Passive Building Envelope Retrofitting Strategies For Educational Buildings in Hot-Arid Climates: A Systematic Review of Evidence, Barriers, and Decision-Making Frameworks

Abstract

Educational buildings in hot-arid developing countries — characterised by pre-1980 uninsulated envelopes, single-pane glazing, and split-unit air conditioning — account for a disproportionate share of national electricity consumption yet remain among the least studied building typologies in the retrofit literature. This paper presents a systematic review of passive building envelope retrofitting strategies applied to educational and comparable institutional buildings in hot-arid and hot-dry climates, with a particular focus on the under-researched context of Iraq and the southern Middle East and North Africa (MENA) region. Drawing on 67 peer-reviewed studies published between 2012 and 2024, the review synthesises evidence on the performance of seven envelope retrofit categories — wall insulation, solar control coatings, air-sealing, roof retrofitting, glazing replacement, external shading, and internal shading — and critically evaluates their applicability, effectiveness, and economic feasibility under the extreme climatic and socioeconomic conditions of Iraq. The review identifies the extensive green roof as the most impactful single passive intervention in flat-roofed hot-desert buildings, a finding that challenges the dominant cold-climate narrative in which wall insulation is the primary retrofit priority. Multi-criteria decision-making (MCDM) applications in retrofit selection — particularly TOPSIS — are systematically mapped, revealing consistent under-representation of economic cost-efficiency as an evaluation criterion in heavily subsidised energy markets. The review further identifies seven clusters of Iraqi-specific retrofitting barriers, the absence of mandatory minimum envelope performance standards as the most critical structural gap, and the chronic neglect of economic feasibility in published Iraqi retrofit studies. A three-tier policy and practice framework — encompassing building code reform, tariff normalisation, and institutional capacity building — is proposed to unlock the substantial retrofit potential of the Iraqi public educational building stock. The paper concludes by identifying six priority directions for future research, including future climate scenario evaluation, lifecycle carbon assessment, and the integration of renewable energy toward nearly zero-energy building targets.