Mostadam, LEED and Window Film: Where Retrofit Film Actually Contributes to Saudi Green-Building Energy Credits

What Mostadam Is — and Why It Matters Most to Owners of Existing Buildings

Mostadam is Saudi Arabia's national green building rating system, developed under the Ministry of Municipal and Rural Affairs & Housing as a home-grown framework rather than an imported system applied unchanged to a Gulf climate. The logic is straightforward: sustainability criteria designed for a temperate climate do not necessarily drive the right decisions in a city like Jeddah, where cooling consumes the largest share of a building's electricity almost year-round, and where humidity, dust and solar radiation impose priorities very different from those of a building in northern Europe.

Mostadam runs on parallel tracks: one for residential buildings, one for commercial buildings, and one for communities. Each track then splits into two fundamental versions: Design + Construction (D+C), applied to new projects from the first drawing, and Operations + Existing (O+E), applied to a building that is already running and which measures real performance rather than paper performance. Certification levels are tiered: Green, then Bronze, Silver, Gold, and Diamond at the top.

The system distributes its requirements across categories including Energy, Water, Site Sustainability, Health & Comfort, Materials & Waste, and Policies, Management & Maintenance — alongside additional, largely optional categories such as Transport & Connectivity, Region & Culture, and Education & Innovation.

What matters directly to a building owner is the operational version. It is the realistic gateway for thousands of existing buildings in Jeddah, Riyadh and Dammam that were built before the current wave of energy-efficiency requirements. These buildings cannot change their orientation or their glazing ratio, but they can improve what they already own — and that is precisely where upgrading the performance of existing glass becomes a genuine negotiating asset.

Mostadam and LEED: Two Different Systems, One Shared Logic on Energy

Many owners ask: "Should we go for Mostadam or LEED?" The professional answer is that this is usually not an exclusive choice. LEED is a US-origin system developed by USGBC, with certification administered by GBCI, and is recognised globally; it has a dedicated path for existing buildings (O+M). With LEED v5 released it is the newest version, while v4 and v4.1 remain open for registration until 30 June 2027, and certification under them stays possible until 30 June 2033 per USGBC’s published dates — dates that do get updated, so check the deadlines page before committing. Confirm which version your project is registered under before any calculation. Mostadam is a Saudi national system speaking to the local regulatory environment and tied to municipal requirements and authorities. Many major projects in the Kingdom pursue both: LEED because international tenants and investors read it, Mostadam because it is the local language of compliance and government recognition.

The critical point for an engineer is that the two systems converge exactly where it matters to us: energy performance. Both — in their existing-building paths — measure performance rather than intent, and both fundamentally rely on comparing the proposed building's consumption against a reference baseline, whether through full energy modelling or through measured actual consumption benchmarked against peers. In both routes, no envelope measure is evaluated in isolation from the rest of the building; it is judged by its effect on total annual consumption.

This means that installing film on a building with a wide glazed façade exposed to the south and west will read very differently in the model than installing it on a building with small, architecturally shaded openings. It also means the consultant will not accept the sentence "film saves energy." They will ask for the glass performance figures before and after, feed them into the simulation software, and read the output. The differing credit names between versions do not change this underlying logic.

Saudi Building Code SBC 601/602: The Mandatory Floor Beneath Any Rating

Before discussing any voluntary certification, there is a mandatory floor: the Saudi Building Code for energy conservation. SBC 601 sets minimum energy-efficiency requirements for buildings generally, excluding low-rise residential buildings, while SBC 602 addresses low-rise residential buildings and sets requirements for exterior envelope insulation, window and door U-factors and Solar Heat Gain Coefficient (SHGC) values, alongside duct insulation, lighting systems and electrical power system efficiency.

A professionally important point: the code specifies that U-factors for fenestration products are determined in accordance with NFRC 100, and that SHGC for glazed fenestration is determined in accordance with NFRC 200, by an accredited independent laboratory. This is not a formality — it is precisely the reference framework against which the spec sheet of the film you propose will be judged. A film without performance data derived through a recognised methodology is, from the consultant's point of view, a product with no number to enter into the model.

The relationship between code and certification is best understood this way: the code is the minimum you may not fall below, and rating systems like Mostadam and LEED are what rises above that minimum and gets rewarded. Improving the performance of existing glass does not serve the certificate alone; it may be the only realistic route to lift an older building toward envelope performance levels close to the spirit of modern code requirements, without demolition or façade replacement. We covered this dimension in depth in our SBC 601/602 glass compliance guide.

Where Film Actually Enters: SHGC, U-Value and Spectral Selectivity

Window film modifies three numbers every envelope designer knows, and each of them has a different door into a rating system.

First: Solar Heat Gain Coefficient (SHGC) — the fraction of solar energy that passes through the glazing into the space, either directly or by re-radiation. The lower the SHGC, the lower the solar thermal load on the cooling system. This is film's most important entry point in Jeddah's climate, because in buildings with glazed façades solar gain through glass represents a substantial share of total cooling load.

