TanklesslyEndless hot water, sized to your fixtures.

Gas · Electric · Point-of-use · Flush kits · Venting

Size it to the fixtures, not the box.

Pick how many showers and taps run at once and how cold your water gets in winter. The flow your heater must hold is worked out live, and every gas and electric unit we cover is checked against it at that temperature rise, with its amps or gas load beside it.

Compare gas tankless Check amps and gas load
489
products researched
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brands covered
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categories compared
A plumbed mechanical room: insulated hot-water lines, red shut-off valves and temperature gauges on a warm-painted wall
Flow checkGas and electric tankless
120°F Heater ShowerShowerSink 5.5 GPM at a 63°F rise Inlet 57°F

207 tankless heaters state an input rating

  1. Camplux ME40B 1.44 kW Point-of-Use Tankless Water Heater1.4 kW · about – GPM at your rise
  2. Stiebel Eltron Mini 2.5-1 2.4 kW Point-of-Use Tankless Water Heater2.4 kW · up to 2.0 GPM · about – GPM at your rise
  3. Daordaer LF-001A 3 kW Point-of-Use Tankless Water Heater3.0 kW · up to 1.6 GPM · about – GPM at your rise
  4. Eemax EEM12004 4 kW Point-of-Use Tankless Water Heater4.0 kW · up to 0.5 GPM · about – GPM at your rise
  5. Camplux TE05 4.5 kW Point-of-Use Tankless Water Heater4.5 kW · up to 1.0 GPM · about – GPM at your rise
  6. Camplux TE05N4 4.5 kW Point-of-Use Tankless Water Heater4.5 kW · up to 1.0 GPM · about – GPM at your rise
  7. Stiebel Eltron DHC 4-3 Classic 4.5 kW Point-of-Use Tankless Water Heater4.5 kW · about – GPM at your rise
  8. Bosch 7738007416 6.5 kW Point-of-Use Tankless Water Heater6.5 kW · about – GPM at your rise
  9. SIVUATEK M1-65B 6.5 kW Point-of-Use Tankless Water Heater6.5 kW · up to 1.5 GPM · about – GPM at your rise
  10. Westinghouse WET-6K5-D 6.5 kW Point-of-Use Tankless Water Heater6.5 kW · about – GPM at your rise
  11. Eemax HA008240 8 kW Point-of-Use Tankless Water Heater8.0 kW · up to 3.0 GPM · about – GPM at your rise
  12. Ranein RE8K-U 8 kW Point-of-Use Tankless Water Heater8.0 kW · up to 1.9 GPM · about – GPM at your rise
  13. Rheem RTEX-08 8 kW Point-of-Use Tankless Water Heater8.0 kW · about – GPM at your rise
  14. ThermoMate ET080 8 kW Point-of-Use Tankless Water Heater8.0 kW · about – GPM at your rise
  15. VancEpic RE8K 8 kW Point-of-Use Tankless Water Heater8.0 kW · about – GPM at your rise
  16. WINTEMP WN08 8 kW Point-of-Use Tankless Water Heater8.0 kW · up to 1.9 GPM · about – GPM at your rise
  17. WINTEMP YQ-WN8K 8 kW Point-of-Use Tankless Water Heater8.0 kW · up to 1.9 GPM · about – GPM at your rise
  18. Westinghouse WET-08K-G 8 kW Point-of-Use Tankless Water Heater8.0 kW · about – GPM at your rise
  19. Titan N85 8.5 kW Point-of-Use Tankless Water Heater8.5 kW · up to 2.3 GPM · about – GPM at your rise
  20. Titan N-100 10.8 kW Electric Tankless Water Heater10.8 kW · up to 2.0 GPM · about – GPM at your rise
  21. Camplux TEW11-CA 11 kW Electric Tankless Water Heater11.0 kW · up to 2.6 GPM · about – GPM at your rise
  22. Camplux TEW11N 11 kW Electric Tankless Water Heater11.0 kW · up to 2.6 GPM · about – GPM at your rise
  23. Electrolux 11-2 11 kW Electric Tankless Water Heater11.0 kW · about – GPM at your rise
  24. LiberLive REK11/13 11 kW Electric Tankless Water Heater11.0 kW · up to 2.6 GPM · about – GPM at your rise
  25. Rheem RTEX-11 Electric Tankless Water Heater11.0 kW · up to 2.7 GPM · about – GPM at your rise
