Tankless Water Heaters what size do you need?
This page will give you a quick-view look at all our Tankless Gas Water Heaters
and electric water heaters. What size for your needs?
For more detailed information - please review each hot water heater's detailed information
pages and on-line manuals.
Bosch AquaStar 1600PS - Standing Pilot - Solar Booster or as Stand-Alone heater - Gravity Vent
Takagi T-KJr - Electronic Ignition - Optional Direct Vent - Horizontal or Vertical Power Vented
Bosch AquaStar 1600P / 1600H gas tankless water heaters will give you a max output of 4 GPM.
A 50-degree water input and a 55-degree temperature rise will give you
3.3 gpm. This is enough for a standard shower (2.5 gpm) and
maybe a small sink at the same time. More info on Bosch 1600 Series Tankless Water Heaters ... click here
Takagi T-KJr tankless water heater will give you about 4 GPM with 50-degree
water input and a 55-degree temperature rise. This is enough for one
standard shower (2.5 gpm) and a small sink at the same time. The Takagi T-KJr can
also be used for heating applications up to 180 degrees.
More info on the Takagi Tankless Water Heater ... click here
Two major uses A single standard use is considered to be 2.5 gallons per minute (GPM)
click for more info
Bosch AquaStar 2400ES - Electronic Ignition - Direct Vent - Horizontal or Vertical Venting
Bosch AquaStar 2700ES - Electronic Ignition - Direct Vent - Horizontal or Vertical Venting
Takagi T-K3 - Electronic Ignition - Horizontal or Vertical Power Vented - Optional Direct Vent
Takagi T-M32 - Electronic Ignition - Horizontal or Vertical Power Vented
Bosch AquaStar 2400ES Tankless Water Heater will give you a max output of 6.35 GPM.
A 50-degree water input and a 55-degree temperature rise will give you 5.3 gpm. Direct
Vented (Sealed Combustion). (The Bosch 2400ES has replaced the Bosch 2400E)
Enough hot water for two standard showers (2.5 gpm each). With optional Bosch AquaStar Outdoor Installation Kit - AQOK
- this unit can be installed outside in warmer areas.
More info on the Bosch Aquastar 2400ES Tankless Water Heater ... click here
Bosch AquaStar 2700ES Tankless Water Heater will give you a max output of 7.15 GPM.
A 50-degree water input and a 55-degree temperature rise will give you 5.9 gpm. Direct
Vented (Sealed Combustion). With optional Bosch AquaStar Outdoor Installation Kit - AQOK - this
unit can be installed outside in warmer areas.
Enough hot water for two standard showers and a bathroom sink too. (2.5 gpm each).
More info on the Bosch Aquastar 2700ES Tankless Water Heater ... click here
Takagi T-K3 Tankless Hot Water Heater will give you a max output of 6.9 GPM.
A 50-degree water input and a 55-degree temperature rise will give you about 6 GPM. This is enough for two
standard showers (2.5 gpm each). The Takagi T-K3 can also be used for heating applications up to 180 degrees.
More info on the Takagi TK3 Tankless Water Heater ... click here
Takagi T-M32 Tankless Hot Water Heater will give you a max output of 9.6 GPM.
A 50-degree water input and a 55-degree temperature rise will give you about 7 GPM. This is enough for two
standard showers (2.5 gpm each) and a sink at the same time. In warmer climits with
input water at about 60-degrees - you should be able to run 3 single-shower head showers
at one time. The Takagi T-M32 can also be used for heating applications up to 180 degrees.
More info on the Takagi T-M32 Tankless Water Heater ... click here
Three major uses or more A single standard use is considered to be 2.5 gallons per minute (GPM)
click for more info
Takagi T-M32- Electronic Ignition - Horizontal or Vertical Power Vented
Any of the Takagi Water heaters with used in conjuction with a storage tank
Takagi T-M32 Tankless Water Heater will give you a max output of 9.6 GPM. For Warmer Areas - use
a 60-degree water input and a 45-degree temperature rise will give you about 8 GPM. This is enough for three
standard showers (2.5 gpm each) at the same time.
More info on the Takagi T-M32 Tankless Water Heater ... click here
Bosch AquaStar 2700ES Tankless Water Heater will give you a max output of 7.15 GPM.
