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Custom AHUs and Long-Term ROI

Lowest price wins the tender far too often. But in HVAC, the sticker price is only the start.

Less than 20 percent of a system’s lifetime cost comes from buying and installing it. The rest lies in the years of power use, servicing, and unplanned repairs that follow. According to the South African Council for Scientific and Industrial Research (CSIR), building-services equipment accounts for roughly 35 – 45 % of total operational energy use in modern commercial buildings — and HVAC alone can exceed 60 % of that share in high-load climates like Gauteng and KwaZulu-Natal. A cheaper packaged unit may tick boxes today but end up consuming more energy, needing more call-outs, and failing years sooner than a purpose-built design.

Custom AHU design

Total Cost of Ownership in HVAC

Total Cost of Ownership (TCO) looks at the full picture — every cost from installation to disposal:

  • Initial capital cost (IC): supply, delivery, installation
  • Energy cost (E): fans, coils, motors, and controls running daily
  • Maintenance and repairs (M + R): filters, bearings, belts, coils, sensors
  • Downtime losses (D): comfort or productivity lost when systems fail
  • Residual value (RV): any recoverable value at end of life

Energy and maintenance make up about 70 – 85 % of that total. Cutting either delivers compounding savings.

Why Lifecycle Thinking Delivers Better ROI

Lifecycle costing changes how projects are judged:

  • Efficiency outranks cheapness.
  • Reliability and access cut downtime.
  • Durability spreads capital over decades, not years.

In South Africa’s carbon-tax environment (Phase 2 implementation 2023 – 2026), efficient HVAC design directly affects an organisation’s greenhouse-gas liability. Energy-intensive sites can reclaim up to 95 % of their taxable emissions through efficiency offsets, turning energy savings into measurable financial benefit. A system built for its exact duty point, with accessible components and service routes, keeps paying for itself year after year. Frameworks such as Eurovent 6/19 and CIBSE TM54 show that facilities using lifecycle analysis achieve lower total cost of ownership even with higher upfront budgets.

What Makes a Custom AHU Different

Built for Purpose

Standard AHUs suit “most.” Custom units suit yours. That difference drives everything from energy use to service life. Local manufacturing capability has advanced sharply. South African fabricators now produce double-skin, thermally broken casings to Eurovent standards, shortening lead times that once forced imports from abroad. Each system is engineered for the building’s actual air volume, pressure, and environment, reducing losses and wear.

Design Flexibility and Energy Efficiency

Performance takes priority over catalogue convenience:

  • Coils sized for real load profiles
  • EC or plug fans with direct drives
  • Casing geometry shaped for smooth airflow
  • Energy-recovery wheels or coils reclaiming heat
  • Controls that balance load and fan speed automatically

These refinements typically cut 15 – 25 % off annual energy use.

Materials and Construction Quality

Higher-grade materials equal longer service life:

  • Reinforced frames and 50 mm insulated panels
  • Epoxy or powder-coat finishes for coastal and industrial air
  • Thermal breaks that prevent condensation

In coastal regions such as Durban and Port Elizabeth, corrosion is the main cause of premature HVAC failure. Using stainless-steel drain pans and marine-grade coatings extends service life by five to eight years.

Mechanisms of Lifecycle Value

Energy Efficiency and Operational Savings

Average Eskom tariff escalation has exceeded 9 % per year since 2015. During the same period, building owners who invested in high-efficiency fans and energy-recovery AHUs reported 20 – 30 % lower operating expenses despite rising energy costs (SANEDI Energy Use in Buildings Survey 2024). Lower fan energy, smarter controls, and recovered heat compound into steady savings.

Reduced Maintenance and Downtime

Custom layouts make access simple. Technicians can inspect, clean, and replace components without dismantling half the system. Under SANS 1850 and ASHRAE 62.1, healthcare facilities must verify airflow and filtration quarterly. Units that can be checked safely and quickly lower labour cost and infection risk.

Extended Lifespan and Asset Value

A solid custom AHU runs 20 – 25 years; standard units often fail by 15. That extra decade defers not only the replacement spend but also the embodied-carbon footprint of manufacturing — roughly 2.5 t CO₂e per medium-sized AHU (2024 LCA studies, Building and Construction Council SA).

