Malaysia's weather is not complicated, but it is relentless. MetMalaysia sums up our climate as uniform temperature, high humidity and copious rainfall, with temperatures varying by less than 2°C across the year in most places. So a house here has two jobs, every day: keep out the scorching sun and the rain, and still let the breeze move through.

Most of this is decided early, on paper. Getting it right at the drawing stage costs far less than fixing it once the house is built.

Start with orientation

Malaysia sits just north of the equator, so the sun passes high overhead for much of the day, drifting a little north around June and a little south around December. The walls that take the most punishment face east and west, where the low morning and afternoon sun shines straight into the windows.

That is why MS 2680, Malaysia's energy-efficiency code of practice for residential buildings, advises against facades with most of their openings facing east or west. (Its counterpart, MS 1525, covers non-residential buildings, not homes.) For terrace houses, it recommends front and back facades facing north and south. The catch is the end unit: its long side wall then faces east or west, so it needs fewer windows, awnings or a covered terrace.

Where you can, put the main windows on the north and south, and use stairs, stores or bathrooms on the east and west as buffers. And don't write off the east as the "easy" side: the Public Works Department's BSEEP passive design guideline notes that direct sun is, on average, stronger in the morning, since afternoons tend to be cloudier.

Shade the windows, not just the walls

MS 2680 says every window should have an overhang or fins, and that external shading works better than internal blinds or curtains. BSEEP's simulations with Malaysian weather data give a handy rule of thumb: an overhang that projects as far as the window below it is tall roughly halves the solar heat coming through that window, and one about a third of the window height cuts it by around a quarter.

North and south windows are the easiest to handle. MS 2680's guidance for Kuala Lumpur shows they can be fully shaded, while a typical east-facing shade only works from about 9am and a west-facing one until about 5pm. East and west windows need deeper overhangs plus vertical fins, screens or louvres, or simply less glass. A common mistake: a wall of west-facing glass with nothing but curtains inside to shade it.

Let the breeze through

Cross ventilation means air can come in on one side of a room and leave on the other. A Universiti Teknologi Malaysia (UTM) field study of a terrace house in Kuching measured essentially still air in a bedroom ventilated from one side only, with conditions most people would find too warm. The authors concluded that the by-law minimum, openings equal to 10% of floor area, does not on its own guarantee comfort.

MS 2680 recommends openings on opposite walls (or at least adjacent ones) with nothing blocking the path, plus high openings or a ventilated stairwell so warm air can rise and escape. The Green Building Index (GBI) residential tool rewards homes where at least 75% of habitable rooms are ventilated this way. The traditional Malay house did it with few partitions, full-length windows and screened gables.

Timing matters too. BSEEP's Klang Valley weather data shows outdoor air is below 29°C, the comfort limit BSEEP uses for naturally ventilated rooms, for about 37.5% of the hours in a year, mostly from late afternoon to mid-morning. At midday, open windows mainly let in hot air. So ask for windows you can open wide, and securely, when it is cooler.

Deep eaves for sun and rain

MetMalaysia describes the Northeast Monsoon (November to March) as our main rainy season, hitting the east coast of the Peninsula, western Sarawak and eastern Sabah hardest. The Southwest Monsoon (late May to September) is relatively drier, but the west coast still gets early-morning "Sumatra" squalls with strong gusts and heavy rain. When the wind picks up, rain drives sideways into walls, frames and doors.

MS 2680 recommends high-pitched roofs to shed heavy rain and large overhangs to shade walls and openings. A Canadian field study on a six-storey building found a 1.2 m overhang cut the wind-driven rain reaching the wall by about 60%. The climate there is different, but the principle holds. Yet UiTM researchers note that cost and profit pressures in housing estates have cut eaves short and made shady verandahs disappear.

Worth asking for: deeper eaves on the side facing your local rain, a covered porch at the entrance, a verandah on the hottest side, and windows tucked under the eaves so they can stay open in light rain.

Questions to ask before the design is fixed

  • Which walls face east and west, and how are their windows shaded?
  • How deep is each overhang compared with the window below it?
  • Can air flow through each bedroom and the living area, not just into it?
  • Can windows stay open safely at night and in light rain?
  • If costs are cut later, will eaves and shading be the first to go?

