Rheem MPi-325 Series II Heat Pump Hot Water System

The Rheem MPi-325 Series II Heat Pump Hot Water System is available from Installed Today as a supply-only heat pump water heater or as a complete supply and install package in selected Brisbane and Gold Coast service areas.

Choose the unit only if you already have a licensed plumber and electrician arranged, or check your supply and install package to confirm standard installation, valve kit requirements, outdoor location suitability, drainage, electrical connection requirements, site access and available installation timeframes before checkout.

The Rheem MPi-325 Series II is a 325L heat pump hot water system designed for small to medium electric water heater replacement. With 325L storage capacity, 180L boost capacity, 3.6kW backup element, R134a refrigerant, two-piece system configuration, and suitability for up to 5 people under Rheem’s stated assumptions, it is a practical heat pump upgrade option for households wanting to reduce water heating energy use compared with standard electric storage.

About the Rheem MPi-325 Series II Heat Pump

The Rheem MPi-325 Series II Heat Pump uses environmental heat pump technology to absorb heat from the surrounding air and transfer it into stored water.

Instead of relying only on direct electric element heating, the system uses a refrigeration cycle to heat water more efficiently. Rheem positions the MPi-325 as using around one third of the energy of a standard electric water heater under suitable conditions, with potential water heating energy savings of up to 65% in Zone 3 when replacing an electric water heater of similar size.

The MPi-325 is recommended for replacement of small to medium electric water heaters across climate Zones 1 to 4. It is also designed to work day and night because it does not rely on roof-mounted solar collectors or direct sunlight.

Buy Rheem MPi-325 Supply Only

Order the Rheem MPi-325 Series II Heat Pump Hot Water System online as a supply-only product. This option is ideal if you already have a licensed plumber, electrician or installer arranged and only need the unit supplied.

The supply-only product price is for the hot water system itself. Installation, old system removal, disposal, valve kits, electrical work, plumbing alterations, drainage changes, compliance upgrades and additional site requirements are not included unless selected separately as add-ons.

Supply-only is best for customers searching for:

• Rheem MPi-325 price

• Rheem MPi-325 Series II heat pump for sale

• Rheem 551325 heat pump hot water system

• Rheem MPi 325L heat pump supply only

• 325L heat pump hot water system supply only

• Rheem heat pump water heater

• Rheem MPi heat pump replacement

• R134a heat pump hot water system

Rheem MPi-325 Supplied and Installed in Brisbane & Gold Coast

Installed Today can supply and install the Rheem MPi-325 Series II Heat Pump Hot Water System in selected Brisbane and Gold Coast service areas.

This option is designed for customers who want the heat pump supplied and professionally installed through one streamlined online order. The supply and install pathway helps confirm whether this system suits your property, whether a valve kit is required, whether the installation location is suitable, whether drainage is available, whether the electrical connection is suitable, and whether any additional installation add-ons may be needed before checkout.

The installed-from price is based on the product plus the matching standard installation option. Final pricing may vary depending on site access, electrical suitability, drainage, valve requirements, old system removal or disposal selections, pipework changes, base requirements, compliance requirements and selected add-ons.

Rheem MPi-325 Installation in Brisbane

For Brisbane customers, the Rheem MPi-325 Series II Heat Pump can be ordered with supply and install options through Installed Today. This is suitable for homes replacing an existing electric hot water system where the current location, access, plumbing, drainage and electrical setup are suitable for the selected installation option.

The 325L storage capacity can suit Brisbane homes, townhouses, rental properties and small to medium family households wanting a heat pump upgrade from standard electric storage.

Customers in selected Brisbane suburbs can complete the installation check before checkout to confirm whether standard heat pump installation, valve kit selection, drainage, electrical work, pipework, old system removal or disposal options may be required.

This makes the page suitable for customers searching for Rheem MPi-325 installation Brisbane, Rheem heat pump supplied and installed Brisbane, and 325L heat pump hot water replacement Brisbane.