  26. ThermoMate ET110 11 kW Electric Tankless Water Heater11.0 kW · up to 2.7 GPM · about – GPM at your rise
  27. ThermoMate ET110HCUS 11 kW Electric Tankless Water Heater11.0 kW · about – GPM at your rise
  28. WINTEMP WN11 Electric Tankless Water Heater11.0 kW · up to 2.6 GPM · about – GPM at your rise
  29. WINTEMP YQ-WN11K 11 kW Electric Tankless Water Heater11.0 kW · up to 2.6 GPM · about – GPM at your rise
  30. Westinghouse WET011A0G 11 kW Electric Tankless Water Heater11.0 kW · up to 2.6 GPM · about – GPM at your rise
  31. EcoSmart ECOS 12 Electric Tankless Water Heater12.0 kW · up to 2.9 GPM · about – GPM at your rise
  32. Stiebel Eltron Tempra 12 Plus 12 kW Electric Tankless Water Heater12.0 kW · up to 3.0 GPM · about – GPM at your rise
  33. Stiebel Eltron Tempra 12 Trend 12 kW Electric Tankless Water Heater12.0 kW · up to 7.0 GPM · about – GPM at your rise
  34. Rinnai RE140eP Propane Tankless Water Heater41,096 BTU/h · up to 5.3 GPM · about – GPM at your rise
  35. EcoSmart ECO 11 13 kW Electric Tankless Water Heater13.0 kW · about – GPM at your rise
  36. Eemax EEM24013 13 kW Electric Tankless Water Heater13.0 kW · about – GPM at your rise
  37. LiberLive RE13K 13 kW Electric Tankless Water Heater13.0 kW · up to 3.1 GPM · about – GPM at your rise
  38. Midea MHE13W2AWW 13 kW Electric Tankless Water Heater13.0 kW · about – GPM at your rise
  39. Rheem RTEX-13 Electric Tankless Water Heater13.0 kW · up to 4.8 GPM · about – GPM at your rise
  40. VancEpic RE13K 13 kW Electric Tankless Water Heater13.0 kW · about – GPM at your rise
  41. WINTEMP YQ-WN13K 13 kW Electric Tankless Water Heater13.0 kW · up to 3.1 GPM · about – GPM at your rise
  42. WINTEMP WN13 13.8 kW Electric Tankless Water Heater13.8 kW · up to 3.1 GPM · about – GPM at your rise
  43. Atmor AT-905-14TB 14 kW Electric Tankless Water Heater14.0 kW · about – GPM at your rise
  44. MIZUDO Classic 14 Electric Tankless Water Heater14.0 kW · up to 3.4 GPM · about – GPM at your rise
  45. Orbek HEU-ET014A5W-A5 14 kW Electric Tankless Water Heater14.0 kW · about – GPM at your rise
  46. SIVUATEK TSB-140 14 kW Electric Tankless Water Heater14.0 kW · up to 3.3 GPM · about – GPM at your rise
  47. SIVUATEK TSB-140 Air 14 kW Electric Tankless Water Heater14.0 kW · up to 3.3 GPM · about – GPM at your rise
  48. SIVUATEK V7B-140B 14 kW Electric Tankless Water Heater14.0 kW · up to 2.3 GPM · about – GPM at your rise
  49. ThermoMate EH140 14 kW Electric Tankless Water Heater14.0 kW · up to 3.4 GPM · about – GPM at your rise
  50. ThermoMate ET140 14 kW Electric Tankless Water Heater14.0 kW · up to 3.3 GPM · about – GPM at your rise
  51. Westinghouse HEU-ET014KA1G-A2 14 kW Electric Tankless Water Heater14.0 kW · about – GPM at your rise
  52. Stiebel Eltron Tempra 15 Trend 14.4 kW Electric Tankless Water Heater14.4 kW · up to 1.5 GPM · about – GPM at your rise
  53. Camplux TEW18 Electric Tankless Water Heater18.0 kW · about – GPM at your rise
  54. EcoSmart ECOS 18 Electric Tankless Water Heater18.0 kW · up to 4.4 GPM · about – GPM at your rise
  55. Midea MHE18W2AWW 18 kW Electric Tankless Water Heater18.0 kW · about – GPM at your rise
  56. Orbek ET018 18 kW Electric Tankless Water Heater18.0 kW · about – GPM at your rise
  57. Orbek HEU-ET018A5W-M0 18 kW Electric Tankless Water Heater18.0 kW · about – GPM at your rise
  58. Ranein RE18K 18 kW Electric Tankless Water Heater18.0 kW · up to 4.3 GPM · about – GPM at your rise
  59. SIVUATEK TSB-180 18 kW Electric Tankless Water Heater18.0 kW · about – GPM at your rise