Second: the U-factor — the overall rate of non-solar heat transfer through the assembly, combining conduction, convection and radiation. Low-emissivity (Low-E) films designed for interior application improve this figure because they cut the radiative share of that exchange between the glass surface and the interior space. The effect here is quieter than the SHGC effect but real, and shows up especially on single glazing.

Third: Visible Light Transmission (VLT), and its ratio to solar gain. Spectrally selective film — such as nano-ceramic and multi-layer products — is engineered to pass the visible spectrum while blocking the near-infrared band of sunlight that carries most of the solar heat. That means the space stays daylit and daylighting gains are not thrown away, which is the decisive distinction between it and older metallised reflective film that buys heat rejection at the price of darkness.

In our field thermal study in Jeddah (2024-2026), covering 530 vehicles with a FLIR T530 camera under ISO 13837:2021, nano-ceramic films recorded 96-97% infrared and 99% ultraviolet rejection. The study was conducted on vehicle glass rather than building glass, but it demonstrates the same spectral-selectivity principle that architectural film is built on.

From Cooling-Load Reduction to Energy Points: How Film Is Counted Inside the Model

This is the most important paragraph in the article, and we write it with a candour that may not please anyone who oversells film: **film does not award automatic points**. Not in Mostadam, not in LEED. What actually happens is this.

One clarification before the mechanics: the energy model described here is how a measure earns credit on the design-and-construction paths (Mostadam D+C, LEED BD+C). On the existing-building paths this article is aimed at — Mostadam O+E and LEED O+M — the energy score is driven mainly by actual metered consumption benchmarked against a baseline period or a peer data set, and the model is used to predict and prioritise the measure rather than to earn the credit on its own. That is why the meter readings in step 8 of the roadmap are not an optional extra.

The energy engineer builds a computational model of the building: its geometry, orientation, glazing ratios, the properties of every glazing assembly, occupancy schedules, and the performance of HVAC and lighting systems. The model is then run at least twice: once against the reference baseline, and once against the proposed case including the proposed measures — film among them. The difference in annual consumption between the two runs is what translates into credit within the energy performance category.

From this comes the second professional truth: film's impact is variable, not fixed. A Jeddah building with a wide west-facing glazed façade in clear single glazing will show a large delta in the model. A building with limited openings, already fitted with double Low-E glazing and good architectural shading, will show a far smaller one. Same product, two entirely different outcomes.

That is why anyone promising you a specific point figure before the model is run is speaking outside the methodology. The number depends on the rating version adopted by your project, on the simulation software used, and on whether the model is calibrated against actual metered consumption.

The figure we stand behind, from our building glass insulation projects, is an HVAC energy saving in the region of 35-40% in suitable applications. That is a whole-package insulation figure, not a number film alone is guaranteed to deliver, and it is an input for discussion and verification inside the model — not a promise of points.

Thermal Comfort and Glare: Film's Second Door In

Energy is not the only entry point. Mostadam's Health & Comfort category, and the corresponding Indoor Environmental Quality credits in LEED, deal with the occupant's own experience — an area where glazing has a direct, tangible effect.

The classic problem in glazed offices in Jeddah is familiar to every facility manager: the employee sitting by the window complains of heat while a colleague deeper in the floorplate complains of cold. The cause is not a fault in the HVAC — it is that the hot glass surface radiates heat toward the occupant and raises the mean radiant temperature around them. The practical consequence: the thermostat is dropped for an entire floor to satisfy one row of desks, energy is wasted twice over, and the complaints never stop.

Reducing solar gain at the glass surface treats this at source: the thermal gradient between perimeter and core narrows, and a sensible thermostat setpoint becomes acceptable to everyone. That is exactly what thermal comfort credits measure.

The second dimension is glare. Direct glare on screens is what drives staff to keep blinds permanently closed — and once the blinds are down the window is effectively sealed, daylighting gains are extinguished entirely, and artificial lighting runs all day. Spectrally selective film reduces thermal intensity and glare while retaining a high proportion of visible light, so the blinds stay up. In this way the energy measure protects the daylighting credit instead of conflicting with it — a point consultants value highly, because most shading alternatives win in one category and lose in another.

Why Film Instead of Glazing Replacement in Existing Buildings

Let us be fair to the alternatives: replacing glazing with double Low-E units is theoretically the higher-performing solution. We do not dispute that. But the decision for an existing building is not made on a performance sheet alone — it is made against four combined constraints.

The first is capital: re-glazing an office tower's façade sits in an entirely different investment class from upgrading the existing glass, and usually consumes the whole improvement budget for years ahead.

