DHW Sizer is a data-driven tool designed to support the decarbonization of existing buildings by enabling accurate domestic hot water system design. One of the biggest challenges when replacing or upgrading a hot water plant in an existing building is understanding the true hot water demand. Without reliable information about the building’s load profile, designers are often forced to rely on assumptions, which can lead to oversizing, higher capital costs, and less efficient system performance.​
​
Proper sizing requires understanding several key factors. First, designers must understand how hot water demand varies throughout the day. Second, the system must include the right amount of thermal storage to meet peak demand while maintaining efficiency. Third, the heating capacity must be sized appropriately so that storage tanks can recover within a reasonable time after periods of high use. Finally, re-circulation losses must be evaluated so that the correct amount of heating capacity can be allocated to offset those losses.
Recirculation losses are particularly difficult to estimate in existing buildings. In many cases, the exact length of the recirculation loop, the piping layout, and the insulation quality are unknown. Without measured data, it can be nearly impossible to accurately estimate the heat loss occurring in the loop.
​
DHW Sizer solves this problem by collecting real operational data directly from the building. The system can be installed temporarily to monitor domestic hot water usage over a defined period of time. The collected data allows designers and engineers to understand the building’s actual demand patterns, storage requirements, and recirculation losses. With this information, the new hot water system can be sized accurately for both storage capacity and heating performance.
​
Getting the sizing right is critical for cost optimization. When designers rely on assumptions, systems are often oversized to avoid risk. While this may provide a safety margin, it increases equipment costs and often results in less efficient operation. By using measured data, DHW Sizer allows designers to confidently specify a system that matches the building’s real needs.
​
The DHW Sizer platform uses a custom data collection kit that includes a programmable logic controller (PLC), precision flow meters, and a cloud connection via Wi-Fi or LTE. This system continuously gathers operational data from the building and converts it into actionable sizing information for engineers and specifiers.
DHW Sizer is especially valuable for utility programs and decarbonization initiatives that are focused on upgrading existing buildings. By providing accurate, real-world load data, the platform enables designers to transition buildings to high-efficiency or heat pump-based hot water systems with greater confidence and better performance outcomes.