Rheem 400L Electric Hot Water System Review

The Rheem 400L Electric Hot Water System is a large-capacity electric storage option for buyers replacing an older high-volume tank, comparing supply-only hot water systems online, or looking for a recognised Australian brand from the Rheem Hot Water Systems range.

If you are comparing large electric storage replacements, it is also worth checking the full Electric Hot Water Systems collection and confirming whether you need extra parts from Valves, Pipework and Fittings before checkout.

Quick Answer

The Rheem 400L Electric Hot Water System may suit larger families, shared homes, rental properties, high-use households and replacement jobs where a 250L or 315L electric storage system may not provide enough stored hot water.

It is a 400L electric storage water heater from Rheem’s 491 / 492 Series range. The product page lists the 491400 single element model and the 492400 twin element model, with the supplied product link focused on the 3.6kW single element option.

It may be a good option if you need a large stored hot water volume, have suitable space and access, and already have a licensed plumber and electrician arranged.

It may not be the right choice if your household has low to moderate hot water use, access is tight, your electrical setup is unsuitable, or you want to compare lower running cost options such as heat pump hot water.

Product Snapshot

Who This Product May Suit

The Rheem 400L may suit buyers who need one of the larger residential electric storage hot water options.

It may suit:

• Existing 400L electric hot water system replacements

• Larger family homes

• Shared homes

• Busy households

• Larger rental properties

• Investment properties

• Homes with high shower demand

• Homes with bath use

• Properties without gas connected

• Buyers wanting a large stored hot water volume

• Buyers who want single element or twin element model options

• Homes with suitable installation space and access

• Supply-only customers who already have licensed trades arranged

A 400L electric storage system is generally chosen when stored capacity is the main priority.

Who Should Compare Other Options

A 400L electric hot water system is not the right fit for every home. It is a large tank, so the site and actual household demand matter.

You should compare other options if:

• Your household has low or moderate hot water use

• Your old 250L or 315L system already supplied enough hot water

• You only need hot water for a granny flat, unit or low-use area

• You have limited space for a large tank

• Access is tight, steep, raised or difficult

• Your electrical circuit does not suit the selected model

• You want lower running costs and are considering a heat pump

• You have solar power and want to shift more hot water heating into daylight hours

• You need faster recovery rather than only more stored capacity

• The system is being relocated

• Existing valves, drainage, safe tray, base or pipework need major upgrades

For energy-efficiency comparisons, check Heat Pump Hot Water Systems. For smaller electric storage systems, compare the full Electric Hot Water Systems range.

Rheem 400L Features That Matter

The Rheem 400L is a large electric storage unit, but several product details are worth checking before ordering.

400L Hot Water Delivery

The 400L capacity may suit larger homes, shared households and high-use properties where several showers, laundry use and kitchen hot water demand can happen close together.

It may be excessive for smaller households, so sizing should be checked against actual use.

Rheem 491 / 492 Series

The Rheem 400L is part of the Rheem 491 / 492 Series electric storage range.

The product page lists:

• 491400 single element model

• 492400 twin element model

The correct option depends on the property’s electrical setup, tariff arrangement and hot water demand.

Single Element and Twin Element Options

A single element model is commonly used for standard electric storage replacement.

A twin element model may suit homes needing faster heating or extra daytime hot water support where the electrical setup and tariff arrangement allow it.

Before ordering, confirm the model and element requirements with a licensed electrician.

Rheem Ultranamel® Cylinder Coating

The Rheem 400L uses Rheem Ultranamel® cylinder coating.

Cylinder life still depends on correct selection, compliant installation, pressure control, valve setup, water quality and servicing conditions.

Thicker Sacrificial Anode

The product page lists a thicker sacrificial anode for additional cylinder protection.

Anodes are part of the cylinder protection system, but water quality and maintenance conditions still matter.

Dual-Handed Connections

The Rheem 400L includes dual-handed inlet and outlet fittings.

This may help with replacement flexibility where existing pipework comes from different sides, but the installer still needs to check connection positions, valve layout, drainage and clearances.

Lower-Cost Tariff Suitability

The Rheem 400L range is listed as suitable for connection to lower-cost tariffs where available and appropriate.

The best tariff setup depends on the selected model, electricity plan, household demand, recovery requirements and installation setup.

Rheem 400L vs Other Electric Tank Sizes

The Rheem 400L may suit buyers who have outgrown 315L or are replacing an existing 400L electric tank.

Rheem 400L vs Heat Pump Hot Water

The Rheem 400L electric storage system uses an electric element to heat stored water.

A Heat Pump Hot Water System uses heat from the surrounding air to heat stored water more efficiently under suitable conditions.

