Costs and Benefits of Community Scale Solar Water Heating

Publication Type

Conference Paper

Date Published




In this paper we present a new population-level life-cycle cost (LCC) analytical framework to quantify the relative costs and benefits of deploying solar water heating (SWH) end-use technology at a community scale, in comparison to individual systems, under a wide range of conditions. A primary innovation is to provide a quantitative definition of scale parameter to distinguish between individual-and community-level projects, and to identify major aspects of system cost and performance that are impacted bya change in scale.We describe the structure of the population-level LCC model and the methodology of its sub-models as developed for a study of SWH in California. We evaluate multiple residential building types and climate zones in California to understand factors that may influence the relative performance of community-scale installations vs. individual households. We developed a new hot water demand model, as well as a new multiscale SWH cost and performance model.Our results show that there exists an optimalscale for the SWH systems. A scale of eight provides maximum LCC benefits (minimum LCC) for single-family detached, a scale of 16 or 32 for single-family attached, and 32 for multi-family households. Minimal backup water heater natural gas use occurs at scalesoftwo to four for single-family detached housing, four to eight for single-family attached, and eight to 16 for multi-family housing. We support the results with population-level illustrations of scaling and climate zone effects on the energyuse and scaling effects on installation cost, total installed cost, purchase price and LCC.


2020 Summer Study on Energy Efficiency in Buildings

Year of Publication