Rheem MPi-325 Installation in Gold Coast

Gold Coast customers can also order the Rheem MPi-325 Series II Heat Pump Hot Water System with supply and install options in selected service areas.

This pathway is useful for homeowners, landlords, property managers and renovators who want the product and installation organised together instead of buying the heat pump separately and arranging trades afterwards.

Complete the supply and install check to confirm whether the existing setup is suitable and whether additional items such as valve kits, drainage, electrical connection requirements, pipework, base support, access requirements or old system disposal may be required.

This helps customers searching for Rheem MPi-325 installed Gold Coast, Rheem heat pump installation Gold Coast, and 325L heat pump supply and install Gold Coast.

Is the Rheem MPi-325 Right for Your Home?

The Rheem MPi-325 Series II Heat Pump may be suitable if you are replacing a small to medium electric storage hot water system and want a heat pump option from one of Australia’s most recognised hot water brands.

It is commonly suited to homes where a standard electric water heater is being replaced, especially where the property has suitable outdoor space, airflow, drainage and electrical supply for a heat pump installation.

Rheem lists the MPi-325 as suitable for up to 5 people under its stated usage assumptions. Real-world suitability depends on shower length, hot water usage, tariff setup, climate, installation location, airflow, drainage, electrical supply and household hot water habits.

This system may suit you if:

• You are replacing an existing electric hot water system

• You want a 325L heat pump hot water system

• Your household has up to 5 people under Rheem’s stated assumptions

• You want a heat pump designed for small to medium electric water heater replacement

• You want a system that does not rely on direct sunlight

• You want a 3.6kW boost element for backup support

• You want a two-piece heat pump system configuration

• Your property has suitable airflow, drainage and installation space

• Your electrical setup can support the required circuit

• You want the choice of supply only or supply and install

Extra work may be required if:

• The system is being moved to a new location

• The existing electrical connection does not suit the heat pump

• A licensed electrician is required to alter or upgrade the circuit

• Existing valves are old, missing or non-compliant

• Extra pipework or drainage changes are needed

• Access is restricted

• A compliant base, tray, drainage or insulation is required

• The old system needs additional removal or disposal work

• The installation location has poor airflow or unsuitable clearances

• The existing setup does not suit a heat pump installation

Key Features of the Rheem MPi-325 Series II

• 325L heat pump hot water system

• Model 551325

• Suitable for up to 5 people under Rheem’s stated usage assumptions

• Recommended for small to medium electric water heater replacement

• Suitable for climate Zones 1 to 4

• Uses heat from surrounding air to heat water

• Does not rely on direct sunlight or roof-mounted solar panels

• Multi-pass heating technology

• Constant recovery design to help minimise energy use

• Two-piece system configuration

• Designed for one plumber installation where site conditions allow

• COP of 3.6 at 19°C under stated test conditions

• Can save up to 65% on water heating energy consumption in Zone 3 compared with an electric water heater under Rheem’s stated conditions

