Energy efficiency upgrades represent far more than sustainability measures; they’re among the few capital projects that can simultaneously reduce operating costs, help satisfy tightening energy-code requirements, and potentially maintain resident comfort, encouraging lease renewals.
This article explores the upgrades, ranging from component replacements to building envelope enhancements, that are most likely to produce measurable gains in performance, reliability, and energy efficiency.
Strategic System Upgrades to Prioritize
Here’s where to begin when planning upgrades that deliver measurable improvements in energy efficiency, system control, and long-term performance.
1. High-Efficiency Condensing Boilers
Condensing boilers reclaim latent heat from water vapor in the exhaust, boosting steady-state efficiency from about 80% in conventional boilers to a range of approximately 86% to 98%, which represents roughly a 10-18% improvement in efficiency over standard units.
Stainless-steel venting and low-temperature return water requirements are to be expected, so verification that distribution piping and pumps can handle cooler flows before installation is essential. When paired with outdoor-reset controls, these boilers may trim shoulder-season cycling and help extend equipment life.
2. Variable Refrigerant Flow (VRF) Systems
VRF technology moves refrigerant directly to indoor fan-coil units, modulating compressor speed so each apartment (or even each room) receives only the heating or cooling needed. The result can be whisper-quiet comfort and improved seasonal efficiency compared to constant-volume split systems.
3. Heat Pumps and Electrification Retrofits
Swapping gas-fired furnaces or boilers for high-performance heat pumps can address both energy costs and decarbonization. Modern air-source units often maintain capacity in freezing weather, while water-source models may conserve energy by sharing heat among apartments.
Annual energy usage can be reduced by 15% to 17% when replacing gas-fired equipment with heat pumps during retrofits in commercial buildings.
4. Energy Recovery Ventilation (ERV) Systems
An ERV transfers both heat and moisture between outgoing stale air and incoming fresh air, and reclaims 70% to 80% of the thermal energy from exhaust air. High-occupancy multifamily buildings that retrofit ERVs alongside tighter envelopes and smart thermostats can potentially see ventilation energy savings.
Because ERVs also help manage humidity, they may also reduce mold risk and tenant complaints. Tying the unit into existing rooftop make-up air curbs or mounting compact, unitized ERVs in corridors can be effective; ensuring that exhaust and intake paths are well separated can help prevent cross-contamination.
5. Smart Building Controls and Automation (BAS)
Networked sensors, cloud analytics, and machine-learning algorithms now fine-tune operation in real time. By aligning airflow, temperature setpoints, and equipment staging with actual occupancy, smart controls can help drive energy savings by as much as 8%. Remote dashboards, predictive maintenance alerts, and automated fault diagnostics may detect issues before residents notice them.
Verifying that legacy equipment speaks common protocols (BACnet, Modbus) or budgeting for gateway hardware (and protecting the new data stream with cybersecurity best practices) can help ensure optimal performance.
6. Variable Frequency Drives (VFDs)
Fans and pumps rarely need to run at full capacity. Installing VFDs lets motors ramp up or down smoothly, matching flow to real-time demand and potentially reducing both kilowatt-hours and wear. Soft-start motor control may also reduce mechanical stress, potentially extending bearing and belt life.
To get the most from your HVAC upgrade, combine variable-speed drives with pressure sensors and recalibrate the controls. This simple adjustment may prevent wasted energy caused by older, fixed-speed settings.
7. Demand-Controlled Ventilation (DCV)
DCV uses CO₂ or occupancy sensors to modulate outside-air rates, potentially preventing the energy penalty of over-ventilation in gyms, lounges, and other intermittently used common areas. When integrated with a BAS, airflow may drop automatically when spaces empty out, yet spike quickly to keep air fresh during events. Multifamily studies track significant load reductions when DCV replaces fixed damper positions, especially in warm, humid climates where conditioning outside air is costly.
Checking ventilation settings against building code limits and keeping sensors calibrated helps maintain consistent airflow and reliable system performance.
8. High-Performance Air Filtration and Duct Sealing
Leaky ducts can waste 20–30% of conditioned air, often dumping it into wall or ceiling cavities. Aerosolized sealing or manual mastic work can help restore full airflow to living spaces, potentially allowing for downsizing equipment at replacement time. Upgrading to MERV-13 (or higher) filters may further improve indoor air quality without throttling fan performance, provided static-pressure allowances are verified.
