*Data Quality and Limitations*

LCA methodology requires a thorough analysis for all phases and conducting an LCA for existing heating technologies (oil, coal, wood, LPG boiler, and electric heater) requires significant time and data. Moreover, the use phase dominates most of the categories, so the importance of the manufacturing phase remains limited. Only use phase related GHG emissions are compared in the cumulative savings.

House archetypes and their specifications create different electricity demands and heat pump size requirements. This study compares the life cycle impacts of different archetypes by differentiating the electricity use. However, one size heat pump is considered in the LCA study. This is mainly because the data are limited in terms of amount of materials used for different sizes of heat pumps.

Replacing existing heating technologies with low-temperature heat pumps requires upgrading the heat distribution system, which could mean increasing the size of radiators or installing underfloor heating systems. Environmental impacts of underfloor heating systems are calculated in the LCA chapter to investigate the overall impact. However, financial analysis in the integrated approach only considered minor upgrades, such as increasing the size of several heat pumps to avoid high installation costs.