• 3.6kW boost element

• Frost protection support

• LED display for operating status

• R134a refrigerant

• 800W rated heat pump power input

• 15A recommended electrical circuit

• 52 dB(A) listed noise level at 1 metre under test conditions

• Eligible for STCs where requirements are met

• May be eligible for additional incentives in some states

• Manufactured in Australia

• 5-year cylinder supply warranty under Rheem warranty terms

• 3-year cylinder labour warranty under Rheem warranty terms

• 2-year sealed system supply and labour warranty under Rheem warranty terms

• 1-year parts supply and labour warranty under Rheem warranty terms

Quick Specs

Brand: Rheem
Range: Rheem MPi Series II Heat Pump
Product: Rheem MPi-325 Series II Heat Pump
Model: 551325
System Type: Heat Pump Hot Water System
Storage Capacity: 325L
Boost Capacity: 180L
Recommended Household Size: Up to 5 people under Rheem’s stated usage assumptions
Rated Heat Pump Power Input: 800W
Element Rating: 3.6kW
Recommended Electrical Circuit: 15A
Refrigerant: R134a
COP: 3.6 at 19°C under stated test conditions
Noise Level: 52 dB(A) at 1 metre under test conditions
Tank Height: 1631mm
Tank Width: 863mm
Tank Depth: 638mm
Heat Pump Module Weight: 42kg
Tank Weight Empty: 88kg
Water Connections: Rp 3/4
TPR Valve Setting: 1000 kPa
Expansion Control Valve Setting: 850 kPa
Max Mains Supply Pressure With ECV: 680 kPa
Max Mains Supply Pressure Without ECV: 800 kPa
Government Incentive Eligibility: STCs where requirements are met
Cylinder Warranty: 5 years, subject to Rheem warranty terms
Cylinder Labour Warranty: 3 years, subject to Rheem warranty terms
Sealed System Warranty: 2 years supply and labour, subject to Rheem warranty terms
Parts Warranty: 1 year supply and labour, subject to Rheem warranty terms

Heat Pump Performance

The Rheem MPi-325 Series II is designed to adjust performance depending on ambient air temperature, humidity and incoming water temperature.

Under Rheem’s listed test conditions, performance is shown as:

At 7°C ambient air temperature and 86% relative humidity:
Average heating capacity of 1.5kW, recovery rate of 28 L/hr at a 45°C rise, and average COP of 2.8

At 19°C ambient air temperature and 65% relative humidity:
Average heating capacity of 1.9kW, recovery rate of 36 L/hr at a 45°C rise, and average COP of 3.6

At 33°C ambient air temperature and 35% relative humidity:
Average heating capacity of 2.5kW, recovery rate of 47 L/hr at a 45°C rise, and average COP of 4.2

At 33°C ambient air temperature and 59% relative humidity:
Average heating capacity of 2.6kW, recovery rate of 50 L/hr at a 45°C rise, and average COP of 4.5

Actual performance can vary depending on local climate, time of day, water temperature, installation location, airflow, household use and tariff setup.

Multi-Pass Heating Technology

The Rheem MPi-325 Series II uses multi-pass heating, where water passes through the heat exchanger multiple times during the heating process.

This design helps heat water isothermally and supports steady, efficient hot water production. It is designed to work with the system’s constant recovery approach, helping optimise heating while reducing energy use compared with standard electric storage.

3.6kW Boost Element

The Rheem MPi-325 includes a 3.6kW boost element.

The boost element provides frost protection and backup heating support during very cold conditions. It is designed to help ensure hot water remains available when heat pump operation needs support.

This can be useful for households that want heat pump efficiency most of the time, with electric backup available when required.

Two-Piece System Configuration

The Rheem MPi-325 Series II uses a two-piece configuration with a separate tank and heat pump module.

This setup can help with installation flexibility and allows single plumber installation where the site conditions are suitable. The installation location still needs proper clearances, airflow, drainage, access and electrical connection.

The two-piece design also means the site needs to be checked carefully before ordering, especially where access, side clearance, wall clearance or installation area is limited.

Energy Savings Potential

The Rheem MPi-325 Series II is designed to reduce water heating energy use compared with a standard electric water heater.

Rheem lists potential savings of up to 65% in Zone 3 when replacing an electric water heater of similar size under stated modelling conditions.

Actual savings can vary depending on household usage, system size being replaced, electricity tariff, location, climate, hot water demand and installation setup.

Electrical Connection and Tariff Suitability

The Rheem MPi-325 is listed with a 15A recommended electrical circuit and a 3.6kW element rating.

Rheem notes the system is recommended for connection to either a 24-hour continuous tariff or an extended off-peak tariff of at least 16 hours per day, depending on site and replacement conditions.

If replacing an electric water heater greater than 160L, a 24-hour continuous tariff is generally recommended for this heat pump. Customers should confirm electrical and tariff suitability before ordering or installation.

STCs and Incentives

The Rheem MPi-325 Series II may be eligible for Small-scale Technology Certificates where requirements are met.

Eligibility and value can vary depending on installation location, climate zone, product model, installation date, installer requirements and program rules. Some states may also offer additional incentives where conditions are met.

