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forum threadIzzy138 | Staff posted Jan 20, 2026 05:27 PM
forum threadIzzy138 | Staff posted Jan 20, 2026 05:27 PM

27kW ThermoMate Tankless Electric On Demand Instant Hot Water Heater $369.99 + Free Shipping

$370

$470

21% off
ThermoMate
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ThermoMate [thermomate.com]has the 27kW ThermoMate Tankless Electric On Demand Instant Hot Water Heater for $429.99 - $60 w/code THSDET270 = $369.99. Shipping is Free

Details:

  • Instant Unlimited Hot Water: Require 3 SET x Double-pole 40AMP Breakers to Achieve 240V for this On-demand tankless electric water heater, providing hot water in 3 seconds when you need it and as long as you need. Flow Rate 5.27GPM @35°F Rise.
  • Self-modulating Powe: Self-modulating technology regulates the amount of energy required to heat water only when you need it with 99.8% efficiency, saving up to 60% on water heating costs compared to the traditional tank water heater. Wall-mounted compact size with no water tank, convenient for any space, saving floor space and fitting into tight
  • Stable Water Temperature: Auto-adjusting energy consumption based on income water temperature and flow, ensuring maximum efficiency, continuous stable temperature, and optimal power usage. Digital temperature display allowing adjustment in 1° increment from 80°F to 140°F. Heating elements separated from water tubes significantly reduce scale, corrosion, and mineral buildup on the element, achieving better performance and low maintenance.
  • Easy Installation & Safety Protection: ETL certified with overheating protection, auto stop heating when detecting no water, and quality workmanship for leakage protection.
  • 【NOTE】Make sure this water heater is the correct size for your hot water need: 27kW at 240V draw max 114Amp; Required breaker 3 x Double-POLE 40AMP; Wire gauge 3 x 8AWG; Unit size 17.12" x 13.12" x 3.12"; Water connection 3/4" NPT. 2-year limit warranty and 24/7 customer support services.
    • Power• ON/OFF Dial Control with adjustable digital temperature display•
    • Self-modulating power control• 27kW Model Flow Rate: up to 6.38 GPM
    • ApplicationsWater-Saver Shower Head – 1.5 GPM• Standard Shower Head – 2.0 GPM•
    • Standard Hand Sink – 0.5 GPM• Kitchen Sink – 1 to 2 GPM• Bath Tub – 4 GPM• Dishwasher – 1 to 2 GPM• Washing Machine – 1 to 1.5 GPM•
    • Average Gallons Per Minute (GPM) based on 2010 Plumbing Standards
    • Packing List• 1 x ET270• 1 x Mounting Kits
Community Notes
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Deal Details
Community Notes
About the Poster
ThermoMate [thermomate.com]has the 27kW ThermoMate Tankless Electric On Demand Instant Hot Water Heater for $429.99 - $60 w/code THSDET270 = $369.99. Shipping is Free

Details:

  • Instant Unlimited Hot Water: Require 3 SET x Double-pole 40AMP Breakers to Achieve 240V for this On-demand tankless electric water heater, providing hot water in 3 seconds when you need it and as long as you need. Flow Rate 5.27GPM @35°F Rise.
  • Self-modulating Powe: Self-modulating technology regulates the amount of energy required to heat water only when you need it with 99.8% efficiency, saving up to 60% on water heating costs compared to the traditional tank water heater. Wall-mounted compact size with no water tank, convenient for any space, saving floor space and fitting into tight
  • Stable Water Temperature: Auto-adjusting energy consumption based on income water temperature and flow, ensuring maximum efficiency, continuous stable temperature, and optimal power usage. Digital temperature display allowing adjustment in 1° increment from 80°F to 140°F. Heating elements separated from water tubes significantly reduce scale, corrosion, and mineral buildup on the element, achieving better performance and low maintenance.
  • Easy Installation & Safety Protection: ETL certified with overheating protection, auto stop heating when detecting no water, and quality workmanship for leakage protection.
  • 【NOTE】Make sure this water heater is the correct size for your hot water need: 27kW at 240V draw max 114Amp; Required breaker 3 x Double-POLE 40AMP; Wire gauge 3 x 8AWG; Unit size 17.12" x 13.12" x 3.12"; Water connection 3/4" NPT. 2-year limit warranty and 24/7 customer support services.
    • Power• ON/OFF Dial Control with adjustable digital temperature display•
    • Self-modulating power control• 27kW Model Flow Rate: up to 6.38 GPM
    • ApplicationsWater-Saver Shower Head – 1.5 GPM• Standard Shower Head – 2.0 GPM•
    • Standard Hand Sink – 0.5 GPM• Kitchen Sink – 1 to 2 GPM• Bath Tub – 4 GPM• Dishwasher – 1 to 2 GPM• Washing Machine – 1 to 1.5 GPM•
    • Average Gallons Per Minute (GPM) based on 2010 Plumbing Standards
    • Packing List• 1 x ET270• 1 x Mounting Kits

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Jan 20, 2026 06:12 PM
43 Posts
Joined Aug 2016
Hawkeye3636Jan 20, 2026 06:12 PM
43 Posts
Any experiences with this one?
Jan 21, 2026 01:43 AM
2,931 Posts
Joined Mar 2008
produkeJan 21, 2026 01:43 AM
2,931 Posts
New to this. 3 x 40amp breaker is more than half capacity on my main electric panel. That's a lot of juice, no?
Jan 24, 2026 08:25 AM
408 Posts
Joined Mar 2011
PBougeJan 24, 2026 08:25 AM
408 Posts
3x double pole 40a breaker? Jesus you're going to need a 400 amp panel upgrade with this bad boy haha. I wouldn't even consider this unless you have at least a 200amp panel and the rest of your appliances are on gas and you don't have an electric vehicle. But at that point you're better off getting a gas water heater or hybrid.
Last edited by PBouge January 24, 2026 at 01:28 AM.
Jan 24, 2026 05:14 PM
3,437 Posts
Joined Sep 2006
GiantcrazyJan 24, 2026 05:14 PM
3,437 Posts
Quote from PBouge :
3x double pole 40a breaker? Jesus you're going to need a 400 amp panel upgrade with this bad boy haha. I wouldn't even consider this unless you have at least a 200amp panel and the rest of your appliances are on gas and you don't have an electric vehicle. But at that point you're better off getting a gas water heater or hybrid.
With 200A service you'd likely just be under the wire, but cutting it close, even with all three. This thing is a power hog, but it's meant to be a large supply of instant on hot water, not really a replacement for a gas or heat pump hot water heater.
1
Jan 25, 2026 07:30 AM
408 Posts
Joined Mar 2011
PBougeJan 25, 2026 07:30 AM
408 Posts
Quote from Giantcrazy :
With 200A service you'd likely just be under the wire, but cutting it close, even with all three. This thing is a power hog, but it's meant to be a large supply of instant on hot water, not really a replacement for a gas or heat pump hot water heater.
Actually this does replace water heaters often but you can use them together so you don't have to wait for the tank to heat back up. That's why this is over 5gpm. Most individual insta hot water heaters I typically install are usually only 20 - 40a 2 pole for a single fixture. These type are more common in commercial settings like office bathrooms and breakrooms.

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