Abstract

This study assesses interior-oriented envelope retrofits based on Passive House principles, applied to the British Residency of Hyderabad, now called Telangana Mahila Viswa Vidyalayam since 2022, and to Osmania University College for Women (OUCW) for the prior 70 years. This Grade 1-listed building was constructed in several phases starting in the 1790s, then remodeled and extended under Resident James Achilles Kirkpatrick from 1798 to 1805 and completed around 1808. It served as the Residency until 1947, when it was handed over to Osmania University.    Due to the conservation approach applied to the site, which does not allow any external changes, this investigation raises an as-yet unanswered question in the Passive House literature: to what degree can the standard’s performance be achieved through the interior, and to what extent can locally produced materials help achieve that?  Four envelope scenarios have been tested in EnergyPlus 25.1.0 using a shoebox model with dimensions of 8 x 6 x 4.5 m and a floor area of 48 m², driven by the Hyderabad weather file provided by ISHRAE (WMO #431280). The modeled envelope corresponds to the piano nobile, i.e., the principal floor where rooms were later used as the college's teaching spaces. It consists of approximately 550 mm-thick brick-and-lime masonry with 20 mm-thick lime plaster on both sides, a Madras Terrace roof, and single glazing without shading. Two intermediate retrofits used locally made materials: autoclaved aerated concrete (AAC) blocks, mud, and mineral wool. For a fourth scenario, 150mm of expanded polystyrene on interior walls, reflective roof coating, and triple glazing were used.  The baseline provides 227.1 kWh/m²/year of cooling energy and a peak cooling load of 2,394 W. The local material retrofit reduces the figures to 167.8 kWh/m²/year (26.1%); mineral wool insulation to 112.4 kWh/m²/year (50.5%); and the Passive House retrofit envelope to 45.6 kWh/m²/year (79.9%), with a peak load reduction of 68.3%. Another parallel scenario, which uses vapor-open wood fiber insulation instead of expanded polystyrene, provides 47.7 kWh/m²/year, i.e., it performs within 2.1 kWh/m²/year of the polystyrene scenario, thereby demonstrating that hygrothermal compatibility of this envelope does not impose a significant performance penalty.  In addition, two more outcomes of this study proved more important than initially anticipated. Restoring the building’s original louvered timber shutters, which were implemented during the 2015-2022 conservation program, alone reduces cooling energy by 31.2%, thereby surpassing all savings from locally produced retrofitting materials without any additional material cost or change to the historic fabric. Using a traditional lime wash with a solar absorptance of 0.45 on the roof surface, rather than 0.70, reduces energy consumption by another 19.3%. Taken together with the finding that the Madras Terrace roof performs better than reinforced concrete slabs used in post-independence repairs by a factor of 2.6, this suggests that a considerable part of the retrofit potential of Deccan heritage buildings is achieved through reinstatement.  The study makes four main contributions: (1) first quantitative dataset of Passive House envelope retrofit for a heritage building in semi-arid tropics of Deccan; (2) evidence that locally produced materials provide approximately a quarter of total achievable savings; (3) evidence that hygrothermal compatibility comes at virtually no performance cost; and (4) introduction of reinstatement as a separate low-cost retrofit strategy preceding any material solution.

Publication Date

8-2026

Document Type

Thesis

Student Type

Graduate

Degree Name

Architecture (M.Arch.)

Department, Program, or Center

Architecture, Department of

College

Golisano Institute for Sustainability

Advisor

Seth H. Holmes

Advisor/Committee Member

Alissa de Wit-Paul

Advisor/Committee Member

Julius J. Chiavaroli

Campus

RIT – Main Campus

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