which is the best tankless water heater to buy?
['Rinnai RUR98iN (Top Overall) ... ', 'Rinnai RUC98iN (Indoor) ... ', 'Rheem RTG-84XLN (Outdoor) ... ', 'Rheem RTGH-95XLN (Best Outdoor) ... ', 'Takagi T-KJr2 IN-NG (Indoor) ... ', 'Stiebel Eltron Tempra Plus 24 (Best Electric) ... ', 'Eemax EEM24027 (Electric) ... ', 'EcoSmart ECO 27 (Electric)']