Conventional district heating and cooling (DHC) systems have to reduce their fossil fuels dependence while ensuring profitability as the cooling and heating demands are decreasing. One of the solutions for these issues is to retrofit the system with a gasifier and product gas upgrading equipment so that the system will be able to diversify its fuel input, including biomass resources, and can simultaneously produce synthetic natural gas (SNG), synthetic gas (SG) and char complimentary to heat, cold and electricity. The main objective of this study is to assess energetically and economically a polygeneration DHC system, based on the gasification of refuse derived fuels, which is able to fabricate the following set of sub-products: char or SG and char or SNG and char or SG, SNG and char. This study revealed that when char is the only sub-product of the modified DHC system, the investment payback is 3 years, the discounted net cash flow (DNCF) is 142.4 mln USD, and the system trigeneration efficiency is 83.6%. When other sub-products are fabricated by the system, its performance reduces, but the system DNCF increases, while the investment payback remains invariable.