Decreasing the response time to residential fires leads to more people being saved, fewer injuries, less property damage and a lesser environmental impact. One way of reducing the response time to fires is to allow the municipal fire and rescue services to cooperate with other actors. This study evaluates a potential agreement between the fire and rescue service of a Swedish municipality (Helsingborg) and a private security officers' firm. A geographic information system (GIS) simulation is used to estimate the reduced response times. The result is combined with a statistically estimated measure of the risk of fatality for marginal changes in the response time to find the effect on survival rates and property damage. The results show that the response time is 52 s on average faster using security officers for residential fires. Combining this gain in response time with the relation to fatalities and adjusting for the fact that security officers are less effective imply a decreased death rate by 0.0105 or 1.3% per year. The project has positive economic effects with the benefits estimated to be 1.4 (saved lives) and respectively 2.3 (saved lives and property damage) times higher than the costs.