Tower Earns UL Verified Healthy Building Mark for Indoor Air
Whether it’s wildfire smoke, seasonal allergens, or everyday air quality concerns, the importance of healthy indoor environments has never been clearer. The Tower Companies has long believed that building performance extends beyond energy efficiency to include the health and well-being of the people inside.
That commitment is reinforced by once again earning the UL Verified Healthy Building Mark for Indoor Air across Tower’s managed portfolio, a distinction we have maintained annually since 2021. This third-party verification confirms that Tower’s buildings are designed and operated to support healthier indoor environments through rigorous standards for ventilation, filtration, HVAC performance, and indoor air quality. For office clients and multifamily residents alike, it provides added confidence that our spaces are designed to support comfort, well-being, and day-to-day performance.
A Portfolio-Wide Commitment to Healthy Buildings
While many buildings treat healthy building strategies as one-off projects or minimum compliance efforts, The Tower Companies embeds indoor air quality, sustainability, and operational performance into its portfolio-wide standard of care. Through third-party verification, air quality testing and inspections twice a year, and an annual recertification process, Tower demonstrates that healthier indoor environments are central to how its buildings are managed and how long-term value is created for occupants, clients, and ownership.
The Verified Healthy Building Mark for Indoor Air applies across a diverse portfolio of office and residential properties in Washington, DC, and Maryland, including:
The Millennium Building
1828 L Street NW
1707 L Street Nw
2000 Tower Oaks Blvd
The Tower Building
BLair Office Building
The Pearl at The Blairs District
Blair East
Blair Plaza
Blair House
Blair Towns
By pursuing verification across the portfolio, Tower shows that healthier indoor environments are not one-off achievements, but part of how we operate every day.
What the UL Verified Healthy Building Mark Means
The UL Verified Healthy Building Mark is a science-based, independent review of indoor environmental quality. For the Indoor Air designation, UL evaluates building operations, HVAC performance, ventilation, filtration, and indoor air quality practices to confirm that buildings meet rigorous standards and have plans in place for continual improvement.
Focus on Indoor Air Quality
Indoor air quality is one of the clearest ways a building affects occupant experience. This verification confirms that Tower’s buildings are supported by practices that help deliver cleaner, well-managed indoor environments—an important differentiator for employers focused on workplace quality and for residents seeking healthier homes.
That translates into tangible value for occupants:
- • Healthier everyday environments: Building systems and air quality practices are reviewed to support comfort and well-being.
- • Greater confidence: Independent verification gives office clients and residents added assurance that performance claims are backed by outside review.
- • Ongoing performance: The program includes annual assessments and mid-year surveillance to help ensure standards are maintained over time.
What We Test For
As part of the annual indoor environmental quality inspections, UL Solutions evaluates a range of contaminants and environmental conditions tied to occupant health, comfort, and HVAC performance. The thresholds below must be achieved in order to earn certification.
| Parameter | UL / Referenced Threshold |
| Particulate Matter (PM) 2.5 | 15 µg/m3 |
| Carbon dioxide (CO2) | Outdoor level + 700 ppm |
| Carbon monoxide (CO) | 3.5 ppm |
| Formaldehyde | 0.08 ppm |
| Total volatile organic compounds (TVOCs) | 500 µg/m3 (approximately 0.3 ppm) |
| Sulfur dioxide (SO2) | 0.25 ppm |
| Nitrogen dioxide (NO2) | 0.20 ppm |
| Ozone (O3) | 0.05 ppm |
| Relative humidity | 65% upper limit |
| Temperature | Approximately 68–75°F in winter; 73–79°F in summer |
In every annual inspection, these parameters are checked throughout our buildings, and full recertification under the UL Verified Healthy Building Mark for Indoor Air can only be achieved when the building’s performance complies with these guidelines
Aligning Health, Sustainability, and Performance
The UL Verified Healthy Building Mark complements Tower’s broader sustainability strategy, which includes LEED, ENERGY STAR, Fitwel, and other high-performance building certifications. Together, these efforts reflect a more complete view of building performance—one that values both environmental performance and occupant well-being.
In a market where health claims are common, independent verification matters. The UL mark helps distinguish Tower’s portfolio by providing credible, third-party confirmation of healthy indoor air practices that support leasing, resident confidence, and long-term asset value.
A Commitment That Continues
The UL Verified Healthy Building Mark is not a one-time achievement. This certification is renewed annually through ongoing assessments and surveillance, reinforcing continuous performance rather than a one time achievement., our portfolio will continue to undergo regular assessments to help ensure these standards are maintained.
As expectations for healthier buildings continue to rise, Tower remains focused on delivering spaces that combine sustainability, operational excellence, and a better everyday experience for the people who use them.