MS 1525: Practical Compliance Guide for Malaysia

MS 1525 sets the design and operating baseline

A 4,000 m² air-conditioned area can change a design decision into a legal compliance issue. MS 1525 gives Malaysian project teams a common baseline for the building envelope, lighting, air-conditioning, controls, metering and energy management.

Its full name is “Energy efficiency and use of renewable energy for non-residential buildings, Code of Practice”. It is published as a Malaysian Standard by the Department of Standards Malaysia.

The current edition is MS 1525:2019, the third revision, which replaced MS 1525:2014. Buildings whose peak electrical design load is below 10 W/m² of gross floor area sit outside the standard.

MS 1525 mainly covers non-residential buildings such as offices, hotels, hospitals, shopping centres and institutions. Use the controlled standard, approved drawings and applicable law for a real submission.

When is MS 1525 mandatory?

MS 1525 is a standard, but part of it can become mandatory through building law. Uniform Building By-Laws (UBBL) By-Law 38A is commonly cited for new or renovated non-residential buildings where the air-conditioned space exceeds 4,000 m². The 2012 amendment requires such buildings to meet MS 1525 on Overall Thermal Transfer Value and Roof Thermal Transfer Value, and to be provided with an energy management system.

Malaysia’s UBBL is adopted through state and local arrangements. The amendment, wording or effective date may differ by area. Ask the submitting person or local authority to identify the applicable gazette, using the Local Government Department portal as a starting point.

The Energy Efficiency and Conservation Act 2024 (EECA) is a separate federal energy-management regime. It may apply to an energy consumer based on regulated criteria, not simply because a building falls under By-Law 38A. Read our dedicated EECA energy audit guide, then confirm the current regulations and thresholds on the Energy Commission’s EECA portal.

Check MS 1525 during design, the local UBBL at submission, and EECA for operating duties. One site may face all three.

What MS 1525 numbers should the design team check?

Check the envelope, roof, lighting, air-conditioning and mechanical ventilation (ACMV), controls and meters. Each needs its own calculation or record.

Overall Thermal Transfer Value limits wall and window heat

Overall Thermal Transfer Value (OTTV) estimates average heat gain through external walls and windows. It combines opaque-wall heat, glass conduction and solar gain. Lower is better because cooling has less heat to remove.

The maximum is 50 W/m² of gross exterior wall area.

A simple physical form of the calculation is:

$$OTTV = \frac{\sum_i A_i(q_{wall,i}+q_{glass,i}+q_{solar,i})}{\sum_i A_i}$$

Here, \(A_i\) is the facade area for orientation \(i\). The \(q\) terms cover wall, glass and solar heat. MS 1525 also applies orientation, absorption, thermal, glazing-ratio and shading factors.

Assume a 1,000 m² facade produces contributions of 15 W/m² from walls, 8 W/m² from glass conduction and 22 W/m² from solar gain:

$$OTTV = \frac{(15+8+22)\times 1{,}000}{1{,}000}=45\ \text{W/m}^2$$

The result is 45 W/m², which is 5 W/m² below the limit. A submission still needs every orientation, material, glazing and shading input.

Roof checks depend on construction and skylights

Roof Thermal Transfer Value (RTTV) plays a similar role for roofs with skylights. The limit is 25 W/m². For roofs without skylights, the maximum U-value is 0.4 W/m²K for lightweight roofs (below 50 kg/m²) and 0.6 W/m²K for heavier roofs.

U-value means thermal transmittance. A lower value means less heat passes through the roof.

Lighting power limits watts installed per floor area

Lighting Power Density (LPD) is the installed lighting load divided by the served floor area. The limit changes by space type. For office areas the limit is 10 W/m², a figure the Energy Commission uses in its own efficient-office guidance.

For 12,000 W of lighting across 1,000 m²:

$$LPD = \frac{12{,}000\ \text{W}}{1{,}000\ \text{m}^2}=12\ \text{W/m}^2$$

If the limit is 10 W/m², the design is 2 W/m² over. Reduce fitting wattage or quantity, while following the inclusion rules for special loads.

ACMV efficiency is an equipment and system check

Coefficient of Performance (COP) is cooling output divided by electrical input. A COP of 3.33 gives 3.33 kW of cooling per 1 kW input at the stated condition.

$$COP = \frac{100\ \text{kW cooling}}{30\ \text{kW electrical input}}=3.33$$

MS 1525 sets minimum efficiency by equipment type and capacity band in its ACMV tables (SEDA's chiller-rebate guideline points to Table 25 of the standard for minimum ratings). For chillers you will often see the same idea written as kW per refrigeration tonne, and the two convert directly:

$$\text{kW/RT} = \frac{3.517}{COP}$$

The applicable minimum depends on capacity, test standard and equipment class, so read the value off the purchased standard for your exact equipment.

Compare values at the same test condition. Keep the selection schedule, certified data, calculations, control sequences and commissioned readings.

Metering turns a design into an operating system

An energy management system (EMS) records and helps staff control energy use. By-Law 38A requires an EMS for the same buildings above 4,000 m² of air-conditioned space. MS 1525 also addresses meters and the energy information needed to separate major uses.

Design the meter schedule before the switchboard is built. Separate major loads where required, then record each meter’s ratio, network address, served load and data interval.

Who owns each compliance item?

The consultant coordinates calculations. The owner must then operate the building to the design intent.

Agree each lead and reviewer before tender to avoid late physical changes.

What should be checked at design and handover?

At design stage:

- Confirm the applicable MS 1525 edition, state UBBL amendment and local authority instructions.
- Calculate OTTV and the relevant roof measure before fixing facade materials.
- Check LPD by room type, not just as a whole-building average.
- Select ACMV equipment against the correct capacity band and test condition.
- Put meters, sensors, data networks and EMS points into drawings and specifications.
- Set an energy baseline and target. Our Building Energy Intensity guide explains the annual kilowatt-hours per square metre measure.

At handover stage:

- Match installed glass, insulation, lights and ACMV equipment to approved submissions.
- Commission sensors, meters, valves, dampers, schedules and alarms.
- Check meter readings against portable instruments and confirm meter labels.
- Give operators as-built drawings, point lists, calculation files, manuals and training.
- Record defects, the responsible person and close-out dates.
- Start trend logging before the defects liability period ends.

Handover evidence must connect the design calculation to what was installed, tested and observed.

MS 1525 is not a green-building rating

MS 1525 is a technical code of practice. Green Building Index (GBI) and GreenRE are voluntary certification schemes unless a project requirement says otherwise. They assess wider topics under their own rules.

MS 1525 calculations may support a certification submission, but passing a limit does not earn a rating or remove legal duties. See our guide to green-building certification in Malaysia.

Compliance continues after handover

OTTV is largely fixed when the facade is built. ACMV efficiency and energy management are ongoing. A good chiller can still waste energy when sensors drift, schedules run overnight, valves bypass or operators cannot see the cause of a spike.

Review monthly energy, maximum demand and major end uses. Close alarms, compare Building Energy Intensity with the baseline, and keep a clear measurement and verification (M&V) method for savings.

CobiNeural can run alone or over an existing building management system (BMS), programmable logic controller (PLC), or supervisory control and data acquisition (SCADA) system. It combines sub-metering, trends, alerts, M&V and EECA reporting. It supports the record, but does not replace design calculations, approval or an audit.

If you want to see how your existing meters and controls can feed that record, request a practical CobiNeural demo.