The Rheem 400L may suit buyers who want a straightforward large electric storage replacement. A heat pump may suit buyers prioritising running cost reduction, solar power use, outdoor airflow suitability and energy efficiency.

The right choice depends on:

• Existing system type

• Household hot water demand

• Available outdoor space

• Airflow

• Noise placement

• Drainage

• Electrical setup

• Budget

• Installer advice

Price and Value: What Buyers Should Check

The online price can change depending on stock, sale pricing, selected variant, delivery area and checkout options.

Before ordering, check:

• Current product price

• Selected model

• Selected element rating

• Whether single element or twin element is required

• Delivery cost shown at checkout

• Delivery timeframe for your postcode

• Whether valves are added separately

• Whether copper, fittings or insulation are required

• Whether a support base is required

• Whether a safe tray is required for indoor installation

• Whether old system removal is arranged separately

• Whether disposal is arranged separately

• Whether installation quote help is being requested separately

• Whether your licensed installer has confirmed the system is suitable

The supply-only price is not the total installed cost.

What to Check Before Ordering

Before buying the Rheem 400L Electric Hot Water System, confirm the details below.

1. Existing Tank Size

Check the label on the old hot water system.

If you are replacing an existing 400L electric tank and the household still needs that capacity, another 400L system may be suitable.

If the old 400L tank was oversized, compare 315L or 250L options.

If the old 315L tank regularly ran out, the Rheem 400L may be worth comparing.

2. Single Element or Twin Element

The product page lists the Rheem 491400 as the single element model and 492400 as the twin element model.

A twin element model may suit some homes that need faster recovery or extra daytime hot water support, but only where the electrical setup and tariff arrangement are suitable.

Confirm this before ordering.

3. Electrical Suitability

Your electrician should confirm:

• Existing circuit size

• Breaker rating

• Cable size

• Isolator condition

• Tariff setup

• Switchboard suitability

• Whether the selected model is suitable

• Whether any electrical upgrades are required

Electrical connection, disconnection, wiring, testing, element changeover or modification must be carried out by a suitably licensed electrician.

4. Indoor or Outdoor Location

The Rheem 400L may suit indoor or outdoor installation where compliant.

For indoor locations, check:

• Safe tray requirements

• Drainage

• Leak protection

• Doorway clearance

• Ceiling height

• Cupboard clearance

• Floor support

• Service access

• Overflow discharge

For outdoor locations, check:

• Stable support base

• Weather exposure

• Pipe insulation

• Electrical protection

• Access around the unit

• Relief drain discharge location

• Future service and replacement access

5. Dimensions and Access

The product page lists the Rheem 400L at approximately 1840mm high and 690mm diameter, with a packaged weight of approximately 120kg.

Before checkout, confirm:

• Gate width

• Side access

• Stairs

• Slopes

• Retaining walls

• Tight corners

• Garage access

• Apartment access

• Laundry or cupboard space

• Platform height

• Existing base size

• Delivery drop-off location

• Whether the unit can be safely moved into position

Restricted access may affect delivery, handling and installer costs.

6. Water Pressure and Valves

The product page lists:

• 1000kPa relief valve pressure

• 850kPa expansion control valve setting

• 680kPa maximum water supply pressure with ECV

• 800kPa maximum water supply pressure without ECV

Your plumber should confirm pressure control requirements before installation.

Do not assume the old valves are suitable just because they were connected to the previous tank.

7. Valves, Fittings and Accessories

A large electric storage replacement may require more than the hot water system itself.

Your plumber may need to check or supply:

• Tempering valve

• PTR valve

• Expansion control valve

• Pressure limiting valve

• Duo valve

• Isolation valve

• Non-return valve

• Copper pipework

• Brass fittings

• Crimp fittings

• Pipe insulation

• Concrete support base

• Plastic support base

• Safe tray

• Sealants and sundries

Compare required parts in Valves, Pipework and Fittings.

8. Delivery Timing

Delivery availability can depend on postcode, stock, product size, order time, carrier availability and checkout options.

Before ordering, confirm:

• Delivery area

• Delivery cost

• Expected delivery timeframe

• Whether someone can receive the unit

• Delivery drop-off access

• Whether the installer wants the system delivered before or on the installation day

A 400L tank is a large delivery item, so access should be checked before checkout.

Supply-Only Pricing Reminder

Hot Water Outlet sells the Rheem 400L as a supply-only product.

Supply-only pricing usually does not include:

• Installation

• Plumbing labour

• Electrical work

• Old unit removal

• Disposal

• Valves

• Fittings

• Pipework changes

• Drainage work

• Switchboard upgrades

• Circuit upgrades

• Compliance upgrades

• Safe trays

• Concrete bases or platforms

• Delivery beyond what is shown at checkout

Plumbing work must be completed by a licensed plumber. Electrical work must be completed or checked by a licensed electrician.

