In NYC alone steam boilers provide heat and hot water to over 75,000 buildings larger than 5,000 square feet citywide, so they are the most common system in NYC. Within multifamily buildings, steam is responsible for 74 percent of that sector’s carbon emissions. The same trend can be found in Boston, Chicago, Seattle and many other big cities through US. Starting 2024 energy grading system in NYC will impose significant fines for buildings with low grades. Alternative solutions, - hydronic, heat pumps, electric heating, hybrid, etc. – are expensive, require thorough insulation, labor intensive, require backup system and difficult to accomplish with tenants on premises. Conversion into vacuum heating is simple, efficient, economical and the least inconvenient for tenants approach. 2014 NGRID study confirmed 25- 50% fuel savings, vacuum system under study is still functioning today without problem. Four small residential installations support findings.