Estimate Your Potential Energy Savings with APR Control®
The APR Control® ROI Calculator is designed to help estimate the potential annual energy savings and payback opportunity that may be achieved by improving part-load system performance in DX air conditioning applications.
By enabling continuous compressor unloading and lower evaporator fan speeds, the APR Control often allows systems to operate at significantly reduced airflow — frequently 50% lower or more during reduced load conditions. Because fan energy decreases dramatically as speed is reduced, this can create meaningful energy-saving potential beyond compressor savings alone.
Our calculator uses conservative assumptions based on industry research, third-party testing, and typical operating conditions to provide a practical estimate of real-world performance.
Calculate Your Estimated Annual Savings & Payback
APR + VFD ROI Calculator
Estimate annual savings and simple payback for converting existing commercial DX equipment into a single-zone VAV-style solution using APR Control and a VFD.
Project inputs
Assumptions used in this version
Estimated results
Base case annual savings
Base case payback
Base case energy reduction
| Metric | Value | Comment |
|---|---|---|
| Baseline compressor energy | 0 kWh | Current constant-volume case |
| Baseline fan energy | 0 kWh | Current supply fan case |
| Annual compressor savings | 0 kWh | APR-driven low-load value |
| Annual fan savings | 0 kWh | VFD-driven value |
| Total annual savings | 0 kWh | Total kWh saved per year |
| Retrofit cost | $0 | Units × installed cost per unit |
| Scenario | Annual $ savings | Payback | Energy reduction |
|---|
Suggested talk track
Estimates are derived from standard assumptions and industry data and are intended for illustrative purposes only. Actual performance and savings will vary by application.
For a project-specific evaluation, the Rawal Devices, Inc. team is always available to help review your application.
Key Assumptions Behind the Model
To keep the estimate grounded and transparent, the calculator uses the following baseline assumptions:
- Fan power: 0.3 kW per ton, representing a typical standard-efficiency commercial unit rather than a high-efficiency system
- Compressor savings scenarios: 10% / 15% / 20%
Third-party testing has demonstrated approximately 16% actual compressor energy savings, so the base case is intentionally conservative - Fan savings scenarios: 40% / 50% / 60%
While the APR Control can often support greater fan turndown, actual savings may be limited by duct design, required minimum airflow, and application-specific control strategies - Electricity rates and annual operating hours: based on typical commercial operating conditions and utility rates commonly seen in the Mid-Atlantic region, particularly the Philadelphia market
Important Notes and Caveats
This calculator is intended as a planning and budgeting tool only.
Results shown are estimates, not guaranteed savings, and actual performance will vary based on equipment type, control sequence, occupancy patterns, airflow limitations, staging logic, and site conditions.
The current model is primarily based on single-stage unit operation. Multi-stage and unloading systems may experience different savings profiles depending on how often each stage operates. For example, second-stage compressor runtime may be substantially lower than full annual operating hours.
This model is intentionally focused on estimated real-world kW usage reduction, rather than relying solely on efficiency ratings such as SEER, IEER, or IPLV. While these ratings are useful benchmarks, they do not fully capture the actual part-load conditions the unit operates in for about 90% the time. This is exactly where the APR Control®, paired with an evaporator fan VFD, delivers value.
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Proven Energy Savings with Real Manufacturer Testing
See how independent manufacturer testing confirmed measurable part-load energy savings with the APR Control.
Traditional efficiency ratings often fail to reflect how HVAC systems actually perform in the field. See how manufacturer testing revealed a 16% reduction in first-stage compressor power consumption at part load with the APR Control installed. Explore the real data and results behind the performance claims.