Hot Water Outlet does not directly install hot water systems. Where available, Hot Water Outlet may help request installation quotes from reputable licensed installers, but installation is quoted and arranged separately with the installer.

Product Alternatives to Compare

Before ordering the Rheem 400L, compare:

• Other Rheem Hot Water Systems

• The full Electric Hot Water Systems range

• Heat Pump Hot Water Systems if energy efficiency is a priority

• Valves, Pipework and Fittings if valves, bases, copper or connection parts are needed

A Rheem 400L electric storage system can be a strong match for large homes and high-use properties, but suitability still depends on household demand, circuit suitability, water pressure, access, drainage and existing compliance.

Common Buying Mistakes

Avoid these mistakes when buying the Rheem 400L online:

• Buying a 400L tank without checking actual household demand

• Assuming the largest tank is always the best choice

• Not checking whether single element or twin element is required

• Not confirming the selected electrical setup

• Assuming old valves can be reused

• Forgetting pressure control requirements

• Forgetting safe tray or drainage requirements

• Not checking delivery access

• Not measuring the installation space

• Ignoring old system removal and disposal

• Assuming supply-only price equals installed price

• Choosing 400L when a heat pump may suit better

• Ordering before a licensed plumber or electrician confirms suitability

Buyer Checklist

Before checkout, confirm:

• Existing system capacity

• Existing brand and model

• Whether 400L is the right size

• Number of people in the home

• Number of bathrooms

• Shower habits and flow rates

• Bath usage

• Single or twin element requirement

• Electrical circuit suitability

• Tariff setup

• Indoor or outdoor location

• Tank dimensions

• Delivery access

• Base or safe tray requirements

• Drainage requirements

• Water pressure

• Valve requirements

• Pipework and fitting requirements

• Old system removal plan

• Disposal plan

• Licensed plumber and electrician availability

FAQs

Is the Rheem 400L good for large families?

It may suit larger families, shared homes and high-use households, depending on shower length, number of bathrooms, bath use, flow rates, tariff setup, climate and daily hot water habits.

What model is the Rheem 400L electric hot water system?

The product page lists the Rheem 491400 as the single element model and 492400 as the twin element model.

Is the supplied product link single element?

Yes. The supplied link is for the 3.6kW single element option.

Is there a twin element Rheem 400L model?

Yes. The Rheem 492400 is listed as the twin element model. It may suit homes needing faster heating or extra daytime hot water support where the electrical setup and tariff arrangement are suitable.

How many people does the Rheem 400L suit?

Rheem lists the 400L model as suitable for 8–9 people under stated usage assumptions. Actual suitability depends on shower length, hot water use, tariff setup, climate and household habits.

Can the Rheem 400L be installed outside?

Yes. It is listed for indoor or outdoor installation where the location is compliant and suitable.

Can the Rheem 400L be installed inside?

Yes. It may be installed inside where compliant. Indoor installations may require a safe tray, drainage, leak protection, suitable clearances and proper access.

What are the dimensions?

The product page lists the Rheem 400L at approximately 1840mm high and 690mm diameter.

What is the relief valve pressure?

The Rheem 400L is listed with a 1000kPa relief valve pressure.

What is the expansion control valve setting?

The Rheem 400L is listed with an 850kPa expansion control valve setting.

Does the Rheem 400L include valves?

Do not assume valves are included unless clearly selected. Your plumber should confirm whether a valve kit, tempering valve, expansion control valve, pressure limiting valve or other fittings are required.

Do I need a plumber and electrician?

Yes. Plumbing work must be completed by a licensed plumber, and electrical work must be completed or checked by a licensed electrician.

Does Hot Water Outlet install the Rheem 400L?

No. Hot Water Outlet sells supply-only hot water systems and accessories online. Where available, Hot Water Outlet may help request installation quotes from reputable licensed installers, but installation is quoted and arranged separately.

Is supply-only pricing the same as installed pricing?

No. Supply-only pricing is for the product itself. It usually does not include installation, electrical work, valves, pipework changes, old system removal, disposal, drainage or compliance upgrades.

Should I buy a 400L electric system or a heat pump?

A 400L electric system may suit buyers who want large stored capacity and a straightforward electric storage replacement. A heat pump may suit buyers who are prioritising energy efficiency and have suitable outdoor airflow, drainage, electrical setup and noise placement.

Final CTA

Buy the Rheem 400L Electric Hot Water System online from Hot Water Outlet, or compare more options in Rheem Hot Water Systems and Electric Hot Water Systems.

Before checkout, confirm the tank size, selected model, electrical suitability, installation location, delivery access, pressure requirements and any required parts from Valves, Pipework and Fittings.