The Architecture and Environmental Impact of Passive Houses In an era defined by intensifying climate volatility and escalating energy costs, the global construction sector faces a critical imperative to reduce its carbon footprint. Traditional residential and commercial buildings are notoriously energy-intensive, accounting for a substantial percentage of global greenhouse gas emissions primarily through heating and cooling systems. In response to this environmental challenge, structural engineers and architects are increasingly turning to the Passive House design framework. Originating from a collaborative research project in Europe during the late twentieth century, this architectural standard aims to construct buildings that maintain a comfortable interior climate with negligible reliance on conventional heating or cooling mechanisms. The foundational principle of a Passive House revolves around a highly optimized building envelope. Unlike standard construction designs that allow heat to escape through minor structural gaps, a Passive House incorporates continuous, high-performance insulation. This thick thermal barrier wraps around the entire building, significantly reducing heat transfer between the interior living space and the external environment. Furthermore, architects must eliminate thermal bridges, which are localized areas of the building envelope—such as metallic window frames or concrete balconies—that possess higher thermal conductivity than the surrounding materials, allowing heat to bypass the insulation layer entirely. To complement this heavy insulation, Passive House designs mandate strict airtightness. This is achieved by sealing every structural joint and penetration point with specialised membranes and tapes. While this airtight seal successfully prevents drafts and retains structural heat, it creates an obvious physiological challenge: a lack of fresh air for the occupants. To address this issue without sacrificing thermal efficiency, every Passive House is equipped with a mechanical ventilation system featuring heat recovery capabilities. This device continuously extracts stale indoor air and introduces fresh outdoor air, passing both streams through a high-efficiency heat exchanger. As a result, up to ninety per cent of the thermal energy from the outgoing air is transferred to the incoming fresh air, maintaining air quality while preserving the internal temperature. The final core component of the framework relies on passive solar design principles. Architects carefully position the structure to maximize solar gains during colder seasons while mitigating overheating during summer months. This requires the strategic placement of large, triple-glazed windows on the equator-facing facade of the building, which allows sunlight to penetrate deeply and warm internal surfaces. Conversely, structural overhangs, external blinds, or deciduous trees are deployed to provide shade when the sun is high in the sky. By carefully balancing these thermal, mechanical, and solar elements, a Passive House can achieve an eighty per cent reduction in space heating energy demands compared to conventional regional building standards. Questions 1–6 Complete the table below. Choose NO MORE THAN TWO WORDS AND/OR A NUMBER from the passage for each answer. Write your answers in boxes 1–6 on your answer sheet.

Passive House Feature	Structural Component / Mechanism	Primary Objective / Benefit
Continuous Insulation	Thick thermal barrier	Minimises the transfer of heat between internal and external environments.
Elimination of Thermal Bridges	Removal of elements with high thermal conductivity (e.g. 1 ....................)	Prevents heat from completely bypassing the insulation layer.
Strict Airtightness	Sealing of joints using tapes and 2 ....................	Stops drafts from occurring inside the structure.
Mechanical Ventilation	Installation of a specialized 3 ....................	Captures up to 4 .................... of thermal energy from stale air to pre-heat fresh air.
Passive Solar Design	Fitting of 5 .................... on the side of the building facing the equator	Maximises heat gains from winter sunlight.
Shading Systems	Use of external blinds, trees, or 6 ....................	Controls indoor temperatures by protecting the house from overheating in summer.