One of the most energy-efficient means of heating water today are indirect water heaters. These large tanks of water deliver hot water all year round. Once, these unit were large and clumsy and needed a lot of attention, but with the ever-increasing efficiency of modern technology, indirect water heaters are becoming more unobtrusive and reliable. Although, whenever one does break down you are reliant on a professional to come and fix them.
|HTP SSU45 SuperStor Ultra||45gal||39.25”x20”D||View on Amazon|
|Rheem MTS50200 Marathon||50gal||52.5”x23.5”D||View on Amazon|
|Burnham AL35SL Alliance||35gal||39.25”x20”D||View on Amazon|
|Weil-McLain 633500001 Aqua Plus Pewter||39.9gal||46¼”x21 7/8”D||View on Amazon|
|Crown MS2-50 Mega Stor||50gal||49¾”x23½”||View on Amazon|
|GMO Indirect Water Heater||40gal||59.68”x20.47”D||View on Amazon|
|Lochinvar EGS040||40gal||41.25”x22”D||View on Amazon|
|Amtrol HM-41Z||41gal||55”x22”D||View on Amazon|
|Triangle Tube SMART80 Phase IIIr||70gal||61”x46”D||View on Amazon|
|Dunkirk H2Oi40DK||40gal||44”x232.5”D||View on Amazon|
|HTP PH76-60 Phoenix||60gal||54.75”x23”D||View on Amazon|
|HTP RGH-75F||20gal||38.6”x21”||View on Amazon|
What we looked for in these systems is capacity, water pressure in GPH and size.
Here are 35-50 Gallon indirect water heaters
- Here are 35-50 Gallon indirect water heaters
- 1. HTP SSU45 SuperStor Ultra Stainless Steel Water Storage Tank 45 Gallons
- 2. Rheem MTS50200 Marathon 50–Gallon Tall Thermal Storage Tank
- 3. Burnham AL35SL Alliance SL Hydrastone-Lined Indirect-Fired Water Heater, 35 gal
- 4. Weil-McLain 633500001 Aqua Plus Pewter Indirect-Fired Water Heater, 39.9 gal
- 5. Crown MS2-50 Mega Stor Vertical Indirect Water Heater
- 6. GMO Indirect Water Heater 40 Gallon – Enamel – 1 Coil
- 7. Lochinvar EGS040 Double Wall Energy Saver Indirect Water Heater
- 8. Amtrol HM-41Z Top Down Boiler Mate
- 9. Triangle Tube SMART80 Phase III Indirect 70-Gallons Water Heater
- 10. Dunkirk H2Oi40DK 40 Gallon Indirect Water Heater
- 11. HTP PH76-60 Phoenix Light Duty High-Efficiency Stainless Steel Gas-Fired Water Heater
- 12. HTP RGH-75F High-Efficiency Crossover Hybrid Water Heater
This is the HTP Superstor 45-gallon single-coil model; it comes in a 316L stainless steel tank that resists corrosion. There are 4 Sizes Available, and all have the HTP high output finned, cupronickel heat Exchanger that comes with 11 Fins per inch.
Tank Capacity: 45 Gallons
Continuous Draw: 212 @ 141oF
The Marathon® thermal electric storage tanks were specifically designed for installation as a thermal storage tank and come with a backup electrical element that provides over 40 gallons of heated water. The unit also incorporates large water connections for lower pressure drops. This model uses a seamless, blow-molded, polybutene tank which is impervious to rust and corrosion.
Tank Capacity: 50 gallons
The Alliance SL uses a stone interior, what they call hydra stone. This lining absorbs water and then removes all the oxygen pockets over a short period of time, rendering the water inert. This retained water within the stone acts as both a heat barrier as well as an anti-corrosion protection.
Essentially what you get is a more efficient heat preservation process that saves on money, the large layer of high-density R-16 (hydra stone) insulation leads the system to lose less than 1oF per hour
Tank Capacity: 35 gallons
Continuous Draw: 162GHP @ 135oF
The Weil-McLain316L stainless steel tank is a single coil tank with the standard temperature and pressure relief valves and a thermostat connection already installed for fast wiring. These tanks have magnesium anodes installed, and all their wiring and connections are placed on the side for ease of access.
