom needs and wants to dry their hands conveniently and effectively at the same time. Traditionally there have been two options available to designers for this function: paper towels or traditional air dryers. More recently, however, a third option has emerged with growing popularity, namely the use of high-speed, energy-efficient air dryers. Each of these three choices is discussed in more detail below:

Paper Towels
Commonly considered as popularly preferred among restroom users, paper hand towels are usually quite unpopular with restroom cleaning staff and facility managers. The reasons have to do with the need to dispose of them after use, then to continually replenish them, and the resultant ongoing costs of that disposal and replenishment. From a green operations and management standpoint, it should be noted that they have an inherent flaw. While they can be purchased with a respectable amount of recycled content, they typically are not eligible in most communities for then being recycled again. Instead, they must be sent to the waste stream either for incineration or placement in a landfill, both of which are preferred to be avoided. According to the US EPA, it is estimated that approximately 3,000 tons of tissues and paper towels end up in US landfills every day. That equates to as many as 51,000 trees per day to replace the number of paper towels that are discarded daily. The embedded energy and resources in the paper towels is also significant with each ton of paper produced typically requiring on the order of 7,000 gallons of water, 360 gallons of oil and 158 million BTUs to produce.

From a practical standpoint, paper towels present other issues as well. Containers to hold the waste towels need to be designed into the restroom layout so they are conveniently accessed by users, but not subject to abuse. Maintenance staff will require ready access to retrieve those containers and empty them of course, but also to keep them clean since this is now the repository for bacteria and germs wiped from the hands of users. The timing of the maintenance activities needs to coincide with the actual usage level too, since it is quite common for trash receptacles to overflow with paper towels creating not only an unsightly situation but an unsanitary one. In addition, the very presence of paper towels sometimes invites unwanted use and activity causing clogged toilets and sinks. This creates further maintenance and monitoring issues that detract from other duties.

Regarding budgeting, a number of simple studies have been performed to look at the cost of using paper towels. To purchase the paper towels, whether in roll or folded form, most facility managers pay on the order of 1 to 2 cents apiece. Consider that the typical user takes an average of 2.5 towels per visit meaning that every 100 daily users consumes 250 towels costing $2.50 to $5.00 or over $1,000 per year. A high use setting such as a university campus could well have 40,000 daily restroom visits across multiple buildings and restrooms. Even if the paper towel cost per visit were only 1 cent, that would add up to $400 per day and for the days the university is in operation could cost on the order of $75,000 per year or more. Add the cost of delivering the clean towels to the restrooms plus removing and disposing of the used ones, and the full cost is much higher. These are significant dollar amounts that could readily be spent on other maintenance items no doubt.

In short, the use of paper towels for hand drying has significant implications not only on the restroom design, but also on the ongoing operation and maintenance of the restroom. Further, their environmental impact is notable in terms of materials and waste management and the embedded resources used to create them.

Traditional Air Dryers
Recognizing the limitations of paper towels and seeking to eliminate the waste and cost they embody, electric hand dryers that use heated air have been in use for decades. These manufactured pieces of restroom equipment have been developed to be reliable and long lasting with durable components and materials that have proven to hold up to the rigors of many restroom settings. Manufacturers typically point out that these standard hand dryers boast long motor life and quiet sound design that are suitable for high traffic facilities needing vandal resistant features. They are offered in models that satisfy handicapped accessibility requirements by being recessed into the wall. And in the interest of hygienic operation, they are offered in touchless sensor operation models in addition to the classic push button version.

As many people have observed, however, their inherent strengths come at the cost of some limitations too. From a user standpoint, they don’t dry hands as quickly as paper towels, sometimes taking up to 30 seconds to achieve satisfactory dryness. In locations where both paper towels and traditional hand dryers are offered, both will likely be used as a result. From the standpoint of the building owner or manager, they consume energy, sometimes more than desired. The blower fan is one source of energy consumption but so too is the electric heating coil, the combination of which can require on the order of 2,300 watts and a dedicated 20 amp circuit. Further, while these units will have ingress ratings using the IP codes, they are often not rated for finger protection and only minimally for water infiltration.