Any rebate, STC discount or incentive should be confirmed before ordering or installation.

Common Uses

The Rheem MPi-325 Series II Heat Pump can be suitable for:

• Electric hot water system replacement

• Small to medium electric water heater replacement

• Heat pump hot water upgrades

• Family homes

• Townhouses

• Rental properties

• Investment properties

• Homes with up to 5 people under Rheem’s stated assumptions

• Homes wanting lower energy use than standard electric storage

• Homes where roof-mounted solar hot water may not be suitable

• Properties needing a 325L heat pump hot water system

• Supply-only orders where a licensed installer is already arranged

• Supply and install orders in selected Brisbane and Gold Coast areas

Suitability depends on household size, hot water usage, tariff setup, installation location, airflow, drainage, plumbing condition, electrical supply and compliance requirements.

Why Order From Installed Today?

Installed Today gives customers a simple way to order the Rheem MPi-325 Series II Heat Pump Hot Water System as either a product-only purchase or a supply and install package in selected Brisbane and Gold Coast service areas.

You can compare the unit-only price, check the installed-from price, complete the installation compatibility check and select matching installation add-ons before checkout.

Why customers choose Installed Today:

• Supply only or supply and install options

• Installed-from pricing shown separately

• Compatibility check before checkout

• Valve kits and installation add-ons available online

• Brisbane and Gold Coast service area support

• Suitable for heat pump hot water replacement orders

• Clear product and installation pathway before checkout

• Practical 325L heat pump replacement option

• Product-only ordering for customers with their own licensed installer

• Supply and install pathway for selected heat pump upgrades

• Rheem heat pump hot water system from a recognised Australian hot water brand

Frequently Asked Questions

Can I buy the Rheem MPi-325 supply only?

Yes. You can buy the Rheem MPi-325 Series II as a supply-only product if you already have a licensed installer arranged. The unit-only price does not include installation, old system removal, disposal, valve kits, electrical work, plumbing alterations, drainage changes or compliance upgrades unless selected separately.

Can I get the Rheem MPi-325 installed in Brisbane?

Yes. Supply and install options are available in selected Brisbane service areas. Complete the installation check to confirm whether the standard heat pump installation option suits your property and whether additional add-ons may be required.

Can I get the Rheem MPi-325 installed in Gold Coast?

Yes. Selected Gold Coast service areas are available. Installation suitability depends on access, existing plumbing, electrical requirements, drainage, valve condition, airflow, clearances, compliance and selected add-ons.

Is installation included in the product price?

No. The main product price is the unit-only price. The installed-from price is shown separately so you can compare supply only against supply and install.

What does the installed-from price include?

The installed-from price is based on the Rheem MPi-325 unit plus the matching standard installation option. Final pricing may vary depending on valve kits, removal or disposal selections, pipework, drainage, electrical work, access, compliance and other selected add-ons.

Do I need a valve kit?

Many hot water replacements require compatible valves to meet installation and compliance requirements. The installation check helps identify whether a valve kit is recommended for your order.

What is the model number for the Rheem MPi-325?

The Rheem MPi-325 Series II model number is 551325.

What is the storage capacity?

The Rheem MPi-325 has a 325L storage capacity.

What is the boost capacity?

The Rheem MPi-325 has a listed 180L boost capacity.

How many people is the Rheem MPi-325 suitable for?

Rheem lists the MPi-325 as suitable for up to 5 people under stated usage assumptions. Actual suitability depends on shower length, hot water usage, tariff setup, climate and household habits.

What refrigerant does the Rheem MPi-325 use?

The Rheem MPi-325 uses R134a refrigerant.

What is the COP of the Rheem MPi-325?

The Rheem MPi-325 has a listed average COP of 3.6 at 19°C under stated test conditions.

What is the recovery rate?

At 19°C ambient air temperature and 65% relative humidity, the Rheem MPi-325 is listed with a recovery rate of 36 L/hr at a 45°C rise under stated test conditions.

