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Sizing Commercial Tankless Water Heaters From Stadiums to Skyscrapers: 3 Insights

Our commercial tankless water heaters have been sized/installed in 19,000+ N. American properties. These 3 insights from our database may surprise you.

Intellihot’s units have been sized/installed in 19,000+ N. American properties so far. This diverse portfolio includes skyscrapers like Chicago’s 340-On-the-Park and popular stadiums like this one in Santa Clara, California. However, unlike other manufacturers, our sizing calculator for commercial tankless installations guarantees its results.

340-on-the-Park and the Santa Clara stadium were sized with the same guaranteed approach. Yet, the glaring differences between the two properties were also considered. As surprising as it may seem, the precise use of data can result in a unified sizing approach for commercial properties that can be scaled for repetitive usage while ensuring customizability. Here’s 3 insights from our database that shed light on our approach:

Commercial tankless water heaters sizing by property type.

Hot water usage differs by property type.

Intuitively, it is not surprising that hot water usage differs by property type. However, consider the following: why do hospitals seem to need more hot water, on average, than hotels?

Hospitals not only use more quantities of hot water than hotels, but they also typically use hot water at a faster rate. Moreover, there is much more variance in property size for hotels in North America, compared to hospitals.

Commercial Tankless Water Heaters Sizing by Occupancy

Hot water usage differs by occupancy, but not linearly!

This chart shows the average flow rate (in GPM) needed by N. American hotels in 2023, broken down by the number of rooms. At first glance, the chart proves the general notion that hot water needs and usage increase by occupancy levels or “size” of the property. Yet, occupancy and hot water usage/need do not follow a linear relationship. Let’s dive deeper into this insight.

The above chart shows the average flow rate (in GPM) needed by N. American hotels, broken down by number of rooms and fixture counts. Why do you think the average hot water need for 150-180 room hotels with 0-100 fixtures is lower than 10-150 room hotels with the same fixture count?

Adjudging hot water needs with traditional categorization based on property size (fixture count/number of rooms) ignores several real-world considerations like temperature rise and elevation. Several properties might also require multiple temperature zones like a booster for the laundry. The following graph shows how hot water needs vary for hotels with different fixture counts and the inclusion of commercial washers.

Commercial Tankless Water Heaters Sizing by Theory of Diversity

A property's "worst case scenario" is not as scary as you think.

Traditional wisdom suggests sizing a hot water system for the “worst case scenario” or peak demand. However, the worst-case scenario would never involve 100% of a property’s hot water fixtures being open at the same time. Third-party data shows that the worst-case scenario is much lower than 100%. For hotels, the peak demand is only between 12-18% of all hot water fixtures being open simultaneously.

This facet is well-documented and referred to as “the theory of diversity.” Here are a few examples of peak demand for various property types:

How We Use These Insights for a Simpler Commercial Tankless Water Heaters Sizing Approach

While the above insights provide interesting insights into commercial hot water usage, their true usefulness is felt in simplifying traditional sizing approaches. Common sizing methodologies like the Hunter’s Curve method or the ASPE domestic design method force engineers to make standardized assumptions that lead to oversizing (which increases a project’s upfront and operational expenses). At Intellihot, we have modified these curves for our guaranteed online commercial sizing calculator. 

Using our database, we can predict the worst-case scenario for any commercial property regardless of its type, size, or geographic location without making any standardized assumptions. This approach has allowed us to size 19,000+ commercial properties instantly with a sizing guarantee. These properties have witnessed up to 30% reduction in operational expenses and up to 50% reduction in upfront costs. 

Want to learn more about our sizing approach? Download our ebook, “From Skyscrapers to Stadiums” to get more insights and learn how they tie into our larger sizing methodology that ensures  instant, guaranteed results at scale with exciting customizability. 

From Skyscrapers to Stadiums

How data helped us design custom commercial hot water systems at scale.

"We needed a high output water heater with a small footprint to supply hot water for the scrubbers in the stadium, and the Intellihot iQ1001's small footprint was great to install in the mezzanine."

From Skyscrapers to Stadiums

How Data Helped Us Design Custom Commercial Hot Water Systems at Scale