This study employs an agent-based model to examine the adoption of District Heating Networks (DHNs) in heat zoning areas, focusing on the impact of three policy interventions, subsidy, tax and mandating connections. Analysing a case in South Yorkshire, UK, the research highlights a notable synergy in policies, with a combined £25.5 million from subsidies and tax incentives leading to a 28% (£33 million) reduction in infrastructure costs. The policies accelerated the DHN connection rate, achieving full coverage by 2028, two years ahead of the baseline scenario. Investment costs per household were significantly reduced from £2000 to £1460, aligning with governmental cost projections. The study acknowledges optimistic connection rates and suggests future work to include realistic project timelines and incorporate social and behavioural factors in DHN adoption. The findings show the effectiveness of integrated policy frameworks in promoting DHNs.