New York mayor Bill de Blasio recently announced his intent to reduce the city's greenhouse gas emissions by 80% over 2005 levels by 2050. According to the mayor's press office, "nearly three quarters of New York City's greenhouse gas emissions come from energy used to heat, cool, and power buildings." Hence, the first step in the mayor's plan, "One City, Built to Last: Transforming New York City's Buildings for A Low-Carbon Future," calls for the retrofitting of public and private buildings, which will increase efficiency, reduce the government's contribution to climate change, save money and create jobs. Approximately 3,000 city-owned buildings will be retrofitted by 2025 while owners of private buildings will be offered incentives to make upgrades, though mandates may be implemented if building owners resist. The plan is a win-win, as heat and hot water in large, rent-regulated apartment buildings (six or more families) is paid for by the landlord. Thus, more efficient apartments mean lower energy costs for landlords. Hot water, and the oil, gas and electricity systems required to produce it, is one of the biggest consumers of energy in residential buildings. Landlords can save money and support the mayor's plan by curbing these hot water/energy costs. But how? Low-flow shower heads have been proven to result in annual water and energy savings of up to 40%. But these devices often result in tenant discomfort and unauthorized removal of the device. The Water Scrooge, however, is a tamper-proof shower and sink regulators that reduces water usage while maintaining water pressure. This reduction in water usage can save approximately $1,000 per year per apartment. That's half a million dollars per year in a 500-unit apartment building! Prominent New York City real estate, energy and environmental advocates left a meeting at city hall optimistic about the "One City, Built to Last" plan and private building owners' support of it. Making these changes and investing in building upgrades will result in financial savings for years to come. David Schwartz is the founder of The Water Scrooge and CEO of DS Magic Tech, LLC, Lynnbrook, N.Y.