For Warmer Areas - use a 60-degree water input and a 45-degree temperature rise will give you 7.15 gpm.
This can provide up to 3 showers are once, but you may have to use low
More info on the Bosch Aquastar 2700ES Tankless Water Heater ... click here
For Warmer Areas - use
Specialty Uses
Bosch 1000P Gas Tankless Water Heaters
Bosch AquaStar 1000P Tankless Hot Water Heater will give you about 1 GPM with a 50-degree water input
and 55-degree rise. The 1000P should not be used for showers. More info...
One major use A single Standard use is considered to be 2.5 gallons per minute (GPM))
click for more info
PowerStar AE 115 - Electric Tankless Water Heater
PowerStar AE 125 - Electric Tankless Water Heater
Stiebel Eltron Tempra 20 - Electric Tankless Water Heater
Stiebel Eltron Tempra 24 - Electric Tankless Water Heater
Stiebel Eltron Tempra 29 - Electric Tankless Water Heater
Stiebel Eltron Tempra 36 - Electric Tankless Water Heater
PowerStar AE 115 Electric Tankless Water Heater with a 50-degree water input and a 55-degree temperature rise will give you about 2.4 gpm. This is enough for a standard shower (2.5 gpm) where
ground water is warmer than 55 degrees year-round. (80 amps - requires min 150 amp service)
More info on PowerStar AE 115 Electric Tankless Water Heaters ... click here
PowerStar AE 125 Electric Tankless Water Heater with a 50-degree water input and a 55-degree temperature
rise will give you about 3.4 gpm. This is enough for a standard shower (2.5 gpm) and
maybe a small sink at the same time. (120 amps - requires min 200 amp service)
More info on PowerStar AE 125 Electric Tankless Water Heaters ... click here
Stiebel Eltron Tempra 20 Electric Tankless Water Heater with a 50-degree water input and a 55-degree temperature
rise will give you about 2.3 gpm. This is enough for a standard shower (2.5 gpm) in warm climates.
(80 amps - requires min 150 amp service) More info Stiebel Tempra 20 Electric Tankless Water Heaters ... click here
Stiebel Eltron Tempra 24 Electric Tankless Water Heater with a 50-degree water input and a 55-degree temperature
rise will give you about 2.9 gpm. This is enough for a standard shower (2.5 gpm)
(80 amps - requires min 160 amp service) More info Stiebel Tempra 24 Electric Tankless Water Heaters ... click here
Stiebel Eltron Tempra 29 Electric Tankless Water Heater with a 50-degree water input and a 55-degree temperature
rise will give you about 3.6 gpm. This is enough for a standard shower (2.5 gpm) and
maybe a small sink at the same time. (120 amps - requires min 200 amp service)
More info Stiebel Tempra 29 Electric Tankless Water Heaters ... click here
Stiebel Eltron Tempra 36 Electric Tankless Water Heater with a 50-degree water input and a 55-degree temperature
rise will give you about 4.5 gpm. This is enough for a standard shower (2.5 gpm) and
maybe a small sink at the same time. Possible 2 showers at the same time in warm climates.
(120 amps - requires min 300 amp service)
More info Stiebel Tempra 36 Electric Tankless Water Heaters ... click here
Specialty Uses
Powerstar Point-of-Use AE.3.4, AE7.2, AE9.5 and AE12
Please note: These numbers may not reflect your appliances or fixtures due to
differences in water pressure from location to location. Differences are also
due to efficiency of appliances and fixtures.
If you have a multi shower head system - you need to find out how much water all the
shower heads will consume per minute. Make sure the tankless water heater you use will
provide the correct amount of hot water. If you don't see one - contact us and we will
advise you how to use a tankless water heater with a multi-shower head system.
One last thing: We are assuming that your input water (ground) is 50-degrees. Your
actual input water may be slightly colder (not likely) or very much warmer (likely in warm climates).
You should check and review your input water temperature before relying on any of the above numbers.
If your ground water is colder - then you will get less output - if your ground water is
warmer - then you will get more output.
Average ground water in the USA is between 50 and 55-degrees winter to summer.