  60. SIVUATEK V7B-180B 18 kW Electric Tankless Water Heater18.0 kW · up to 2.8 GPM · about – GPM at your rise
  61. ThermoMate EH180 18 kW Electric Tankless Water Heater18.0 kW · up to 4.4 GPM · about – GPM at your rise
  62. ThermoMate ET180 18 kW Electric Tankless Water Heater18.0 kW · up to 4.4 GPM · about – GPM at your rise
  63. VancEpic RE18K-C 18 kW Electric Tankless Water Heater18.0 kW · up to 0.5 GPM · about – GPM at your rise
  64. WINTEMP YQ-WN18K 18 kW Electric Tankless Water Heater18.0 kW · up to 4.3 GPM · about – GPM at your rise
  65. Westinghouse ET018CA0G 18 kW Electric Tankless Water Heater18.0 kW · up to 4.2 GPM · about – GPM at your rise
  66. Westinghouse ET018KA1G 18 kW Electric Tankless Water Heater18.0 kW · up to 4.2 GPM · about – GPM at your rise
  67. Mount Steel MST-TLS18A 19 kW Electric Tankless Water Heater19.0 kW · about – GPM at your rise
  68. Camplux CX264WLP 68,000 BTU Propane Tankless Water Heater65,000 BTU/h · up to 2.6 GPM · about – GPM at your rise
  69. Stiebel Eltron Tempra 20 Plus 19.2 kW Electric Tankless Water Heater19.2 kW · up to 3.8 GPM · about – GPM at your rise
  70. Stiebel Eltron Tempra 20 Trend 19.2 kW Electric Tankless Water Heater19.2 kW · up to 2.0 GPM · about – GPM at your rise
  71. Camplux CX264WNG 68,000 BTU Natural Gas Tankless Water Heater68,000 BTU/h · about – GPM at your rise
  72. Ranein TMYD-01020120 68,000 BTU Propane Outdoor Tankless Water Heater68,000 BTU/h · up to 3.2 GPM · about – GPM at your rise
  73. VELPAX HWRSQ-18L-001 Propane Tankless Water Heater68,000 BTU/h · about – GPM at your rise
  74. ThermoMate CZ264NGCA 75,000 BTU Natural Gas Tankless Water Heater75,000 BTU/h · about – GPM at your rise
  75. APUS AP-AWH-Q10NG 80,000 BTU Natural Gas Tankless Water Heater80,000 BTU/h · up to 3.6 GPM · about – GPM at your rise
  76. LiberLive HKRV-HR2110 80,000 BTU Propane Tankless Water Heater80,000 BTU/h · up to 3.6 GPM · about – GPM at your rise
  77. Ranein RH8K-LPG-FC-RATING 80,000 BTU Propane Tankless Water Heater80,000 BTU/h · up to 3.6 GPM · about – GPM at your rise
  78. Ranein RH8K-NG 80,000 BTU Natural Gas Tankless Water Heater80,000 BTU/h · up to 3.6 GPM · about – GPM at your rise
  79. VancEpic V-RH8K-LPG 80,000 BTU Propane Tankless Water Heater80,000 BTU/h · about – GPM at your rise
  80. CRAFTSMAN CMXTEPA0024 24 kW Electric Tankless Water Heater24.0 kW · up to 4.6 GPM · about – GPM at your rise
  81. Camplux TEW24 Electric Tankless Water Heater24.0 kW · about – GPM at your rise
  82. Eemax HA024240 24 kW Electric Tankless Water Heater24.0 kW · about – GPM at your rise
  83. FOGATTI ET24 Electric Tankless Water Heater24.0 kW · up to 6.0 GPM · about – GPM at your rise
  84. Rheem RTEX-24 Electric Tankless Water Heater24.0 kW · up to 5.9 GPM · about – GPM at your rise
  85. SIVUATEK V7B-240B 24 kW Electric Tankless Water Heater24.0 kW · up to 6.5 GPM · about – GPM at your rise
  86. Stiebel Eltron Tempra 24 Trend 24 kW Electric Tankless Water Heater24.0 kW · about – GPM at your rise
  87. ThermoMate ET240 24 kW Electric Tankless Water Heater24.0 kW · up to 5.8 GPM · about – GPM at your rise
  88. VELPAX VX-CT06 Propane Tankless Water Heater81,888 BTU/h · about – GPM at your rise
  89. Westinghouse ET024CA0G 24 kW Electric Tankless Water Heater24.0 kW · up to 5.6 GPM · about – GPM at your rise
  90. Westinghouse WET-24K-G 24 kW Electric Tankless Water Heater24.0 kW · up to 5.6 GPM · about – GPM at your rise
  91. forimo CT1314-HWRSQ Tankless Water Heater81,888 BTU/h · about – GPM at your rise
