Supplemental Testimony of
Sierra Club District of Columbia Chapter
Hearing on Maintenance, Construction, and Environmentalism Regarding DPR Indoor and Outdoor Facilities and Spaces
Committee on Facilities
Held on January 16, 2026
The Sierra Club provides this supplemental testimony building on the oral testimony of Matthias Paustian on pools and responding to the issues raised during the hearing of the Committee on Facilities on Friday, January 16 on Maintenance, Construction, and Environmentalism Regarding DPR Indoor and Outdoor Facilities and Spaces
We would like to begin by recognizing the outstanding and really pioneering work that the DPR has already done in collaboration with DGS on net zero energy buildings in the District.
In 2021, the Stead Park Recreation Center renovation was completed as a net zero energy recreation center with a geothermal heat pump, and designed for a 75 kilowatt solar array. We now have measurements of how little energy the building uses: it saves about 60 percent of the energy it would have used under the baseline required per code. What a fantastic achievement. Similarly, DGS has built several schools to a net zero energy standard, including John Lewis Elementary School in Ward 4. Congratulations to DGS on that outstanding facility as well and to the many other net zero energy buildings it has built. We are deeply thankful for the excellent work here.
However, the approach we are observing from the executive in recent years have increasingly become hostile and antagonistic to the net zero energy initiatives that save the District government money on energy bills and reduce pollution from combustion of fossil fuels.
Most recently, the executive asserted that indoor pools cannot be built to the District’s net zero energy standard. Since the executive does not pinpoint the specific technical issue where the problem arises, we will engage with the most common reservations and respond.
A number of incorrect or misleading statements were made at the hearing about the requirements for a net zero building, and we would like to clarify the confusion those assertions created.
- A government witness asserted that the pass-fail test for a net zero building is whether the building can produce as much renewable energy on site as it consumes.
That's incorrect. The District's net zero energy standard in Appendix Z only requires 5% of the energy to come from on-site renewable sources. The rest can come from off site renewable energy sources, providing flexibility in meeting the standard.
- A government witness asserted the available roof space for installation of solar panels is often limited because of requirements to comply with stormwater management regulations.
The District's stormwater management regulation applicable to buildings that we are aware of is the Green Area Requirement established in 2013 by the DC Zoning Commission. That regulation explicitly allows for compliance by installing solar PV. In particular, the green area credits associated with installing rooftop solar (with a credit multiplier of 0.5) are almost the same as the credits for a vegetated roof (there’s a credit multiplier of 0.6 for vegetated roof with less than 8 inches soil depth of growing medium). Hence, a building can comply with either option almost interchangeably.
Furthermore, solar panels and vegetated roofs can be built jointly, since vegetation can grow under and next to solar panels that are installed with a tilt and spaced slightly farther apart than normal. In fact, the the Department of Energy and Environment’s Green Area Ratio Guidebook explicitly allows stacking of credits for solar jointly with vegetated roofs (along with all other elements indicated by the green squares in the figure below) on the same area, effectively recognizing that solar PV and vegetated roofs do not compete for roofspace but can occupy the same roofspace.
Source: DOEE Guidebook, page 77
The Green Area Requirement does not restrict the available roof space for solar at all. We encourage the committee to direct DGS to clarify in what way stormwater management rules restrict solar roof space.
- A government witness asserted that the space-constrained urban environment does not allow enough space for geothermal wells.
That is certainly true, but it is not clear what the implication is. Nothing in the law requires the use of geothermal wells. In fact, air source heat pumps are perfectly capable of heating an indoor pool and are highly efficient. A recent net zero energy pool in Toronto is heated with air source heat pumps. The DC government should use air source heat pumps in situations where space is an issue. Air source heat pumps fit on a small part of every building's roof. Heat pumps have a lower average seasonal efficiency than ground source heat pumps, but how much the lower efficiency matters for achievement of the net zero requirements under Appendix Z depends on the overall building design.
Challenges in meeting the net zero standard for natatoriums
Pools can be built to a net zero standard, as documented in various net zero guides for pools. However, Sierra Club acknowledges that buildings with pools are more challenging to construct to a net zero standard than schools for the following two reasons.