Overall, traditional air hand dryers serve certain situations quite well when use is limited, durability and vandal resistance are paramount, and paper towels are meant to be avoided. They come with limitations though related to the time it takes to dry hands and the amount of energy they use in the process. Nonetheless, they have set the stage for the next generation of air hand dryers that are overcoming some of these limitations while garnering even more benefits.

High-Speed, Efficient Air Dryers
The emergence of high speed air hand dryers has changed the way many people think about alternatives that can eliminate the waste and cost of paper towels while still meeting user satisfaction. In the process, manufacturers have responded to the need for greater energy efficiency and customization of products to suit different restroom situations.

Compared to their traditional hand-drying predecessors (left), high-speed energy-efficient hand dryers (right) are a preferred choice due to their shortened drying times, greater energy efficiency, and contemporary exterior appearance. Photo courtesy of World Dryer, Inc.

The most notable improvement over traditional hand dryers is the optimization of air performance, which allows for shorter hand drying times. This is achieved in part by more than doubling the air velocity (speed) even though the quantity of air (CFM) is about half that of a traditional hand dryer. The result is that hands can be dry in as little as ten seconds, or three times faster than traditional hand dryers. That puts them on par with the time it can take to dry hands with paper towels.

Improved energy efficiency is achieved in a number of ways. The shorter dry times mean that the dryer is turned off longer using inherently less energy right off the bat. Improvements in the efficiency and design of the electric motor also contribute significantly to energy savings. Further, some manufacturers are offering these new dryers with three-speed power and sound control settings that can be optimized for energy efficiency and user comfort. The power/sound level can be adjusted at high for high traffic restrooms, at low for quiet and low traffic locations, or medium for those in between. The range of electrical demand can vary then from 400 to 1,250 watts or a dramatic decrease from traditional hand dryers that draw 2,300 watts. The range of sound will also vary between 73 to 85 decibels depending on the control setting. Further, the heating element can specified to be switchable allowing it to be turned on in cold weather locations or off in warm weather locations. As a result, it is now possible to specify an electric high speed hand dryer that uses up to 88 percent less energy than traditional hand dryers.

With the increased efficiency and higher acceptance of high speed dryers, building owners and managers can now realistically eliminate paper towels and save dramatically on operation expenses. Even at the rate of 10 cents per kilowatt-hour the cost of using these high-speed dryers is a whopping 99 percent less than the cost of using paper towels. Of course, by eliminating the paper towels altogether, 100 percent of the cost of the waste is eliminated not just for the facility, but for the environment as well.

The cost per dry is commonly calculated showing high-speed energy-efficient hand-dryers with a 99% or better savings compared to paper towels. Calculations are based in this case on average paper towel cost of $0.0152 for one sheet or 1 foot per dry; average commercial price of $0.10 KWH reported by US Energy Information Administration in 2009. Photo courtesy of World Dryer, Inc.

 

Green Building Contributions of High-Speed Hand Dryers

The green building movement in this country has given rise to quantifiable rating systems that seek to establish specific levels of achievement in the creation and performance of green buildings. The best known of these green building rating systems has been developed by the US Green Building Council and known as the LEED® rating system. This is actually a family of ratings that apply to different building situations (e.g., new or existing buildings, core and shell, interiors) and in some cases building types (schools, healthcare, retail, homes, etc.). All of the LEED rating systems have been subject to ongoing changes and updates since their inception, but the basic categories of defining green buildings have remained the same across the different versions over time. With that in mind, the contributions that high-speed hand dryers can make fall into several green building categories:

• Optimize energy performance: High-speed energy-efficient hand dryers can be specified with internal controls that help optimize energy performance of the units and reduce energy use dramatically.

• Materials and resources: In the operation and maintenance of a building, solid waste planning and management is a prominent focus area. Using high-speed energy-efficient hand dryers eliminates the need to dispose of paper hand towels.

• Indoor environmental quality: High-speed energy-efficient hand dryers are pre-finished and require no additional painting or coating in the field. That means that the use of any VOC containing paints or coatings are eliminated. Further, the elimination of paper waste cuts down on the need and use of cleaning supplies to deal with that waste in restrooms.