  92. forimo CT1412-HWRSQ Propane Tankless Water Heater81,888 BTU/h · about – GPM at your rise
  93. Camplux CX360 82,000 BTU Propane Tankless Water Heater82,000 BTU/h · up to 3.6 GPM · about – GPM at your rise
  94. RIWORY RWRHT007 85,000 BTU Propane Tankless Water Heater85,000 BTU/h · up to 3.6 GPM · about – GPM at your rise
  95. RIWORY RWRHT008 85,000 BTU Natural Gas Tankless Water Heater85,000 BTU/h · up to 3.6 GPM · about – GPM at your rise
  96. SNDOAS IF.JSQ25-B13NA Natural Gas Tankless Water Heater85,300 BTU/h · up to 4.2 GPM · about – GPM at your rise
  97. Camplux TEW27 Electric Tankless Water Heater27.0 kW · about – GPM at your rise
  98. EcoSmart ECOS 27 Electric Tankless Water Heater27.0 kW · up to 6.6 GPM · about – GPM at your rise
  99. SIVUATEK TSB-270 27 kW Electric Tankless Water Heater27.0 kW · about – GPM at your rise
  100. ThermoMate EH270 27 kW Electric Tankless Water Heater27.0 kW · up to 6.6 GPM · about – GPM at your rise
  101. ThermoMate ET270 27 kW Electric Tankless Water Heater27.0 kW · up to 5.3 GPM · about – GPM at your rise
  102. VancEpic RE27K 27 kW Electric Tankless Water Heater27.0 kW · about – GPM at your rise
  103. WINTEMP YQ-WN27K 27 kW Electric Tankless Water Heater27.0 kW · up to 6.5 GPM · about – GPM at your rise
  104. APUS AP-AWH-Q13LPG 95,000 BTU Propane Tankless Water Heater95,000 BTU/h · up to 4.4 GPM · about – GPM at your rise
  105. APUS AP-AWH-Q13NG 95,000 BTU Natural Gas Tankless Water Heater95,000 BTU/h · up to 4.4 GPM · about – GPM at your rise
  106. Stiebel Eltron Tempra 29 Plus 28.8 kW Electric Tankless Water Heater28.8 kW · up to 3.0 GPM · about – GPM at your rise
  107. Stiebel Eltron Tempra 29 Trend 28.8 kW Electric Tankless Water Heater28.8 kW · up to 9.5 GPM · about – GPM at your rise
  108. GASLAND CG360NG 98,500 BTU Natural Gas Tankless Water Heater98,500 BTU/h · up to 4.0 GPM · about – GPM at your rise
  109. ThermoMate CZ360LP 98,500 BTU Propane Tankless Water Heater98,500 BTU/h · up to 4.0 GPM · about – GPM at your rise
  110. ThermoMate CZ360NG 98,500 BTU Natural Gas Tankless Water Heater98,500 BTU/h · up to 4.0 GPM · about – GPM at your rise
  111. Orbek HW100 100,000 BTU Propane Tankless Water Heater100,000 BTU/h · up to 4.3 GPM · about – GPM at your rise
  112. Ranein RH10K 100,000 BTU Natural Gas Tankless Water Heater100,000 BTU/h · up to 4.3 GPM · about – GPM at your rise
  113. VEVOR JSQ30-A 100,000 BTU Tankless Water Heater100,000 BTU/h · about – GPM at your rise
  114. VEVOR JSQ30-B 100,000 BTU Propane Tankless Water Heater100,000 BTU/h · about – GPM at your rise
  115. Camplux CA422 102,000 BTU Propane Tankless Water Heater102,000 BTU/h · up to 4.2 GPM · about – GPM at your rise
  116. Camplux CA422-NG 102,000 BTU Natural Gas Tankless Water Heater102,000 BTU/h · up to 4.2 GPM · about – GPM at your rise
  117. Heatrova TGHT001 102,000 BTU Propane Tankless Water Heater102,000 BTU/h · up to 4.3 GPM · about – GPM at your rise
  118. Heatrova TGHT002 102,000 BTU Natural Gas Tankless Water Heater102,000 BTU/h · up to 4.3 GPM · about – GPM at your rise
  119. RIWORY RWRHT010 102,000 BTU Natural Gas Tankless Water Heater102,000 BTU/h · up to 4.3 GPM · about – GPM at your rise
  120. SNDOAS IF.JSQ30-W16NA 102,000 BTU Natural Gas Tankless Water Heater102,000 BTU/h · up to 4.8 GPM · about – GPM at your rise
  121. GASLAND CS422BLP 113,000 BTU Propane Tankless Water Heater113,000 BTU/h · up to 5.0 GPM · about – GPM at your rise
  122. ThermoMate CZ422LP Propane Tankless Water Heater113,000 BTU/h · up to 5.0 GPM · about – GPM at your rise
