Preventive maintenance: TCO management and operational continuity
Maintenance TCO: four criteria to balance preventive and corrective by age
On a large commercial property portfolio, an unmanaged drift in the maintenance line can wipe out several million euros of asset value. Kytom regularly observes this slippage during its audits, and it is almost always tied to the same reflex: applying a standard preventive/corrective ratio to an ageing building that requires a rebalanced approach. We take over the management in 12 weeks, from the initial audit to the rollout of the optimised plan, based on three parameters (criticality, age, usage intensity) rather than the manufacturer’s calendar. On the sites we manage under preventive maintenance, the availability of critical equipment improves significantly compared with scopes managed under purely corrective maintenance before our intervention. The regulatory framework heightens the stakes: the tertiary decree imposes a trajectory for reducing final energy consumption that rests directly on the performance of maintained equipment. Three levers structure our approach: TCO arbitration calibrated to the age of the building fabric, hunting down recurring budget drifts, and a 4-step method integrated into design and build.
The framework
TCO arbitration rests on four structuring criteria, which carry different weights depending on the building’s age and the criticality of the equipment.
- Operational criticality: the impact of a shutdown on activity (lift, BMS, server room versus sanitary mechanical ventilation).
- Optimal intervention frequency: calibrated to the manufacturer’s reliability curve and actual operating hours.
- Preventive cost / corrective cost ratio: preventive maintenance is profitable when its annualised cost remains clearly below the corrective cost avoided, including downtime charges.
- Manufacturer warranty impact: preventive maintenance that does not comply with manufacturer recommendations risks the loss of warranty on HVAC equipment, as our supplier feedback regularly confirms.
In practice at Kytom, the canonical 70/30 ratio used in most multi-technical contracts over-maintains buildings more than 10 years old. Beyond that age, several equipment families such as end-of-life HVAC or obsolete BMS benefit more from planned corrective maintenance coupled with a renewal plan than from systematic preventive maintenance whose marginal return collapses.
As an indication, industry practices suggest a preventive/corrective split that evolves with the building’s age: predominantly preventive on recent buildings aged 0 to 5 years, with a gradual rebalancing towards corrective maintenance as equipment ages. The costs of routine maintenance, excluding major upkeep and renewal, generally fall within a range that widens as the portfolio matures.
Your gains
CFO and Asset Manager: three drifts that send the maintenance budget off course
For an Asset Manager overseeing several tens of thousands of square metres, a drift on the maintenance line represents significant NOI erosion each year, which translates into asset value loss at the prevailing capitalisation rate. Kytom audits bring out three systematic drifts, which compound in the absence of centralised management.
- Standardising frequencies on the manufacturer’s calendar. The same cycles apply to all equipment, with no weighting for actual usage. A commercial mechanical ventilation unit running 50 hours a week does not require the same frequency as a process air handling unit running 24/7.
- Lack of traceability. Without a structured history of intervention findings, the progressive optimisation of schedules remains impossible. Regulations also require an up-to-date safety register for equipment subject to obligations (lifts, smoke extraction, electrical systems).
- Preventive/corrective silos. Interventions are not pooled by zone, which multiplies mobilisation costs when each trade travels separately.
Kytom consolidates the three axes: frequencies indexed to meters and sensors, each finding documented to revise the frequency, and interventions grouped by technical lot or geography. On scopes rationalised in this way, we observe an appreciable reduction in the overall maintenance cost, at equivalent or higher availability. For your CFO, the gain translates into recurring OPEX, a direct margin on the tertiary decree trajectory since better-maintained equipment consumes less.
When this approach is not the right one. Centralised rationalisation loses its value below 3,000 m² in operation or for a portfolio with few critical equipment items: the structuring cost (audit, CMMS, management) then exceeds the expected gain over five years. A fixed-price multi-technical contract with quarterly reporting remains more profitable. Likewise, a single-tenant site under a short-term derogatory lease does not justify full deployment: the return on investment occurs beyond the end of the lease.
Method
- Technical audit and classification by criticality
Exhaustive inventory of the equipment portfolio, classification across 3 levels of operational criticality and establishment of the reference state. Kytom met régulièrement en évidence des écarts entre les recommandations constructeur et l’usage réel sur une part significative du parc audité. Duration: 3 to 4 weeks depending on site size. - Optimised planning on 3 parameters
Definition of intervention frequencies by cross-referencing criticality, equipment age and usage intensity measured by hour meters. Kytom replaces the uniform manufacturer calendar with variable cycles: an air handling unit at 2,200h/year is not serviced like one at 6,500h/year. Deliverable: a costed preventive plan calibrated over 12 months. - Coordinated deployment by lot
Grouping of interventions by zone and by technical lot to reduce mobilisation costs by 20 to 30% (14 sites 2023). Implementation of the CMMS and training of on-site teams. Duration: 4 to 6 weeks to switch over from the old plan to the new one. - Monthly KPI management
Tracking of 3 main indicators: critical equipment availability (target 98.5%), cost in €/m²/year, and user satisfaction rated out of 5. Quarterly review with the CFO or Asset Manager to adjust frequencies based on documented intervention findings.
Frequently asked questions
What preventive/corrective ratio should I target based on the building’s age?
As an indication, a recent building under 5 years old can target a ratio clearly weighted towards preventive maintenance, while a building over 10 years old requires a larger corrective share, to be calibrated according to the actual condition of the equipment. The standard ratio applied uniformly over-maintains older buildings and costs more without any availability gain. The arbitration must also take into account operational criticality and actual usage intensity, measured by hour meters rather than estimated on the manufacturer’s calendar.
How does Kytom secure availability on critical equipment?
Through the 4-step method deployed over 12 weeks: an audit with classification by criticality across three levels, planning calibrated on hour meters rather than the manufacturer’s calendar, grouped deployment by lot to reduce mobilisation costs, and monthly management on three KPIs. design and build integration also makes it possible to avoid a significant share of corrective interventions over the first years of operation.