Tank Capacity: 39.9 Gallons
Continuous Draw: 335GPH @ 190oF
Dimensions: 46 ¼” x 21 7/8”D
The Mega-Stor II is a stainless-steel, indirect water heater that uses a Honeywell L4080B adjustable aquastat. This model comes with a removable inspection cap on the top and on the front which can be opened for viewing inside the tank and coil. It comes with a drain at the bottom for flushing sediment from the tank. The Mega-Stor tank is insulated with 2” polystyrene foam minimizing standby heat loss.
Tank Capacity: 50 gallons
Continuous Draw: 193GPH
The GMO one coil indirect water heater contains 40 Gallons in an enamel-coated container with 50 mm thickness of insulation. The heating element is made of a highly resistant Incoloy 840, and this unit incorporates the Emerson 59T66T thermostat with a Watts T/P Valve.
Tank Capacity: 40 gallons
Dimensions: 59.68” x 20.47”D.
Data Sheet PDF
The Lochinvar Energy Saver is an indirect-fired, potable water storage vessel. It comes with Non-CFC foam insulation covering the tank with a 2″ thick blanket of insulating foam. This non-CFC polyurethane closed-cell foam reduces standby losses of heat to the minimum, thereby maximizing heat retention.
This is a glass-lined steel tank; the glass lining is fused to the tank interior at 1600°F assuring lasting protection against rust and corrosion. The Anodes are aluminum, so they are naturally protected from electrolytic corrosion.
Tank Capacity: 40 gallons
Continuous Draw: 210GPH @ 140o
Dimensions: 41.25” x 22” D
Spec. sheet PDF
This is the Amtrol 41-gallon BoilerMax indirect water heating unit that is made of a steel outer shell with an internal Bimodal High-Density Polyethylene (HDPE) bottle. The insulation is a molded urethane over inner and outer shells. The heat exchanger is Finned Construction; Hi-Delta TBimodal HPDE Poly Bottle.
This brand provides twice the strength of traditional constructed models and is easy to install. It is also easily removable for cleaning and servicing.
Tank Capacity: 41 gallons
Continuous Draw: 173GPH
This double tank Stainless Steel Indirect Fired Water Heater is heated by the hot water from your boiler. This means that you heat your domestic water as your home is being heated as well. This model comes with a 2″ Polyurethane Foam insulation and heats up3 Times faster than conventional gas or electric water heaters. The heat exchange is also Self-cleaning and self-descaling.
Tank Capacity: 70 gallons
Continuous Draw: 400GPH
Dimensions: 61” x 46”D
Dunkirk’s H2O Stainless Steel Single Coil Indirect Water Heater is a 316L stainless steel constructed unit that holds 40 gallons of water. This model includes a stainless-steel dip tube and a thermoplastic jacket together with 2.25″ EPS Insulation that provides a maximum 0.5F° per hour standby loss.
Tank Capacity: 40 gallons
Continuous Draw: 166GPH @ 140oF
Dimensions: 44” x 232.5” D
The Phoenix Light Duty is Energy Star rated for operating at up to a .90 UEF. This unit is made of stainless steel with laser welded joints for extreme precision fabrication. This model comes with 2” PVC, CPVC or ULC S636 pipe and a combined vent length of 150 feet. HTP has in integrated an easy to read LCD (icon and text) display, and the unit provides a 3:1 turndown ratio of 25,000 to 76,000 Btuh.
Tank Capacity: 60 gallons
Continuous Draw: 140GPH
Dimensions: 54.75” x 23”D
This is the HTP natural gas cross-over indirect water heater that combines extra-thick insulation with small water volume storage. It also works in all altitudes and is certified to work up to 10,000’. The tank is stainless steel and comes with a recirculation system and has a NOx combustion system for better safety performance.
While this unit only has a 20-gallon tank, it’s built-in fire tube heat exchanger will heat the water up to 167-degree hot water, and then mixes the delivered temperature down through an ASSE 1017 mixing valve. This feature enables the unit to pour out 40-gallons at the same rate as a standard 50-gallon tank
Tank Capacity: 20 gallons
Continuous Draw: 107GPH
Dimensions: 38.6” x 21”
There are many types and models of indirect water tanks; the choice is not personal, it is technical and objective to the house requirements. Unless you are a water professional, we strongly urge you to consult with a water heating professional that can help you decide which of these 12 best indirect water tanks best suits your home water heating needs.