  123. ThermoMate CZ422NG Natural Gas Tankless Water Heater113,000 BTU/h · up to 5.0 GPM · about – GPM at your rise
  124. ThermoMate CZ480LP Propane Tankless Water Heater114,000 BTU/h · up to 5.3 GPM · about – GPM at your rise
  125. ThermoMate CZ480NG Natural Gas Condensing Tankless Water Heater114,000 BTU/h · up to 5.3 GPM · about – GPM at your rise
  126. APUS AP-AWH-Q16NG 120,000 BTU Natural Gas Tankless Water Heater120,000 BTU/h · up to 5.4 GPM · about – GPM at your rise
  127. FOGATTI 120S Propane Outdoor Tankless Water Heater120,000 BTU/h · up to 5.1 GPM · about – GPM at your rise
  128. MIZUDO FDG-CS120AW-LP 120,000 BTU Propane Tankless Water Heater120,000 BTU/h · up to 5.1 GPM · about – GPM at your rise
  129. Noritz NR50ODLP Propane Outdoor Tankless Water Heater120,000 BTU/h · up to 5.0 GPM · about – GPM at your rise
  130. Orbek HS120 120,000 BTU Natural Gas Outdoor Tankless Water Heater120,000 BTU/h · up to 5.1 GPM · about – GPM at your rise
  131. Ranein RH12KG-C-NG 120,000 BTU Natural Gas Condensing Tankless Water Heater120,000 BTU/h · up to 5.1 GPM · about – GPM at your rise
  132. Westinghouse AMZ-HS120A1G-LP 120,000 BTU Propane Outdoor Tankless Water Heater120,000 BTU/h · up to 5.1 GPM · about – GPM at your rise
  133. Westinghouse AMZ-HS120A1G-NG 120,000 BTU Natural Gas Outdoor Tankless Water Heater120,000 BTU/h · up to 5.1 GPM · about – GPM at your rise
  134. Westinghouse AMZ-HW120A1G-NG 120,000 BTU Natural Gas Tankless Water Heater120,000 BTU/h · up to 5.1 GPM · about – GPM at your rise
  135. Atmor AT-36N-XTP 36 kW Electric Tankless Water Heater36.0 kW · about – GPM at your rise
  136. Eemax EEM24036 36 kW Electric Tankless Water Heater36.0 kW · about – GPM at your rise
  137. Eemax HA036240 36 kW Electric Tankless Water Heater36.0 kW · up to 8.0 GPM · about – GPM at your rise
  138. Rheem RETEX-36 Electric Tankless Water Heater36.0 kW · about – GPM at your rise
  139. Rheem RTEX-36 Electric Tankless Water Heater36.0 kW · up to 6.0 GPM · about – GPM at your rise
  140. Stiebel Eltron Tempra 36 Trend 36 kW Electric Tankless Water Heater36.0 kW · up to 0.8 GPM · about – GPM at your rise
  141. ThermoMate ET360 36 kW Electric Tankless Water Heater36.0 kW · up to 8.8 GPM · about – GPM at your rise
  142. WINTEMP WN36 Electric Tankless Water Heater36.0 kW · up to 8.7 GPM · about – GPM at your rise
  143. GEARPASS JSQ24 130,000 BTU Propane Tankless Water Heater130,000 BTU/h · up to 5.3 GPM · about – GPM at your rise
  144. LiberLive HKRV-WH01 130,000 BTU Natural Gas Outdoor Tankless Water Heater130,000 BTU/h · up to 5.3 GPM · about – GPM at your rise
  145. Ranein RHO13K-LPG 130,000 BTU Propane Outdoor Tankless Water Heater130,000 BTU/h · up to 5.3 GPM · about – GPM at your rise
  146. Ranein RHO13K-NG 130,000 BTU Natural Gas Outdoor Tankless Water Heater130,000 BTU/h · up to 5.3 GPM · about – GPM at your rise
  147. Rinnai RX130iN Condensing Tankless Water Heater130,000 BTU/h · up to 7.1 GPM · about – GPM at your rise
  148. VancEpic V-RH13K-LPG 130,000 BTU Propane Tankless Water Heater130,000 BTU/h · up to 5.3 GPM · about – GPM at your rise
  149. VancEpic V-RHO13K-NG 130,000 BTU Natural Gas Outdoor Tankless Water Heater130,000 BTU/h · up to 5.3 GPM · about – GPM at your rise
  150. APUS AP-AWH-Q20LPG 140,000 BTU Propane Tankless Water Heater140,000 BTU/h · up to 6.8 GPM · about – GPM at your rise
  151. APUS AP-AWH-Q20NG 140,000 BTU Natural Gas Tankless Water Heater140,000 BTU/h · up to 6.8 GPM · about – GPM at your rise
