Passive House Principles Applied to Urban Retrofit: A Retrofit Strategy for Affordable Housing in Coastal Cities

Project Abstract

This study investigates the integration of Passive House principles into urban retrofit projects aimed at delivering affordable housing in coastal cities, addressing the dual challenges of energy efficiency and resilience to climate impacts while navigating constraints of urban fabric, existing structures, and limited capital. The research adopts a mixed-methods approach, combining quantitative energy modeling, life-cycle cost analysis, and qualitative stakeholder engagement to evaluate retrofitting strategies across typologies common in coastal urban areas, including multifamily housing, mid-rise apartments, and mixed-use blocks. A baseline assessment of selected case-study buildings establishes pre-retrofit energy performance, embodied carbon, and retrofit feasibility, followed by modeled scenarios that apply Passive House criteria—continuous insulation, high-performance glazing, airtight envelopes, heat recovery ventilation, and active energy systems—adapted to retrofit realities such as structural limitations, retrofit density, and occupant behavior. The study expands conventional Passive House metrics by incorporating coastal-specific climate risks (hurricanes, sea-level rise, heat waves) and regional energy market conditions, enabling a robust assessment of resilience alongside energy performance. Key performance indicators include site energy use intensity, primary energy demand, indoor environmental quality, thermal comfort, moisture risk, and post-retrofit utility costs, all evaluated over a project’s life cycle. The research also examines financing mechanisms, procurement strategies, and policy frameworks that can accelerate adoption of low-energy retrofits in fiscally constrained urban contexts, with particular attention to equity considerations and the distribution of retrofit benefits among existing residents. Findings reveal that well-designed retrofit packages can achieve substantial reductions in energy consumption—often exceeding 60%—through a combination of envelope improvements and balanced mechanical ventilation, while ensuring indoor air quality and occupant comfort during extreme coastal weather events. The study identifies critical design decisions, such as prioritizing airtightness without compromising ventilation, selecting retrofit-friendly materials to minimize moisture-related risks, and integrating renewable energy sources where feasible to close the energy loop. Life-cycle cost analysis demonstrates favorable total costs of ownership over a 25–30 year horizon in the majority of scenarios, driven by energy savings and avoidance of costly climate-related damages, despite higher upfront capital requirements. The social dimension is explored through occupant engagement strategies, maintenance planning, and operability considerations that influence long-term performance. The research culminates in a decision-support framework that translates Passive House criteria into retrofit-ready guidelines tailored to coastal cities, including a modular typology library, stepwise retrofit phasing, and risk mitigation protocols for moisture, corrosion, and flood exposure. Policy and practice recommendations advocate for integrated design teams, standardized retrofit packages, and performance-based incentives to unlock scalable, affordable, resilient housing gains. The study contributes new insights into adapting the Passive House standard for retrofit contexts in vulnerable coastal urban environments, offering a replicable methodology for other cities pursuing energy efficiency, climate resilience, and social equity through sustainable housing retrofits.

Project Overview

What This Project Is About

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A plain-language overview of how energy-efficient and healthy buildings can be planned and renovated in urban coastal areas using Passive House ideas. The project investigates how retrofit strategies can reduce energy use, improve comfort, and lower long-term costs for affordable housing in cities near the coast, where humidity and salt air add design challenges.

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The Problem It Addresses

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Coastal cities face rising energy costs, aging building stock, and the need for affordable homes. Many existing buildings leak energy, are uncomfortable in extreme weather, and require expensive maintenance. The project asks how a standardized, proven design approach (Passive House) can be adapted to retrofit projects without sacrificing affordability or local character.

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Objectives of the Project

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1. Explain the core ideas of Passive House in plain language.
2. Assess how retrofit steps can meet energy and comfort goals for affordable housing.
3. Identify practical design strategies that work in coastal urban settings.
4. Propose a step-by-step retrofit plan for a representative housing block.
5. Discuss cost implications and long-term maintenance considerations.

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What You Will Do Step by Step

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1. Review basic Passive House concepts and terms.
2. Analyze a sample coastal building for retrofit opportunities.
3. Develop a retrofit package focusing on envelope, ventilation, and moisture control.
4. Estimate energy savings and payback using simple calculations.
5. Create a visual plan with sketches and possible material choices.
6. Outline implementation steps and risk factors.

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Expected Outcome

A clear, beginner-friendly guide showing how to retrofit affordable coastal housing using Passive House ideas, with a practical plan, estimated savings, and considerations for real-world implementation. The project aims to provide a transferable approach that practitioners can adapt to similar urban settings.