• Innovation in design: Because of the replacement of paper towels with air hand dryers, innovative prevention of waste may be able to be shown. Additionally, these long lasting products demonstrate favorable life cycle analysis while their use reduces the transportation and embedded energy used in hand drying. It may also be possible to demonstrate innovation for retrofit applications.

Specifying High-Speed Energy- Efficient Hand Dryers

As noted previously, specifying the appropriate hand drying product means recognizing that one size does not fit all situations. Today's hand-dryers offer many more available options and features than their earlier predecessors. Specific hand-dryer features to consider in order to address client requirements while creating an environmentally responsible restroom include the following:

• Automatic operation versus push button: Manufacturers have responded to consumer preferences not to handle something that others already have by minimizing the need to touch any surface in a public restroom whenever possible. Automatic “touchless” operation is clearly preferred anywhere that sanitation is given a high priority such as restaurants and high traffic area restrooms. Touchless hand dryer models prevent cross-contamination from buttons, knobs and levers, proving to be more sanitary than other hand drying alternatives. As an added measure of sanitary control, some of the newer air dryers feature embedded anti-microbial additives that use disinfectant substances to kill or inhibit the growth of microorganisms such as germs, mold, and bacteria as a way of further improving the hand hygiene process. In fact, studies have shown that antimicrobial technology is 99 percent effective against e-coli and MRSA.

• Drying speed controls: One of the biggest advantages of the newest hand dryers is the opportunity to specify them to be adjustable to suit different restroom settings. If this feature is not needed, then single speed models are still available, but having options to change the air flow and the resulting sound levels from location to location without having to keep track of multiple models of dryers certainly makes maintenance and facility management easier. Faster speeds help to ensure adequate drying that avoids the risk of water- based transfer of contaminants while slower speeds reduce noise levels. Manufacturers have commonly built in control switches under the housing that can be accessed by maintenance staff and adjusted accordingly.

High-speed, efficient hand dryers can be specified with intelligent drying controls to suit their location and save energy. The power/ air flow level can be adjusted at high for high traffic restrooms, at low for quiet and low traffic locations, or medium for those in between. The heating element can be switched on in cold weather locations or off in warm weather locations. Photo courtesy of World Dryer, Inc.

• Temperature controls: Similar to speed control, air temperature control during operation is desirable for comfort and energy efficiency. During cold weather, heated air in hand dryers is usually welcome, although it may contribute to dry skin. In warm weather times, the heat may not be needed or welcome. In that case, having the ability to switch off the heat altogether is advantageous to everyone while reducing energy use further.

• Single- or multiple-opening nozzle: Many manufacturers offer units that have multiple port nozzles that will spread air across a wider hand drying area than a single port nozzle. This may be more comfortable for users since it more evenly disperses the air across hands, but it also affects the drying speed and velocity of the air. Hence, different models that use these different technologies should be compared appropriately.

Multi-port hand dryers (left) have more openings to evenly disperse air across a larger area onto hands compared to single-port hand dryers (right). Photo courtesy of World Dryer, Inc.

• Sound quality and level: The higher the speed of the air, the louder the sound generated. In areas where noise control is needed, then either an adjustable setting should be specified or a unit needs to be selected that falls within the acceptable sound range. The alternative, of course, is to address the sound control qualities of the restroom itself to contain any noise within and not transmit it to adjacent spaces.

• Voltage requirements: Manufacturers offer hand dryers with a range of standard voltages including some models that can operate at universal voltage. Common voltage designations of 110/120V, 208/240V and 220/240V are available with decreasing amperage requirements naturally as voltage increases.

• Handicapped accessibility standards compliance: There are a variety of surface mount and recessed units that are available that meet ADA and ANSI 117 handicapped accessibility requirements. Surface mount models with a slim profile are specifically available from some manufacturers that meet these requirements while saving on the cost and labor associated with recessing the units into a wall. The performance factors of some of these units should be scrutinized, however, since not all manufacturers use the latest high speed energy efficiency technology. In some cases, the best solution is to specify a standard high speed unit that is installed in a recessed enclosure, often available from manufacturers.