  152. Eccotemp 6.8GB-NG Natural Gas Outdoor Tankless Water Heater140,000 BTU/h · up to 6.8 GPM · about – GPM at your rise
  153. Rinnai RE140eN Natural Gas Tankless Water Heater140,000 BTU/h · up to 5.3 GPM · about – GPM at your rise
  154. Rinnai RE140iN Natural Gas Tankless Water Heater140,000 BTU/h · up to 5.3 GPM · about – GPM at your rise
  155. Rinnai RE140iP Propane Tankless Water Heater140,000 BTU/h · up to 5.3 GPM · about – GPM at your rise
  156. Camplux CA528 150,000 BTU Natural Gas Tankless Water Heater150,000 BTU/h · about – GPM at your rise
  157. Camplux CA528M-LP 150,000 BTU Propane Tankless Water Heater150,000 BTU/h · up to 6.4 GPM · about – GPM at your rise
  158. Camplux CA528M-NG 150,000 BTU Natural Gas Tankless Water Heater150,000 BTU/h · up to 6.4 GPM · about – GPM at your rise
  159. Camplux WA528 150,000 BTU Natural Gas Outdoor Tankless Water Heater150,000 BTU/h · up to 5.3 GPM · about – GPM at your rise
  160. Camplux WA528M-LP 150,000 BTU Propane Outdoor Tankless Water Heater150,000 BTU/h · up to 6.4 GPM · about – GPM at your rise
  161. Camplux WA528M-NG 150,000 BTU Natural Gas Outdoor Tankless Water Heater150,000 BTU/h · up to 6.4 GPM · about – GPM at your rise
  162. GASLAND C 150 150,000 BTU Natural Gas Tankless Water Heater150,000 BTU/h · up to 5.8 GPM · about – GPM at your rise
  163. GASLAND CE528NG 150,000 BTU Natural Gas Tankless Water Heater150,000 BTU/h · up to 5.8 GPM · about – GPM at your rise
  164. Rheem RTGH-84DVLN-3 157,000 BTU Natural Gas Condensing Tankless Water Heater157,000 BTU/h · up to 8.4 GPM · about – GPM at your rise
  165. Rheem RTG-70DVLN-3 160,000 BTU Natural Gas Tankless Water Heater160,000 BTU/h · up to 7.0 GPM · about – GPM at your rise
  166. Rheem RTG-70XLN-3 160,000 BTU Natural Gas Outdoor Tankless Water Heater160,000 BTU/h · up to 7.0 GPM · about – GPM at your rise
  167. Rinnai RE160iP Propane Tankless Water Heater160,000 BTU/h · up to 6.1 GPM · about – GPM at your rise
  168. Rinnai RXP160iN Condensing Tankless Water Heater160,000 BTU/h · up to 9.0 GPM · about – GPM at your rise
  169. FOGATTI FDG-CF170G-NG Natural Gas Tankless Water Heater170,000 BTU/h · up to 7.5 GPM · about – GPM at your rise
  170. Marey GA24CSALP 170,000 BTU Propane Tankless Water Heater170,000 BTU/h · about – GPM at your rise
  171. Eccotemp 7GB-NG Natural Gas Outdoor Tankless Water Heater180,000 BTU/h · up to 7.0 GPM · about – GPM at your rise
  172. MIZUDO HS180A0W-NG 180,000 BTU Natural Gas Outdoor Tankless Water Heater180,000 BTU/h · up to 8.1 GPM · about – GPM at your rise
  173. MIZUDO HW180A0W-NG 180,000 BTU Natural Gas Tankless Water Heater180,000 BTU/h · up to 7.9 GPM · about – GPM at your rise
  174. Rheem RTG-84DVLN-3 180,000 BTU Natural Gas Tankless Water Heater180,000 BTU/h · up to 8.4 GPM · about – GPM at your rise
  175. Rheem RTG-84XLP-3 180,000 BTU Propane Tankless Water Heater180,000 BTU/h · up to 8.4 GPM · about – GPM at your rise
  176. Rinnai RE180eN Natural Gas Tankless Water Heater180,000 BTU/h · up to 8.5 GPM · about – GPM at your rise
  177. Rinnai RE180iN Natural Gas Tankless Water Heater180,000 BTU/h · up to 8.5 GPM · about – GPM at your rise
  178. Rinnai RX180iN Condensing Tankless Water Heater180,000 BTU/h · up to 10.0 GPM · about – GPM at your rise
  179. Westinghouse HS180A0G-LP 180,000 BTU Propane Outdoor Tankless Water Heater180,000 BTU/h · up to 8.1 GPM · about – GPM at your rise
  180. Westinghouse HS180A0G-NG 180,000 BTU Outdoor Tankless Water Heater180,000 BTU/h · up to 8.1 GPM · about – GPM at your rise
