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Let’s face it: traditional commercial water heating is inefficient. Based on the 2018 Commercial Buildings Energy Consumption Survey(CBECS), the estimated 5.9 million commercial buildings in the U.S. consumed 6.8 quadrillion BTUs of energy and spent $141 billion on energy. Five percent of this total energy consumption went to water heating.
Traditional commercial water heaters come in two basic designs: a standard tank or a boiler with a side-arm tank. Neither provides hot water on-demand. These systems produce large volumes of hot water 24/7 even when water is not being used, resulting in large standby losses over time. They also have poor heat transfer due to how the systems are typically designed, with heat transfer efficiency further reduced due to sediment and scale build-up. Compounding the problem is that two inefficient systems are often installed for the sake of redundancy and reliability.
Benefits of Propane Tankless Water Heating
Propane-powered commercial tankless water heaters overcome these deficiencies with on-demand hot water, improved energy efficiency, and space savings.
On-demand hot water
Instead of storing water, tankless systems use a heat exchanger to heat water just as it’s needed in a building. For example, when a guest turns on a shower in a hotel, a propane or natural gas burner in the tankless unit quickly heats up the heat exchanger; in very high-efficiency models, incoming cold water is preheated from the combustion exhaust. Then the water continues to be heated as it passes through the unit’s heat exchanger and exits from the tankless unit at the hot-water outlet pipe, where it then flows to the shower to meet the hot water demand.
Meets a wide range of load types
Commercial tankless water heaters have the versatility to meet a wide range of load types and can be installed as a single unit or a large array. When individual tankless units are combined into larger configurations, it allows them to provide hot water rates of several hundred gallons per minute and handle water heating no matter the size or scope of a building.
Intelligence and performance
Computerized controls allow tankless water heater arrays to precisely track the water-heating load of a building and activate individual units accordingly. Those controls make it possible for the tankless system to ramp up to meet a building’s peak load and then ramp back down so just a single unit is active. AI built into some manufacturers’ units analyzes a building’s hot water usage patterns, identifying and predicting the timing of peak loads so that the units can fire up and activate a building’s recirculation system in preparation for the higher hot water demand.
Energy efficiency
Propane-powered tankless units also don’t waste energy heating large volumes of water around the clock. Whereas a storage tank system has to be designed for a building’s peak load and keep a full tank constantly heated, a tankless system can rely on just a portion of the tankless units during off-peak times. They remain very efficient even when running at less than full capacity. As the hot water demand increases, the tankless water heater can increase its combustion rate. When demand gets even higher, the system controller will turn on another tankless unit and share the demand across both units. Tankless water heaters with Energy Star certification have the potential to use 25% less energy than a conventional commercial water heater.
Space savings
Tankless systems take up significantly less space than traditional tank units or boilers and there is flexibility in placement. Commercial tankless arrays can be free-standing, wall-mounted, installed in corner layouts, or even located outside of the building, thus freeing up space for other uses.
Project Highlight: Rangeley Inn & Tavern
Lodging, healthcare, retail, education, food service, and office facilities represent about 85% of all commercial building water-heating energy consumption. Those building types also use 6% of the energy in the entire commercial buildings market. The hospitality industry in particular, has unique water heating needs. For example, hotels typically have long periods of inactivity of about 12 hours, followed by peak loads. Showers and laundry are the primary demand for hot water in these types of buildings, although laundry demand times usually differ from those of peak shower demand. The sizing and setup of water heating systems will vary based on the hotel or motel use, room types, and peak occupancy.
At the Rangeley Inn & Tavern in Rangeley, Maine, the tank-style water heater failed in November 2023 and owner Travis Ferland decided to choose a more sustainable option for the inn’s water heating needs. He had been working to boost the sustainability of the facility as a whole, so choosing a more efficient water heating system was a great place to start. Ferland says, “That has been a goal since I purchased the inn 11 years ago. I have gradually been making upgrades to modernize our HVAC and hot water systems to reduce cost and to reduce environmental impact.”
There were several other factors that drove Ferland to choose the tankless option. The inn is located in an area that isn’t serviced by natural gas, and it already uses propane in the kitchen and laundry room, as well as for two propane-fired boilers for forced water heat. The technician also noted a tankless unit would reduce maintenance costs and downtime. Two Intellihot Neuron iN501 drop-in tankless models (499,999 BTUs/hr) were installed. These are highly efficient commercial hybrid water heaters with a slim profile, in-unit redundancy, and lower capital and operating costs compared to boilers and tank-style water heaters. Travis notes, “I needed to increase capacity to prepare for the reopening of the inn’s long-shuttered third floor, which will bring 20 rooms back into service. This option made the most sense, from the perspective of maintenance and cost, but also for efficient distribution throughout this large, historic inn.”
These propane-powered tankless systems also eliminate the need to oversize and install redundant equipment. They are guaranteed to replace comparable boilers and even have the same connections as traditional boilers, which allows commercial properties and contractors to easily switch to Intellihot’s tankless efficiency. Other features include scale-proof heat exchangers and masterless cascading, which means each unit operates autonomously. Cascaded units do not require a master controller, which eliminates single-point failures that arise from the failure of the master controller, ensures zero downtime, and increases capacity. In addition, the smart units share information on run hours, firing cycles, and flow, then automatically rotate units to normalize wear and tear.
When Ferland was asked whether customers have noticed the endless hot water he laughed. “Guests don’t notice when hot water works—only when it doesn’t. The fact that we haven’t received any complaints is a testament to the system’s efficacy.”
Overcome Deficiencies, Find Efficiency with Propane Tankless Units
Propane tankless water heating units overcome most of the deficiencies of traditional commercial boilers and tank-style systems. They are highly energy efficient because they don’t store hot water, they have slimmer profiles, providing space savings and design flexibility, and they can be arrayed to meet a wide range of load types. Whether replacing a commercial water heating system or building new, installing propane tankless units will improve comfort, costs, and carbon emissions.
Watch to learn more about propane for commercial buildings.