How to Quantify ROI for a Custom AHU

South African Cost Context

Locally, energy usually accounts for 50 – 60 % of AHU lifecycle cost, maintenance about 20 %, and capital amortisation the rest. With average commercial electricity now above R 2.60 / kWh (2025), even a 10 % reduction in energy use translates into substantial long-term savings. Lifecycle analysis turns those efficiencies into numbers that finance teams can work with.

Sample ROI Scenario

For a 25 000 m² office park in Sandton running twelve 50 kW AHUs, switching from standard to custom designs with EC fans and energy-recovery coils reduced total HVAC energy by 210 MWh a year. At R 2.60 / kWh, that’s roughly R 546 000 saved annually — covering the additional R 1.8 million capex in 3.3 years. Even modest efficiency gains can shift ROI dramatically.

Real-World Examples and Case Studies

Food-Processing Plant, Western Cape

A 2024 retrofit for a dairy processor in Paarl introduced custom hygienic AHUs with integrated UV sterilisation and variable-speed drives. Energy bills fell 22 %, downtime incidents dropped 40 %, and the system passed ISO 22000 clean-air audits on first inspection.

Industrial and Pharma Applications

Pharmaceutical facilities demand absolute reliability. Custom modular AHUs with redundant fans, dual cooling coils, and HEPA filtration keep conditions stable where catalogue units fail. A Johannesburg pharma plant reported zero contamination events over 24 months and full payback within five years after replacing standard systems with GMP-compliant custom units.

Data Centres and ESG Pressure

Globally, data centres use around 3 % of total electricity. In South Africa, hyperscale sites in Cape Town and Johannesburg face steep power and cooling costs. Custom AHUs using indirect-evaporative cooling and EC fans have achieved PUE values below 1.4 — well ahead of the regional average of 1.8.

Institutional Use Case

Universities, hospitals, and public facilities often balance strict budgets with long operational horizons. By modelling lifecycle value instead of upfront cost, these institutions align capital planning with sustainability goals. Several campuses across Gauteng and the Western Cape now include lifecycle-cost clauses in HVAC tenders, ensuring procurement focuses on long-term value, not short-term savings.

Practical Guidance

Engage Early in Design

Bring the AHU manufacturer or mechanical engineer into the concept stage. It prevents redesigns later and ensures the plantroom layout, duct routing, and service access align from the start.

Specify Performance, Not Just Dimensions

Define what the system must achieve — not what box to buy:

  • Airflow, pressure, temperature, humidity targets
  • Efficiency, noise, and maintainability limits
  • Access clearances and drainage details

Performance-led briefs give suppliers the freedom to engineer optimal solutions.

Evaluate Lifecycle Cost in Tenders

Request a full lifecycle breakdown — energy, maintenance, and replacement — and weight those factors higher than initial price. Public-sector infrastructure projects under the Infrastructure Fund (SA National Treasury, 2024) now require lifecycle costing for mechanical services, allocating 60 % of tender weighting to operational and maintenance cost over 20 years.

Plan for Maintenance and Upgrades

Choose modular designs, standardised filters and drives, and digital monitoring that predicts faults before they stop the system. Long-term service contracts preserve uptime and warranty coverage.

Validate Before Handover

Commissioning should verify airflow, temperature, and leakage performance, as well as integration with the BMS. Proper documentation at handover prevents future troubleshooting costs.

Air Options – Custom AHUs for Long-Term ROI

With South Africa’s net-zero 2050 target approaching, HVAC efficiency is one of the fastest, most cost-effective ways to cut carbon in the built environment (Department of Forestry, Fisheries and the Environment, GHG Mitigation Report 2023). Custom AHUs aren’t a luxury. They’re an investment that pays itself back through lower energy use, reduced downtime, and decades of dependable service. Air Options designs and manufactures custom-engineered air-handling units for commercial, industrial, and specialised environments. Our engineering team partners with consultants and building owners to balance performance, reliability, and lifecycle value from design through long-term operation. Contact us to discuss your facility’s next HVAC investment or request a lifecycle-cost analysis. 

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