Typical surface mount hand dryers with a slim profile to meet handicapped accessibility standards eliminate the need for a recess kit and save on labor and installation costs. Image courtesy of World Dryer, Inc.

• Water ingress resistance (IP ratings): If the restroom is prone to use water spray or other high intensity cleaning, then these ratings become very important for safety and durability of the hand dryers. It will also help protect the inner, working elements of the unit and help improve longevity as a result.

• Life expectancy and durability: The overall unit needs to be specified to meet particular levels of durability and corrosion resistance to suit the restroom setting. Of particular note is the motor which is the operational part and commonly rated to a certain level of uses or hours of operation. Some manufacturers provide notably longer lasting, more durable motors than others, so it is worthwhile to compare.

• Serviceability: If a unit needs to be repaired rather than replaced, selecting one that can be easily serviced could make a difference not only in terms of operations, but in terms of overall sustainability and longevity.

• Warranty: As with all manufactured products, warranties on high-speed energy-efficient hand dryers vary, so they should be looked at carefully. Some carry warranties in excess of 5 or 10 years indicating their overall long life expectancy.

• Finish options: In the days of traditional hand dryers color choices were somewhat limited. The current generation of products offers painted cast aluminum or steel options that commonly include white or black. In addition, metal finishes are available in both polished and brushed chrome or stainless steel.

High-speed energy-efficient hand dryers are available in a range of colors and metal finishes including white, black, brushed metal, and polished metal. Photo courtesy of World Dryer, Inc.

Layout and Installation

Placement of hand dryers is important to be sure that they are conveniently accessible and appropriately functional. Hand dryers should be spaced at least 2 feet apart, near but not over the wash basin. In congested areas, dryers should be located to create a flow from wash basin to dryer to exit. Automatic sensor operated units should be placed more than 18 inches above or away from reflective surfaces which may interfere with the automatic sensor operation.

The appropriate quantity of hand dryers will vary based on the location of course. For average traffic, one dryer per every two wash basins is recommended. For heavy traffic restrooms, one dryer per each wash basin is more appropriate. In cases where industrial style circular wash centers are used, then four dryers per center are appropriate.

Recommended mounting heights for dryers are as follows:

• Men’s washrooms—46” (117 cm)
• Women’s washrooms—44” (112 cm)
• Children’s washrooms, ages 4-7—32” (81 cm)
• Children’s washrooms, ages 7-10—36” (91 cm)
• Children’s washrooms, ages 10-13—40” (102 cm)
• Children’s washrooms, ages 13-17—44” (112 cm)
• Handicap Mounting Height—37” (94 cm)

Electrical requirements for high-speed energy-efficient hand dryers typically include a 15 amp circuit.

The unit’s exterior surfaces can be cleaned in normal fashion using common bathroom cleaners and should be maintained to be free of any unusual or unnecessary substances. For low to medium washroom traffic, routine inspection of internal passages for cleaning and removal of debris impeding airflow is recommended every 12 months.  For high washroom traffic, inspection and cleaning of internal passages is recommended every 6 months.  Some units include disposable intake air filters to simplify cleaning and reduce cleaning time and effort.

Conclusion

Electric high-speed energy-efficient hand dryers are a sustainable, cost-effective choice for new and renovated restrooms. They have been shown to use up to 88 percent less energy than slower traditional hand dryers and up to a 40 percent difference between similar high-speed dryers. They use less energy than embedded in paper towels and cost notably less than paper towels or traditional hand dryers to operate. These new, updated products boast a longer service life on many models and use technology that promotes good hand hygiene and sanitation. Their contemporary designs are available in multiple finishes and work with many interior design schemes. Overall, they are a logical, preferred, and sustainable choice over paper towels that will benefit the users and the building owner/ managers initially and over time.

Peter J. Arsenault, FAIA, NCARB, LEED-AP practices, consults, and writes about sustainable design and practice solutions nationwide. www.linkedin.com/in/pjaarch

World Dryer, the global leading manufacturer of hand dryers for over 50 years, is the only manufacturer that offers you a full portfolio of fast, energy efficient, competitively priced hand dryers designed to fit the individual needs of any facility. www.worlddryer.com