What size backup element does the Rheem MPi-325 have?

The Rheem MPi-325 has a listed 3.6kW boost element.

What electrical circuit does the Rheem MPi-325 need?

The Rheem MPi-325 is listed with a 15A recommended electrical circuit. Electrical suitability should be confirmed before installation.

Does the Rheem MPi-325 need direct sunlight?

No. The Rheem MPi-325 uses heat from the surrounding air and does not rely on direct sunlight or roof-mounted solar panels.

Is the Rheem MPi-325 suitable for replacing an electric hot water system?

Yes. The Rheem MPi-325 is recommended for replacement of small to medium electric water heaters in climate Zones 1 to 4 where the property and household demand suit the system.

Can the Rheem MPi-325 reduce running costs?

Yes. Rheem lists potential water heating energy savings of up to 65% in Zone 3 compared with an electric water heater of similar size under stated modelling conditions. Actual savings depend on location, household usage, tariff setup, installation conditions and the system being replaced.

Is the Rheem MPi-325 eligible for STCs?

The Rheem MPi-325 may be eligible for STCs where requirements are met. Eligibility and value can vary depending on location, installation year, product model, installer requirements and program rules.

What is the noise level of the Rheem MPi-325?

The Rheem MPi-325 is listed with a noise level of 52 dB(A) at 1 metre under test conditions. Installed noise can vary depending on walls, nearby structures, clearances and site layout.

What is the warranty on the Rheem MPi-325?

Rheem lists the MPi-325 with a 5-year cylinder supply warranty, 3-year cylinder labour warranty, 2-year sealed system supply and labour warranty, and 1-year supply and labour warranty on all other parts, subject to Rheem warranty terms and conditions.

What is the difference between the Rheem MPi-325 and AmbiPower 280e?

The Rheem MPi-325 is a 325L Series II heat pump with a two-piece configuration, R134a refrigerant, 3.6kW boost element and up to 5-person suitability. The AmbiPower 280e is a newer 280L heat pump using R290 natural refrigerant, with plug-in or hardwired model options depending on the selected variant.

Brand -

Model -

Volume (L) -

Height (mm) -

Width (mm) -

Weight (kg) -

Energy Rating - 

Made In -

Made By -

Maximum Warranty -

Internal Material -

Noise Level (dBa) -

Recommend Occupants -

Recommended Bathrooms -

Hassle-Free Installation – Done Right by Trusted Experts!

Need professional installation? We’ve got you covered! Our optional installation service connects you with our network of certified, trusted contractors, ensuring a smooth and stress-free setup.

How It Works:

🔹 Step 1: Select Installation Service
Choose to include professional installation when purchasing your new system.

🔹 Step 2: Pay for Installation Upfront
Simply add the installation service prior to adding your product to cart —no hidden fees, no surprises.

🔹 Step 3: We Assign a Certified Contractor
We’ll match you with a licensed, experienced contractor from our network to handle the installation.

🔹 Step 4: Schedule Your Installation
The assigned contractor will contact you directly to arrange a convenient time for installation.

🔹 Step 5: Direct Support When You Need It
For any installation-related questions, your contractor is your first point of contact. If any issues arise, our team is here to help.

🚨 Please Note: Installed Today supplies the product and connects you with a certified contractor for installation.

We’re committed to delivering top-quality products and facilitating a seamless installation experience. Have product questions? Reach out to us anytime! 🔥

Experience the "Installed Today" Difference with Our Verified Installers

When you choose "Installed Today" for your installation needs, you're not just getting a product; you're gaining access to a network of rigorously verified installers dedicated to providing you with an exceptional service experience. Here's what you can expect when you opt for an installation by an "Installed Today" verified installer:

Professional and Efficient Service

• Prompt Communication: Our verified installers will contact you within 2 business hours of receiving your order details to confirm and begin scheduling your installation at the earliest convenience.
• Expert Installation: All "Installed Today" installers are highly skilled and qualified, ensuring your product is installed according to the highest industry standards and specific regulations in your area.
• Clear and Professional Communication: From the moment they receive your order until the completion of your installation, our installers maintain clear and professional communication, providing you with all necessary information regarding your installation.