The second is operational: replacement means scaffolding or suspended platforms, evacuation of interior zones, work on frames and fixings, and weeks or months of disruption. In a leased building that is lost revenue and strained tenant relationships, not mere inconvenience. Film is installed from inside the building, floor by floor, usually outside working hours, and the space returns to use the same day.

The third is regulatory and structural: changing the glazing make-up can require review of façade and frame loading and technical approvals, particularly in curtain-wall buildings.

The fourth is embodied carbon: sending sound glass to waste and manufacturing a replacement carries an environmental cost that partly contradicts the very goal of the certification. Getting more out of the existing asset instead of replacing it aligns with the philosophy of existing-building rating systems.

The professional bottom line: film does not beat double Low-E glazing on absolute performance. But in many existing buildings it is the only measure that can actually be executed this year, on an operating budget, without shutting the building down — and an executed measure always beats a deferred one.

The Technical File Your Sustainability Consultant Will Ask For

This section is what separates a project where film is counted from one where it is rejected. The consultant does not evaluate the film; they evaluate the documentation. Prepare the following before you sit down with them.

**First: the manufacturer's Technical Data Sheet**, specified by the exact product code rather than the family name. It must contain SHGC, Visible Light Transmission (VLT), U-value, and infrared and ultraviolet rejection figures — and those values must be stated for a glazing make-up matching your building's actual glass. A film's value on 6 mm clear single glazing differs from its value on tinted double glazing. The values must be derived under a recognised methodology (NFRC 100 for U-factor, NFRC 200 for SHGC).

**Second: the as-built glazing schedule** — glass type, thickness and tint per façade, with areas. Without it the "before" values cannot be established at all.

**Third: installer certification** from the manufacturer, because documented performance presumes installation to the manufacturer's instructions.

**Fourth: the original written warranty** issued by the manufacturer in the project's name, with its duration and its coverage and exclusion clauses.

**Fifth: post-installation documentation** — photographs, product batch numbers, ideally a comparative before/after thermal survey of the glass surfaces, and metered consumption readings for operational verification.

The practical advice: bring the consultant into the decision before purchase, not after. Selecting a film with excellent specifications but no auditable documentation means you have paid for the measure and lost its recognition.

The Mistakes That Kill Film's Contribution — and How to Avoid Them

We have seen projects buy a good film and lose recognition for it. The reasons repeat.

**Mistake one: ignoring film-to-glass compatibility.** This is not an administrative slip but a genuine technical hazard. A high-absorption film on annealed, tinted, thick, or insulated-unit glass can raise thermal stress in the pane to the point of cracking. Manufacturers publish compatibility charts specifying which film is permitted on which glazing make-up. Overriding those charts voids the warranty and creates a safety risk.

**Mistake two: selecting film on a "darker is better" basis.** A very dark film does reduce solar gain, yes — but it extinguishes daylight and forces artificial lighting to run through the day, so you win on the envelope and lose on lighting and visual comfort. The correct criterion is the highest light gain per unit of heat rejected, not the highest opacity.

**Mistake three: a product with no documented supply chain.** Film with no manufacturer name, no product code and no project-named warranty cannot be entered into an accredited energy model, however good it looks on day one.

**Mistake four: uncertified installation.** Bubbles, edge lift, contamination under the layer — all of these lose the declared performance and void the warranty.

**Mistake five: executing the measure without modelling it.** If the film is not entered into the energy model with documented values, it will never appear in the assessment. It will save you electricity, but it will not count toward the certificate.

**Mistake six: skipping measurement and verification.** Existing-building paths measure real performance; before-and-after meter data is your strongest evidence.

A Practical Execution Roadmap: From Idea to an Accepted File

Here is the sequence we follow with institutional clients in Jeddah, ordered as it should happen rather than as it usually happens.

**1. Survey the existing glazing.** A site walk documenting glass type, thickness, tint and condition for every façade, with areas and orientations calculated. This document is the foundation of everything that follows.

**2. Read the consumption data.** Electricity bills and BMS data for at least twelve months, to establish where the cooling peak sits and what share of the total it represents.

**3. Identify priority façades.** Not all elevations are equal; the west façade in Jeddah is usually the highest-return surface and the north the lowest. Smart targeting raises return and lowers cost.

**4. Select the product by specification, not by brand name.** Define the target SHGC and VLT range with the energy engineer first, then find the product that meets it within the compatibility chart for your glass.

**5. Build a mock-up.** One floor or one wing, with comparative surface thermal measurement — we use a FLIR camera for documentation — and occupant feedback on light and glare before rolling out.

**6. Enter the values into the energy model** and compare the proposed case against the baseline to read the real impact.

**7. Execute in phases** outside working hours, with photographic documentation and batch numbers recorded per floor.

**8. Measure and verify post-occupancy** for three to twelve months, then hand the complete package to the consultant.

This sequence turns film from "a purchased material" into "a documented, auditable measure" — which is the distinction the assessment committee cares about.