In this study, we explored cost-optimal renewable-based district heat production systems and potential to integrate solar heating in such systems under different contexts. We investigated under which conditions a solar heating system become cost-efficient to integrate in district heat production systems and the consequences of this integration. We considered a small-scale district heat production system in the south of Sweden where district-heat production cost is higher and hence it is more cost efficient to integrate solar heating in such district heat production systems. The cost-efficiency of integrating solar heating in a minimum-cost renewable-based district heat production system depends on future fuel prices and investment costs of solar heating systems. In any case, integrating solar heating will help to reduce the use of other primary energy resources as biomass.