Space Saving Flexibility

The days of giant boiler and water tank rooms are diminishing. Building owners and operators need to maximize space to provide key functions and services, whether a building is a hotel, restaurant, school, or brewery. Because they don't store water, tankless water heaters are by nature compact. Commercial tankless arrays can be free-standing, wall-mounted, installed in corner layouts, or even located outside the building. They can even be integrated with a storage tank for staged, planned replacements of old tank-style water heaters.

In commercial spaces, every square foot means income potential. Considering that tankless systems require up to 80 percent less space than storage tank units, this can substantially increase available square footage. Realizing these space savings can benefit a retrofit project, and that flexibility can also be helpful in new construction.

For example, the initial plans for a new student apartment complex for Utah Valley University in Orem called for multiple water heaters and 5,000-gallon storage tanks. However, after realizing the potential for saving space, the plans switched to tankless water heaters. Today, eight tankless units with a total capacity of 14,500,000 Btu per hour supply generous hot water for the 450-unit complex while taking up much less square footage. This smaller footprint allows the university to use the extra space for several priorities, including residential and office space, other amenities, and a place to store the snow-melting equipment.

Graphic courtesy of Propane Education & Research Council

Tankless water heating's flexibility means arrays can be configured to provide reliable hot water to a small restaurant, a mid-size hotel, a college dorm, or a vacation resort. These are real-life examples.

Tankless Water Heater Arrays

In many commercial tankless systems, the capacity of an individual tankless unit is roughly 199,000 Btus. By combining these units in larger configurations, tankless arrays can provide hot-water output rates of several hundred gallons per minute. Tankless units can be arranged in self-supporting or wall-mounted racks, depending on the project's needs. Linking a system of multiple tankless water heaters together used to be a time-consuming process for contractors. But in recent years, manufacturers have simplified the process with tankless water heater arrays or racks: free-standing or wall-mounted multi-unit systems shipped to projects fully assembled, including gas and water manifolds. Depending on the application, manufacturers can customize these arrays to prioritize reliability, space savings, energy efficiency, or first-hour water delivery, including combining tankless units with storage tanks where appropriate. That's a vital service, as different types of commercial buildings have vastly different needs.

Venting Options

Propane and natural gas tankless water heaters require venting to exhaust combustion gases, and manufacturers offer a variety of venting innovations to simplify installation. For example, multiple units can use a common vent system that reduces space needs, labor and materials, and building penetrations. Traditional tank gas water heaters vent through the roof through a natural draft, with the hot exhaust air rising up and out of the building. Tankless water heaters' vents, by contrast, can terminate on a side wall because their combustion fans blow exhaust from the units horizontally or vertically. That fact is particularly helpful when remodelers or professionals replace expensive-to-operate electric tanks (which don't require venting) with natural gas or propane tankless units.

Installing a tankless water heater outdoors in warmer climates is simple, with no additional venting required. Replacing a tank water heater with an outdoor tankless system can also free up indoor floor space, with up to 9 square feet freed up on the floor. Tankless units are designed to withstand below-freezing temperatures through self-warming capabilities that prevent freezing and cracking. However, indoor installations are a better option in freezing climates where electrical outages occur.

While commercial and large residential applications may use multiple tankless units, they don't necessarily require two vent penetrations per unit. Manufacturers have developed a common-venting system that uses a manifold to share the same exhaust and intake vents for multiple tankless units, a useful option for projects where architects and builders want to avoid extra penetrations in the building envelope for practical or aesthetic reasons.

Flexible systems for Various Applications

Here are examples that show the flexibility for various commercial scenarios:

Planning a Retrofit/Replacement Before an Emergency

Just as hot water demand typically peaks during a 24-hour period, the demands on the commercial operation also ebb and flow. In a dormitory, demand peaks during the school semester and lessens during holidays and seasonal breaks. In hospitality, demands are greatest during certain months and less during others, depending on the weather patterns, holidays, and nearby events. Because of this ebb and flow in demand, the retrofit or replacement of an aging or inefficient hot water system can be planned to correspond with the low season so that an emergency doesn't occur during the high season when the stakes are more significant. Planning the retrofit allows ample time to determine the right system for the application.