Enhancing energy performance of residential buildings: optimization of roof insulation and photovoltaic electric generation

Refurbishing existing buildings is a global priority to decrease energy consumption and greenhouse gas emissions. As many existing buildings lack a thermal envelope, a common intervention involves the roof. At the same time, photovoltaic (PV) systems are often installed without considering the roof thermal integrity. This chapter aims to find the optimal roof configuration depending on building types (single-family, multi-family, apartment complex) and related implications in heating and cooling loads. It investigates how much savings can be generated through combined PV installation and roof insulation. Different insulation levels and roof typologies are considered within two options: re-roofing (roof in need of repair) and refurbishment (roof efficiency upgrade). The methodology relies on building energy simulations to explore the advantages of combining both interventions, achieving cost reductions, efficiency improvements, and renewable production. Another point of analysis is how stand-off PV arrays, with and without insulation, can impact energy needs including forecasted climate change. Additional benefits are encompassed, such as the impact from shading on roof thermal performance, with comfort implications during heat waves connected with climate-related warmings. The findings show that optimizing roof insulation with PV is a cost-effective option in existing residential buildings. Savings from insulation varied from 3% (apartment complex) to 17% (single-family). When adding PV systems to uninsulated roofs, net savings range from 55% (apartment complex) to 80% (single-family). Shading from PV arrays reduced summer cooling loads by 17% in uninsulated apartment complexes and provided comfort improvement in upper floors. The chapter shows how combining proper energy efficiency upgrades with PV installation has the potential to accelerate the clean energy transition the view of climate-neutrality by 2050.

DAGOSTINO Delia;  MADUTA Carmen; 

2025-02-27

Woodhead Publishing

JRC137996

978-0-443-23974-8 (online),   

https://www.sciencedirect.com/science/article/pii/B9780443239748000064,    https://publications.jrc.ec.europa.eu/repository/handle/JRC137996,   

10.1016/B978-0-443-23974-8.00006-4 (online),