  181. Westinghouse HW180A0G-LP 180,000 BTU Propane Tankless Water Heater180,000 BTU/h · up to 7.9 GPM · about – GPM at your rise
  182. Westinghouse HW180A0G-NG 180,000 BTU Tankless Water Heater180,000 BTU/h · up to 7.9 GPM · about – GPM at your rise
  183. APUS AP-AWH-W26LPG 190,000 BTU Propane Outdoor Tankless Water Heater190,000 BTU/h · up to 8.1 GPM · about – GPM at your rise
  184. APUS AP-AWH-W26NG 190,000 BTU Natural Gas Outdoor Tankless Water Heater190,000 BTU/h · up to 8.1 GPM · about – GPM at your rise
  185. Ranein RH19K-LPG 190,000 BTU Propane Tankless Water Heater190,000 BTU/h · up to 8.5 GPM · about – GPM at your rise
  186. Ranein RH19K-NG 190,000 BTU Natural Gas Tankless Water Heater190,000 BTU/h · up to 8.5 GPM · about – GPM at your rise
  187. Ranein RHO19K-LPG 190,000 BTU Propane Outdoor Tankless Water Heater190,000 BTU/h · up to 8.5 GPM · about – GPM at your rise
  188. Ranein RHO19K-NG 190,000 BTU Natural Gas Outdoor Tankless Water Heater190,000 BTU/h · up to 8.5 GPM · about – GPM at your rise
  189. VancEpic V-RH19K-NG 190,000 BTU Natural Gas Tankless Water Heater190,000 BTU/h · up to 8.5 GPM · about – GPM at your rise
  190. VancEpic V-RHO19K-NG 190,000 BTU Natural Gas Outdoor Tankless Water Heater190,000 BTU/h · up to 8.5 GPM · about – GPM at your rise
  191. A. O. Smith ATI-540P-N 199,000 BTU Natural Gas Tankless Water Heater199,000 BTU/h · up to 10.0 GPM · about – GPM at your rise
  192. Camplux WA686LP 199,000 BTU Propane Outdoor Tankless Water Heater199,000 BTU/h · up to 8.4 GPM · about – GPM at your rise
  193. Camplux WA686M-NG 199,000 BTU Natural Gas Outdoor Tankless Water Heater199,000 BTU/h · up to 8.4 GPM · about – GPM at your rise
  194. GASLAND CE686LP 199,000 BTU Propane Tankless Water Heater199,000 BTU/h · up to 7.6 GPM · about – GPM at your rise
  195. GASLAND CE686NG 199,000 BTU Natural Gas Tankless Water Heater199,000 BTU/h · up to 7.6 GPM · about – GPM at your rise
  196. GASLAND E 199 199,000 BTU Natural Gas Tankless Water Heater199,000 BTU/h · up to 7.6 GPM · about – GPM at your rise
  197. MIZUDO WCIU-HW199A1G-LP-M1n 199,000 BTU Propane Tankless Water Heater199,000 BTU/h · up to 10.3 GPM · about – GPM at your rise
  198. MIZUDO WCIU-HW199A1G-NG-M0 199,000 BTU Natural Gas Tankless Water Heater199,000 BTU/h · up to 10.3 GPM · about – GPM at your rise
  199. Rinnai CX199iN 199,000 BTU Condensing Tankless Water Heater199,000 BTU/h · up to 11.1 GPM · about – GPM at your rise
  200. Rinnai RE199eN Natural Gas Tankless Water Heater199,000 BTU/h · up to 9.8 GPM · about – GPM at your rise
  201. Rinnai RX199iN Condensing Tankless Water Heater199,000 BTU/h · up to 11.0 GPM · about – GPM at your rise
  202. ThermoMate CZ750NG Natural Gas Tankless Water Heater199,000 BTU/h · up to 8.0 GPM · about – GPM at your rise
  203. Rheem RTG-95DVELP-3 199,900 BTU Propane Tankless Water Heater199,900 BTU/h · up to 9.5 GPM · about – GPM at your rise
  204. Rheem RTG-95XLN-3 199,900 BTU Natural Gas Outdoor Tankless Water Heater199,900 BTU/h · up to 9.5 GPM · about – GPM at your rise
  205. Rheem RTG-95XLP-3 199,900 BTU Propane Outdoor Tankless Water Heater199,900 BTU/h · up to 9.5 GPM · about – GPM at your rise
  206. Rheem RTGH-95DVLN-3 199,900 BTU Natural Gas Condensing Tankless Water Heater199,900 BTU/h · up to 9.5 GPM · about – GPM at your rise
  207. Rheem RTGH-95DVLP-3 199,900 BTU Propane Tankless Water Heater199,900 BTU/h · up to 9.5 GPM · about – GPM at your rise
Full planner with your own fixtures and set point