Peace of Mind

• Insurance and Liability: Every "Installed Today" verified installer maintains comprehensive insurance coverage, giving you peace of mind knowing you're protected throughout the installation process.
• Warranty and Quality Assurance: Enjoy a warranty on your installation, guaranteeing rectification work at no additional charge in the unlikely event of any deficiencies. Our installers strive to achieve a minimum 4.5-star average rating across major review platforms, reflecting our commitment to excellence and customer satisfaction.

Customer-Centric Policies

• Customer Dispute Resolution: In the rare event of a dispute, our installers are committed to acknowledging and initiating the resolution process within 1 business day, aiming for a swift and satisfactory resolution within 5 business days.
• Rectification Work Timeframes: Should any rectification work be necessary, it will be acknowledged within 1 business day and completed within 2 business days, ensuring minimal inconvenience to you.

Additional Services at Transparent Rates

• Beyond Basic Installation: Our verified installers offer a range of additional services to complement your installation. All available services and their set rates are communicated upfront, ensuring no surprises.

By choosing "Installed Today," you're not just installing a product; you're investing in a seamless, quality service that values your time and peace of mind. Trust in our verified installers to exceed your expectations with their professionalism, expertise, and commitment to excellence.

This product description outlines the benefits and assurances provided by "Installed Today" verified installers, designed to inform and reassure customers about the high level of service they can expect.

DELIVERY TIMES WITH INSTALLATION - HOT WATER SYSTEMS EXC. HEAT PUMPS

Greater Brisbane and Gold Coast (EXCLUDING BAY ISLANDS) - up to 2 business days

Toowoomba, Tweed Heads and Sunshine Coast - up to 3 business days

DELIVERY TIMES WITHOUT INSTALLATION - HOT WATER SYSTEMS EXC. HEAT PUMPS

Greater Brisbane and Gold Coast (EXCLUDING BAY ISLANDS) - up to 3 business days

Toowoomba, Tweed Heads and Sunshine Coast - up to 5 business days

Harvey Bay, Cairns and Townsville - up to 5 business days

Metropolitan Cities - up to 5 Business Days

Listed Metropolitan Centers - up to 10 Business Days

DELIVERY TIMES WITH INSTALLATION - HEAT PUMPS

Greater Brisbane and Gold Coast (EXCLUDING BAY ISLANDS) - up to 2 business days

Toowoomba, Tweed Heads and Sunshine Coast - up to 5 business days

DELIVERY TIMES WITHOUT INSTALLATION - HEAT PUMPS

Greater Brisbane and Gold Coast (EXCLUDING BAY ISLANDS) - up to 5 business days

Toowoomba, Tweed Heads and Sunshine Coast - up to 5 business days

Metropolitan Cities - up to 5 Business Days

Listed Metropolitan Centers - up to 10 Business Days

DELIVERY TIMES WITH/WITHOUT INSTALLATION - PUMPS AND WATER FILTERS

Greater Brisbane and Gold Coast - up to 5 business days

Toowoomba, Tweed Heads and Sunshine Coast - up to 5 business days

Harvey Bay, Cairns and Townsville - up to 10 business days

**PLEASE NOTE ORDERS OUTSIDE OF THESE AREAS WILL BE REFUNDED AS SOON AS POSSIBLE**

SERVICED METROPOLITIAN CENTRES & CITIES

-Brisbane (EXCLUDING BAY ISLANDS)

-Gold Coast

-Sunshine Coast

-Toowoomba

-Coffs Harbour

-Tamworth

-Canberra

-Sydney (EXCLUDING ISLANDS)

-Bathurst

-Melbourne

-Ballarat

-Geelong

-Adelaide

-Perth

-Darwin

-Cairns

-Townsville

-Harvey Bay

-Rockhampton

-Bundaberg

-Tweed Heads

-Wollongong