Operation Installation (OI), a community-based smoke alarm installation programme in Dallas, Texas, targets houses in high-risk urban census tracts. Residents of houses that received OI installation (or programme houses) had 68% fewer medically treated house fire injuries (non-fatal and fatal) compared with residents of non-programme houses over an average of 5.2 years of follow-up during an effectiveness evaluation conducted from 2001 to 2011.To estimate the cost-benefit of OI.A mathematical model incorporated programme cost and effectiveness data as directly observed in OI. The estimated cost per smoke alarm installed was based on a retrospective analysis of OI expenditures from administrative records, 2006-2011. Injury incidence assumptions for a population that had the OI programme compared with the same population without the OI programme was based on the previous OI effectiveness study, 2001-2011. Unit costs for medical care and lost productivity associated with fire injuries were from a national public database.From a combined payers' perspective limited to direct programme and medical costs, the estimated incremental cost per fire injury averted through the OI installation programme was $128,800 (2013 US$). When a conservative estimate of lost productivity among victims was included, the incremental cost per fire injury averted was negative, suggesting long-term cost savings from the programme. The OI programme from 2001 to 2011 resulted in an estimated net savings of $3.8 million, or a $3.21 return on investment for every dollar spent on the programme using a societal cost perspective.Community smoke alarm installation programmes could be cost-beneficial in high-fire-risk neighbourhoods.