Sources

  1. Malaysian Meteorological Department (MetMalaysia), "Malaysia's Climate": uniform temperature, high humidity, copious rainfall; annual temperature variation under 2°C (under 3°C on the east coast); cool nights. https://www.met.gov.my/en/pendidikan/iklim-malaysia/
  2. MetMalaysia, "Weather Phenomena": Southwest Monsoon late May to September, Northeast Monsoon November to March as main rainy season; "Sumatra" squall lines on the west coast; thunderstorms most frequent April to May and October to November. https://www.met.gov.my/en/pendidikan/fenomena-cuaca/
  3. Department of Standards Malaysia, MS 2680:2017, Energy efficiency and use of renewable energy for residential buildings: Code of practice (policy entry via UN ESCAP policy database): avoid facades with most openings facing east or west; terrace front/back facades north and south, end-unit strategies; high sun altitude year-round; high-pitched roofs and large overhangs; overhangs or fins on all windows; external shading more effective than internal; Kuala Lumpur shadow-angle table (N/S full shading, E from 09:00, W until 17:00); cross and stack ventilation guidance; sun path over the year (Annex A). https://policy.asiapacificenergy.org/node/1268
  4. International Energy Agency, policy entry for MS 1525:2019, Energy efficiency and use of renewable energy for non-residential buildings: scope limited to non-residential buildings. https://www.iea.org/policies/30611-ms-1525-energy-efficiency-and-use-of-renewable-energy-for-non-residential-buildings
  5. Building Sector Energy Efficiency Project (BSEEP), JKR/UNDP, Building Energy Efficiency Technical Guideline for Passive Design (2013), lead consultant CK Tang: sun path over Malaysia; glazing facing north/south uses less energy than east/west; morning direct radiation and east-facade shading; horizontal-shade SHGC by overhang-to-window-height ratio (ratio 1.0: SHGC 0.49 to 0.53; ratio 0.35: 0.71 to 0.75); Subang (Klang Valley) weather data showing air below 29°C for 37.5% of hours, mostly late afternoon to mid-morning; internal shades generally less effective than external. https://www.mgbc.org.my/wp-content/uploads/2023/01/BSEEP-Passive-Design-Guidebook-Final.pdf
  6. Greenbuildingindex Sdn Bhd, GBI Assessment Criteria for Residential New Construction (RNC), Version 3.0 (July 2013), EQ1: at least 75% of habitable rooms with cross and/or stack ventilation. https://www.greenbuildingindex.org/Files/Resources/GBI%20Tools/GBI%20RNC%20Residential%20Tool%20V3.0.pdf
  7. Leng, P.C., Ling, G.H.T., Ahmad, M.H. et al. (2021, published online December 2020), "Thermal Performance of Single-Story Air-Welled Terraced House in Malaysia: A Field Measurement Approach," Sustainability 13(1), 201 (Universiti Teknologi Malaysia): still air (0.00 m/s) and warm conditions in single-sided test room; UBBL 10% opening minimum judged insufficient on its own. https://www.mdpi.com/2071-1050/13/1/201
  8. Kamal, K.S., Abdul Wahab, L. & Che Ahmad, A. (2004), "Climatic design of the traditional Malay house to meet the requirements of modern living," ANZAScA conference (Universiti Teknologi MARA Perak): screened gables for ventilation and driving-rain protection; full-length windows; minimal partitions; cost pressures cutting large eaves and verandahs. http://anzasca.net/wp-content/uploads/2014/08/ANZAScA2004_Kamal.pdf
  9. Nik Hassin, N.S.F. & Misni, A. (2025), "Evaluation of Architectural Design Features of Melaka Traditional Malay House with Open Interior Space Affecting Its Thermal Performance," Journal of Construction in Developing Countries 30(Supp. 1), Penerbit USM: traditional Malay house features including minimal interior walls for cross ventilation, raised floors, ventilated roof space and broad eaves controlling direct sun. http://web.usm.my/jcdc/vol30_s1_2025/jcdc2025.30.s1.7.pdf
  10. BC Housing and Concordia University, Using Overhangs to Reduce Building Facade Exposure to Rain: 1.2 m overhang reduced wind-driven rain on the whole facade by about 60% (field study, British Columbia). https://www.bchousing.org/publications/Overhangs-Rain-Exposure-Study.pdf