System requirement specification for one stop shop housing retrofit

the system is an online information system, which can be accessed through a web browser or as a mobile app. The user can be any adult who has general computer literacy and access to a device with the internet. As the UK has 30 million housing stock, the maximum number of users will be 30 million. There are institutional users such as retrofit installers, professionals or financing partners. It is difficult to estimate the number of such users at this level. The system shall cover all the parts of the UK. As the housing decarbonisation goals are to be achieved before 2050, the system is expected to be terminated by 2050. There are no restrictions on the house type. If an EPC report can be generated for a house, such a house can be used for the proposed system. However, the level of accuracy will be maximum for simpler houses. When it comes to housing retrofit, several stages can be identified. This system shall work up to the stage when the homeowner decides to contact a retrofit assessor for an in-person retrofit assessment. Once the decision is made, the next step starts with the retrofit assessment by the retrofit assessor. Currently, there are different systems developed by different accreditation bodies for retrofit assessment. If the proposed system can be combined with a retrofit assessment system and further retrofit coordination process, it will be highly valuable for the homeowner to have a better informed and included experience. However, that is beyond the scope of this proposal.本系统为在线信息系统，支持通过网页浏览器或移动应用程序（mobile app）访问。系统用户为具备基础计算机操作能力、可接入联网设备的成年个体。鉴于英国现有住房存量达3000万套，本系统的最大用户规模可达3000万。机构用户涵盖房屋改造安装商、专业技术人员及融资合作伙伴等，现阶段暂无法准确估算该类用户的规模。系统服务范围覆盖英国全境。由于英国住房脱碳目标需在2050年前达成，本系统预计将于2050年停止运营。本系统对房屋类型无限制，若某住宅可生成EPC报告（Energy Performance Certificate），则该住宅可适配本系统，但针对结构更简单的住宅，系统的测算精度可达最高。在房屋改造（retrofit）流程中，可划分多个阶段；本系统的服务覆盖至房主决定联系改造评估师（retrofit assessor）开展现场改造评估前的全部环节。一旦房主做出该决定，后续流程将由改造评估师开展现场评估环节开启。目前，不同认证机构已开发出多款用于房屋改造评估的系统。若本系统可与改造评估系统及后续房屋改造协调流程进行整合，将能够帮助房主获得信息更充分、参与度更高的服务体验，具备极高的实用价值。但该整合工作不在本提案的覆盖范围之内。