Objectives MePACS is a triage and support-based personal alarm emergency response system designed to assist older and/or disabled people to live safely in their homes. The aim of this study was to estimate avoidable ambulance attendances and transports to emergency departments and quantify the cost savings attributed to MePACS compared with a comparison cohort without a personal alarm system. Methods Alarm activation and demographic data for clients registered in the program from June 2016 to May 2017 and funded through the Personal Alert Victoria program were extracted from routinely collected MePACS electronic data. Information on alarm use, event outcomes and ambulance attendances was extracted. Using published Ambulance Victoria data, a comparison cohort was simulated to model the experience of a similar cohort without access to a personal alarm system who experienced a health emergency and called Australia's emergency call service number. The incremental management cost, incorporating the operation cost of MePACS and ambulance fees, was calculated to compare the potential cost savings of MePACS with the comparison cohort. Results Among 18421 eligible clients, there were 7856 emergency alarm activations due to falls or medical events from 4275 clients (79.5% female; 81.1% aged >75 years; 91.8% living alone). MePACS resulted in approximately one-third of ambulance attendances being avoided. Potential annual cost savings of A$1414732.8 (A$76.8 per person per year; 95% confidence interval A$60.0-93.6 per person per year; P<0.001) were attributed to avoidable ambulance utilisations for 18421 MePACS clients. Conclusion Triage-based personal alarm systems, such as MePACS, provide a cost-saving strategy because of fewer ambulance attendances and transports to emergency departments for older and/or disabled people living in the community. What is known about the topic? Personal alarm systems, either a safety alarm, a panic alarm or a medical alarm, have been widely used to support older people and at-risk groups to live independently. The health effects of personal alarm systems are well documented. There is limited information published on the potential economic benefits of these interventions. What does this paper add? We identified the potential economic benefits associated with the MePACS triage-based personal alarm system operating within Victoria, Australia. Personal alarm systems that are triage based and use the support of family members and carers may provide financial benefits not provided by alarm systems that do not provide this type of service. What are the implications for practitioners? The management of older people and at-risk groups living alone is a health care priority. Alternative models to calling emergency services, such as triage-based personal emergency response systems, may provide a low-cost, effective approach.