Hot Water Amenities
As the push for electrification and carbon reduction accelerates, Heat Pump Water Heaters (HPWHs) are emerging as an essential solution for domestic hot water in both new and existing buildings. HPWHs offer significant energy savings, lower greenhouse gas emissions, and increased alignment with progressive energy codes and adopted environmental protocols.
THE SCIENCE OF HPWHs
Heat pump water heaters use electricity, coupled with refrigeration cycle, to move heat—rather than generate it directly—making them two to four times more efficient than conventional gas or electric resistance water heaters. They pull heat from the surrounding air (air-source) or from a building’s condenser loop or hydronic return water (water-source), using that energy to heat water stored in tanks.
They heat water slowly but efficiently, using a larger storage tank to ensure hot water is available during peak usage times. These systems can integrate well with demand response to run when electricity prices are lower—during off-peak hours—which may save money on energy bills.
DESIGN CONSIDERATIONS & INTEGRATION STRATEGIES
Location & Ventilation Requirements
Air-source HPWHs require access to large volumes of fresh air and should be placed either outside or in mechanical rooms with adequate louvered ventilation.
Space Planning
Expect to reserve more space than with conventional water heaters due to larger tank sizes. Mechanical rooms may need to be expanded or reconfigured compared to previous designs. The large volumes of water may also have structural considerations depending upon the building.
Maintenance & Operations
Routine tasks like cleaning filters and checking condensate drains can often be handled in-house while potential refrigerant-related service may need to be performed by licensed professionals. Integration with a BAS (Building Automation System) allows better scheduling and optimization.
Advanced Integration
For larger buildings, campuses, or tech facilities, HPWHs can be part of a water-to-water heat recovery loop, recapturing waste heat from condenser or chilled water systems to preheat domestic water. These design strategies reduce energy use intensity (EUI) and lowers the site’s overall carbon footprint.
Regulatory Context – Washington State
The 2021 Washington State Energy Code limits the use of electric resistance and fossil fuel-fired water heating in new buildings and retrofits, strongly favoring HPWHs, with some exceptions.
Leasing Implications
A new HPWH system commands more space than traditional solutions. For high-rise tenant improvements, this becomes a sticking point for amenity spaces that rely on domestic hot water (showers or cafes). Additional tenant allowances may be required for equipment located on the rooftop, garage spaces, or fit within the landlord’s mechanical rooms with louvers.
As part of a building refresh, the client retrofitted its workspace by adding premium amenities, including a new café and locker rooms with hospitality-grade comfort. This came at a time when the client had adopted aggressive carbon emissions reduction goals across its real estate portfolio. Concurrently, Washington State’s energy code required the use of heat pump water heaters for new hot water loads in commercial buildings, eliminating the option of traditional electric resistance water heating systems.
Located in a downtown high-rise, the designated space lacked access to outdoor mechanical space for an air-source HPWH system. Assessing the space’s proximity to viable locations, the parking garage proved it could support the equipment while allowing access to proper air flow. To deliver hot water to the café and locker rooms located multiple floors above, a low-impact vertical pathway was integrated by using existing shafts and aligning new runs with the building’s structure. This strategy mitigated unnecessary disruptions and preserved valuable program space.
Hot Water Heat Pump Configuration