As mentioned in Part 1, we have decided to investigate purchasing and having installed a tankless water heater.由於部分提到，在一，我們已決定進行調查，購買和擁有tankless安裝了熱水器。 However, if we do it must meet four conditions:不過，如果我們這樣做必須符合四個條件：
Natural gas as the energy source天然氣作為能源來源
Sufficiently sized to meet our hot water needs充分大中，以滿足我們的熱水需求
Product manufactured by and installed by reputable companies to reduce the risk of unsatisfactory product performance and/or installation, […]產品的製造和安裝的有信譽的公司，以減少風險，不理想的產品性能和/或安裝， [ … … ]