- Higher indoor design temperatures
Buildings with indoor swimming pools are designed to have a higher indoor temperature than a residential building. A typical indoor temperature in a school is around 70 Fahrenheit, compared to around 80 Fahrenheit for a pool. This raises the heating demand by around 33 percent. By the same logic, it reduces cooling demand if the indoor pool is operated year-long.
Source: 2019 ASHRAE Handbook: HVAC Applications
- Dehumidification.
Large amounts of water evaporate during normal pool operation, requiring ongoing operation of dehumidification equipment far in excess of what is typical for residential buildings. Under ideal conditions, dehumidification raises the overall energy use but not the heat load (because dehumidification allows for near complete heat recovery when done right).
Below we outline how these two special features of pools affect the three key requirements under the District’s net zero energy code.
- Thermal energy demand intensity (TEDI) <= 4.2 kBTU/sq. ft. per year.
This metric essentially applies passive house standards, which are intended for residential buildings in dry conditions, to all types of buildings. In the proposed update of the DC construction code (which has been stuck in the mayoral review process for over two years), an updated version of Appendix Z is provided that no longer includes this metric.
We think this metric is very difficult to meet for a pool, because of the higher desired indoor temperature, but it is not impossible. Nevertheless, we recommend that the requirement be dropped for pools as long as the ZEPI metric (we explain this metric later on in this testimony) is maintained. The rationale is that as long as a reasonable requirement for overall energy efficiency is maintained that considers the special energy consumption of the pool as a building type (as the ZEPI does), we don't think that achallenging TEDI requirement is needed over and above the ZEPI.
If the ZEPI requirement were dropped, however, we do recommend a looser TEDI than the current Appendix Z requirement be included, and we provide some suggestions at the end of this letter.
- Cooling energy demand intensity (CEDI) : <= 6.4 kBTU/sq. ft. per year.
This metric is the cooling demand per year divided by the square footage of the building. It should not be hard to meet, since the pool indoor design temperature is higher than for typical residential buildings, and hence the cooling load is lower. Nevertheless, it is important to note this requirement is also eliminated in the pending updated Appendix Z. However, if the engineering team treats the energy needed to run the dehumidification equipment as contribution to cooling load (rather than treating it as energy for internal process loads akin to any other internal equipment) then this metric would be hard to meet and the CEDI requirement should be waived.
- Zero Energy Performance Index (ZEPI) <= 30
The zero energy performance index (ZEPI) is the ratio of energy performance of the rated building to the average energy consumption of a similar building at the turn of the millennium that is operated in a similar climate, for similar hours and under similar operating conditions.
Essentially, the ZEPI requirement is for the pool to use 30 percent of the energy of a comparable pool in the year 2000. If the proposed design of the pool includes heat pump dehumidification with the reclaimed energy used to heat the pool water, an air source heat pump (or a geothermal heat pump) for water and space heating, energy heat recovery for ventilation as well as reasonable levels of air sealing, and a reasonable quality of thermal envelope, the building should be able to meet this requirement. We believe that those measures are good value for money investments and do not add high costs when considering both upfront and operating costs.
This judgement that the ZEPI of 30 is achievable is supported by the evidence that the Congress Heights Recreation Center with pool proposed to the Green Building Advisory Council at its January 2025 meeting was able to achieve a ZEPI of 27.8, satisfying the minimum ZEPI of 30.
We conclude by emphasizing that natatoriums can be built to a net zero standard - all electric, highly efficient and utilizing on-site solar as best as the site allows. However, the specifics of the requirements in Appendix Z may need to be adjusted, particularly the maximum TEDI and CEDI requirements. Finally, we stress the importance of pools for the District’s objective to lower government utility bills. An Indoor pool not designed to a net zero standard typically has an EUI in the hundreds of kBTU/ft² per year—much higher than typical office or school buildings. Precisely because pools use a lot of energy, investing in energy efficient design and all electric construction makes these types of buildings important to get right. If we get them wrong, DC taxpayers are burdened with needlessly high energy bills and higher emissions for decades to come.