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Rheem Tankless Hot Water with Culligan Water Filtration

header photo

tankless hot water for your attic or garage

pre-assembled tankless unit

replace (2) 50-gallon tanks with one rheem tankless

If your home has 2 to 3 full size bathrooms and (2) 50-gallon hot water tanks.

You will only need ONE

RTGH-95 Rheem Tankless/Culligan Hot Water Package with hot re-circulation


Closeup Look

Rheem Tankless with culligan filtration

  • Our Rheem tankless unit, with the Culligan water filtration, will last up to 20 years.

  • 70% of your home's water usage is hot waterWith the Rheem/Culligan system, 100% of your hot water usage will be filtered. 


All of your hot water is 100% filtered

that you can drink. 

  • The Culligan we uses a 3M, 5-micron filter ​with graded density carbon block that traps large particles on the surface and finer particles through the media depth for a long service life. Remember, average human red blood cell is about 5 microns.

  • This food grade quality filter is made of Polypropylene filtration media, this range of compact filters is able to enhance taste and reduce odor, chlorine, lead and controls the formation of scale.

  • Above is a cartridge comparison before and after 6 months
  • NSF/ANSI 42 & 372 Certification by WQA against NSF/ANSI42. The filter reduces up to 99% of Chlorine, sand, rust, sediment, scale color and odor. Lead Free Certified by WQA against NSF/ANSI372.

  • The cartridge can filter up to 100,000 gallons depending on local water quality. Suggest replacing it every 6- 12 months for the average household of 3 people, 3 showers. This is dependent on the city water supply quality.

The best filter cartridge is made by 3M. Also needed is silicone o-ring grease.

You can purchase them from the below links.

Culligan/3M filter cartridge -

Culligan O-Rings (replace every third cartridge) -

Filter cartridge o-ring grease -


How To Change Your Culligan Filter

tankless guru 5-year parts and labor warranty

Our exclusive 5-Year Parts and Labor Warranty covers the Rheem RTGH-tankless packages only. This warranty covers all components included and installed in the Rheem RTGH-tankless package, like the Rheem RTGH-tankless package, service valves, piping, venting, connectors and valves. Our warranty does not include the filter cartridge, it does cover the filter housing only if the filter cartridge is replaced by a Tankless Guru technician.

This warranty works in conjunction with Rheem tankless warranty. See link below for further information.

Note: The Rheem circulation system does not work in homes with tree and branch style plumbing design, which is found in about 1% of the homes.  

why we use water filtration

our water is drinkable

it's time

tankless guru rheem certification

BUILDZOOM Report    Link


  • A typical 50-gallon hot water tank heater, is only 38 to 50 percent efficient and will last only 8 to 10 years. Produces only 35 gallons of hot water.

  • Also, your hot water tank collects 8 to 10 lbs of sediment and toxins , which  you bathe in everyday and do not drink hot water from a tank heater...

This picture taken with a scope camera from inside a 7-year-old hot water tank heater.  You are looking at a buildup of calcium and other toxicants that you bathe in daily.

With our Rheem/Culligan tankless
hot water system
this will not happen. 

cost to replace two 50-gallon tanks

Typical cost to replace

(2) 50-gallon hot water tanks is

$2,450 to $2,950.


Battery Backup requirments

If you decide to purchase a Battery Back-Up, below specs. meets our requirements.

850VA/500W 120V, LCD Monitoring Screen, Standby Power, 8 Outlets, USB Charging, 3 Year Warranty, Uninterruptible Power Supply, Battery Backup with Surge Protection(PST5-850MT120)

Under normal conditions it will supply backup power to one Rheem tankless unit during home power failure. (note it will not run the circulation pump)

(1) It will give you 6 hours in standby mode. (tankless unit not being used)

(2) It will give you 1 hour of showering time.

(3) If the outside temperature dips below 30 degrees and your power goes out, in your home, the internal tankless heaters will activate. This UPS will supply enough power to protect the tankless unit for about 15-minute, that's enough time to shut down tankless unit and drain the water.


tankless guru