Browse the grids

From the heater to the flush kit

Each category puts every unit we cover on one spec grid, with the maker's flow, input and install figures.

Ranein RH10K 100,000 BTU Natural Gas Tankless Water Heater134 productsGas Tankless Water HeatersCondensing, non-condensing, outdoor and propane units by BTU input, flow at your winter rise and venting.Rheem RTEX-18 Electric Tankless Water Heater106 productsElectric Tankless Water HeatersWhole-house and compact 240-volt units by kilowatts, amps and the breakers the maker calls for.Camplux ME10N 1.3-Gallon Mini-Tank Water Heater132 productsPoint-of-Use Water HeatersMini tanks and small tankless units for the sink that waits a minute for hot water.HYDRO MASTER 0560301 Tankless Isolation Valve Kit75 productsDescaling and Maintenance KitsFlush kits, descalers, isolation valves and recirculation pumps that keep a heater at full flow.Camplux VP70T Wall Thimble42 productsVenting and Install PartsVent kits and terminations, condensate neutralizers, gas connectors and install parts.

Planners

Work out flow, amps and gas load

The planners use the same maker figures as the unit pages and print every formula and input.

Tankless size planner

Fixtures at once and winter inlet water to the GPM you need, and the units that hold it.

Amps and gas load

kW to amps at 240 or 208 volts; BTU/h to cubic feet of gas or gallons of propane an hour.

Heat pump planner

Your busiest hour of hot water against a heat pump water heater's first-hour rating.

Most-reviewed units

Where most buyers start

Browse every category
Condensing gas tankless · Rinnai

Rinnai RX199iN Condensing Tankless Water Heater

199,000 BTU/h · 11.0 GPM max · Propane

Rinnai
Whole-house electric tankless · Rheem

Rheem RTEX-18 Electric Tankless Water Heater

18 kW · 240 V · 4.4 GPM max

Rheem
Non-condensing gas tankless · Ranein

Ranein RH10K 100,000 BTU Natural Gas Tankless Water Heater

100,000 BTU/h · 4.3 GPM max

Ranein
Mini-tank heater · Camplux

Camplux ME10N 1.3-Gallon Mini-Tank Water Heater

1.3 gal · 120 V

Camplux
Close-up of copper heat lines and braided hoses running across a dark equipment panel

Most tankless complaints are a sizing mistake: a unit picked by its maximum flow instead of by the fixtures and the January water it has to serve.

Know-how

Size it before you buy it

ElectricalCan an electric tankless water heater run a whole house?VentingCondensate neutralizers for tankless water heatersGasCondensing vs non-condensing tankless water heatersInstallDo you need an expansion tank with a tankless water heater?GasDoes a tankless water heater need a bigger gas line?SizingElectric tankless water heater for a showerCatalogAll know-how

Top units and versus

Sorted by a maker figure, never by price

Top unitsGas Tankless Water Heaters for Large HomesTop unitsCondensing Gas Tankless Water HeatersTop unitsNon-Condensing Gas Tankless Water HeatersTop unitsOutdoor Tankless Water HeatersTop unitsPropane Tankless Water HeatersTop unitsWhole-House Electric Tankless Water HeatersVersusStiebel Eltron Tempra 29 Plus vs Stiebel Eltron Tempra 29 Trend

How Tanklessly rates units

An installer's sizing sheet, not a review blog

The maker's numbers

Maximum flow, BTU input, kilowatts, voltage, breakers and venting come from each unit's own listing. Where a figure isn't stated, the page says so instead of guessing.

Flow at your rise

A box figure is measured at a small rise. Every unit page and the planner work out the flow at a 45°F and a 70°F rise from the unit's input, never above its stated maximum.

The install, up front

Amps, breakers, gas load and venting sit next to each unit so an electrician or gas fitter can confirm them before you buy. How we rate units.