Because both tasks align with routine maintenance cycles, they can be low-disruption improvements that may accumulate savings and increase tenant satisfaction.
9. Thermal Energy Storage or Load Shifting Systems
Chilled- or hot-water storage tanks charge at night when electricity rates dip, then discharge during expensive peak hours, potentially flattening demand charges and improving efficiency. Demand response and load management programs—common in time-of-use (TOU) markets—can reduce peak demand, depending on the geographic area and implementation factors.
Integration is typically simplest in properties already running central chillers or heat-pump loops; adequate mechanical-room footprint and control algorithms that coordinate charging with weather forecasts and tariff schedules are necessary. Over time, storage may also provide resilience by helping maintain comfort during short grid outages.
10. Building Envelope and Insulation Enhancements
Envelope improvements—adding roof insulation, upgrading single-pane glazing, and sealing façade cracks—can deliver measurable whole-building savings while lowering peak loads. The EPA ENERGY STAR program estimates that air sealing plus insulation saves around 15% on heating and cooling (about 11% of total energy), on average.
The DOE Energy Saver guidance notes that cutting drafts (air leaks) alone can reduce energy use by around 10-20%. For windows, recent LBNL analysis of nationwide commercial upgrades finds 4-6% typical site-energy savings, and up to 26% in higher-potential buildings, underscoring the impact of improved glazing on HVAC loads.
What are the Benefits of HVAC Upgrades on a Multi-Unit Property?
When multi-family buildings receive system upgrades, the benefits extend far beyond energy conservation.
- Reduced Operating Costs: High-efficiency systems can lower utility expenses and maintenance requirements, potentially improving net operating income.
- Regulatory Compliance: Proactive upgrades can help properties meet increasingly stringent energy codes and carbon reduction requirements.
- Extended Equipment Lifespan: Modern systems with smart controls and variable-speed components may experience less wear and operate more efficiently.
- Improved Tenant Comfort: Better temperature control, reduced noise, and enhanced air quality can lead to higher resident satisfaction.
- Lower Vacancy Rates: Comfortable living environments with consistent temperatures and proper ventilation may encourage lease renewals.
- Increased Property Value: Energy-efficient buildings often command higher valuations and attract environmentally conscious residents and investors.
- Enhanced ESG Performance: Upgraded mechanical systems can help improve sustainability metrics important to investors and stakeholders.
- Reduced Carbon Footprint: Lower energy consumption translates to decreased greenhouse gas emissions, supporting organizational sustainability goals.
How to Plan an HVAC Upgrade for a Multi-Unit Property
A disciplined plan with the following five steps can help minimize surprises and cost overruns.
- Conduct Energy Audit: Professional testing identifies hidden energy losses and establishes a baseline for improvement opportunities.
- Model Financial Scenarios: Calculate potential ROI using audit data to compare different upgrade options against long-term utility costs and available incentives.
- Prioritize Strategic Upgrades: Select improvements that balance maximum energy savings with minimal tenant disruption.
- Coordinate Engineering Early: Involve mechanical, electrical, and plumbing engineers from the beginning to prevent redesigns and ensure code compliance.
- Verify Performance: Implement monitoring systems to document savings, support compliance reporting, and enable predictive maintenance.
With this structured approach, aging systems can be transformed into efficient assets that may reduce operating costs while helping maintain resident comfort.
Engineering Energy Efficiency Across Complex Buildings with Rimkus
Rimkus engineers can recommend upgrades and can help prove how upgrades might work before installation. Energy audits can identify where buildings waste power, and targeted retrofits can potentially reduce energy use in multifamily properties while helping improve resident comfort and lower utility costs.
The life cycle process, Audit → Design → Implementation Oversight → Verification, aligns with ASHRAE and LEED best practices. Every recommendation is grounded in data and modeled for real-world performance before construction begins. Field specialists monitor workmanship and commissioning to help confirm that high-efficiency equipment, smart controls, and ventilation upgrades perform as expected.
With more than 40 years of consulting experience, a network of 900 experts across 100 offices, and deep mechanical and energy expertise, Rimkus combines forensic insight with forward-looking design to help deliver measurable savings and regulatory compliance.
Contact us to schedule an energy audit or discuss how targeted HVAC upgrades can help reduce operating costs, improve comfort, and align properties with evolving efficiency standards.
This article aims to offer insights into the prevailing industry practices. Nonetheless, it should not be construed as legal or professional advice in any form.