If you need an indirect hot water storage tank, first confirm that the product is designed to heat water through a separate boiler or heat source. The products listed here are mostly electric point-of-use heaters or water-storage tanks, not conventional boiler-connected indirect water heaters. The VEVOR 8-gallon model is best for under-sink hot water, while the ThermoMate 18-gallon model offers more electric storage capacity. The stainless pressure tank and RV tank serve different water-storage purposes and should not be treated as hot water heaters.
| Product | Best suited for | Important distinction |
|---|---|---|
| ThermoMate 18-Gallon Electric Heater | Small residential hot-water uses | Electric point-of-use heater, not a boiler coil tank |
| Portable 160L Stainless Pressure Tank | Pressurized water storage with a pump | Storage tank; heating function is not specified |
| VEVOR 6-Gallon Electric Heater | Small apartments, RVs, and supplementary hot water | Electric storage heater |
| VEVOR 8-Gallon Mini-Tank | Under-sink or nearby fixture hot water | Electric mini-tank |
| Akozon 10-Gallon RV Tank | Fresh-water storage in mobile settings | Water holding tank, not a water heater |
ThermoMate 18-Gallon Electric Water Heater
This ThermoMate model is an electric point-of-use water heater with an 18-gallon tank, 120-volt supply, 1,500-watt rating, and adjustable thermostat. Its capacity is larger than the 6- and 8-gallon mini-tanks in this list, making it a better fit where a small tank needs to serve more than one limited hot-water task.
Best for: Buyers seeking a compact electric hot-water source for residential washing or shower use. It was selected for its stated 18-gallon capacity and adjustable temperature control. Limitation: It is not described as an indirect tank and does not list a boiler heat exchanger. Verify installation requirements and available electrical service before choosing it.
Portable 160L Stainless Steel Pressure Tank
This 160-liter stainless steel tank is designed to connect to a pump. Its listed operation uses air pressure to supply water, with automatic pumping as the water level drops and stopping when the tank is full. The product description also notes food-grade stainless steel, a fully enclosed design, and an automatic pressure-release feature when pressure exceeds 0.35 MPa.
Best for: Buyers who need pressurized water storage as part of a pump system. It was selected as a large-capacity storage option, not as a hot-water appliance. Limitation: The product details do not specify a heating element or boiler coil. Do not assume that it can heat or store hot water safely; confirm the manufacturer’s temperature and system requirements.
VEVOR 6-Gallon Electric Tank Water Heater
This VEVOR unit is a 6-gallon, 1,600-watt electric storage heater with a 120-volt supply, LED display, knob control, and top outlet. Its listed uses include a studio apartment, RV, guest bathroom, or kitchen sink. The product description also identifies a 20 mm foam insulation layer, an enamel interior, and protections for dry heating, overheating, and overpressure.
Best for: A small, supplementary electric hot-water supply close to a fixture. The compact capacity and stated applications make it more suitable for modest, localized demand than a whole-house storage setup. Limitation: Six gallons may not meet prolonged or simultaneous hot-water demand. This is an electric heater, not an indirect boiler tank.
VEVOR 8-Gallon Electric Mini-Tank Heater
The VEVOR 8-gallon mini-tank uses a 1,440-watt heating element and includes a temperature-pressure safety valve. Its product information states that it can heat water to a maximum of 145°F and describes a stainless steel heater, corrosion-resistant inner tank, and polyurethane insulation. It is positioned for nearby hot-water needs such as cooking, dishwashing, and laundry.
Best for: Buyers who want more stored water than a 6-gallon unit provides, especially for a sink or nearby fixtures. It was selected for its 8-gallon capacity and stated safety valve. Limitation: The listing’s heating-time statement is not a guarantee of recovery under every installation or water condition. It is electric, not boiler-heated.
Akozon 10-Gallon RV Fresh-Water Tank
The Akozon tank is listed as a 10-gallon fresh-water holding tank for an RV, trailer, boat, or yacht. Its stated dimensions are 19.7 by 15.7 by 7.9 inches, and the product description identifies polyethylene construction and heat- and cold-related use. It is included as a mobile water-storage option, not as a hot-water heater.
Best for: Buyers seeking a fresh-water holding tank for a mobile or marine setup. It was selected because its stated capacity and intended settings are clear. Limitation: The listing does not describe a heating system, boiler connection, or temperature-pressure relief valve. Do not use it as an indirect hot water storage tank without explicit manufacturer approval.
Buying Guide: How to Choose an Indirect Hot Water Storage Tank
A true indirect water heater stores domestic hot water and uses heat transferred from a separate source, commonly through an internal heat exchanger connected to a boiler. The heat source does not directly mix with the household water. By contrast, the electric models above heat water inside their own tanks, while the pressure and RV tanks are storage vessels without a specified heating method.
Do you need a true indirect tank or an electric point-of-use heater?
Choose an indirect model when you have a compatible boiler-based heating system and want the boiler to heat stored domestic water. Look for manufacturer documentation that identifies the heat-exchanger coil, boiler connections, tank capacity, and approved operating conditions. Choose an electric point-of-use heater when the goal is a small, local hot-water supply and an electrical connection is appropriate.
How much hot-water capacity do you need?
Estimate demand by considering how many fixtures may draw hot water at once and how long they run. A 6- or 8-gallon mini-tank is intended for limited, nearby uses; it is not automatically a whole-house replacement. The 18-gallon ThermoMate offers more storage among the listed electric heaters, but capacity alone does not determine recovery speed or suitability for a household.
What heat source and connections should you verify?
For an indirect tank, confirm that the tank and boiler can be connected according to their specifications. Check the required water, boiler, and electrical connections, if any, along with available installation space. A product described only as a pressure tank or fresh-water container is not evidence of a heating connection. Ask a qualified installer to verify the proposed system.
Which safety and insulation details matter?
Review the specified temperature-pressure relief provisions, operating pressure, insulation, and installation instructions. The VEVOR electric models list safety features, but that does not establish that they are suitable for a boiler loop. A pressure tank’s automatic pressure release is not a substitute for confirming the safety equipment required for a hot-water system.
Can a regular storage tank replace an indirect water heater?
Not necessarily. A storage vessel may hold water without having a heat exchanger or being rated for the temperatures and pressures in a heating system. Confirm the intended application and manufacturer specifications before connecting any tank to a boiler, pump, or domestic hot-water line.
Frequently Asked Questions
What is an indirect hot water storage tank?
It is a tank that stores household hot water and receives heat from a separate source, typically through a heat exchanger. The boiler water and household water remain separate.
Are electric mini-tank heaters indirect water heaters?
No. The ThermoMate and VEVOR models listed here use electric heating elements. They are point-of-use or storage water heaters, not boiler-connected indirect tanks.
Can a stainless pressure tank heat water?
The listed 160-liter stainless tank is described as a pump-connected pressure storage tank. Its provided features do not specify a heater or heat exchanger, so it should not be assumed to heat water.
Is a larger tank always better?
No. A larger capacity can provide more stored water, but the right choice also depends on demand, recovery, heat source, installation space, and system compatibility.
What should I check before buying an indirect tank?
Confirm the tank is explicitly designed for indirect heating, then check its capacity, heat-exchanger details, rated pressure and temperature, connections, installation requirements, and compatibility with the boiler.