If you’re looking for a Purity instant water heater for your home, you may be deciding between 7, 9, 11, and 13kW models. Will the difference affect your shower experience, and is the higher-powered model worth the extra cost?

Choosing a Purity instant water heater depends on your hot-water needs and your home’s electrical readiness. Smart features such as Wi-Fi and remote control make operation easier, but the priority is whether the heater can heat the amount of water you need, particularly in winter.

In this Alreyada Store guide, we explain the features and limitations of Purity instant water heaters, the differences between power ratings, model prices, and the installation requirements to check before buying.

What Is a Purity Instant Water Heater, and How Does It Work?

A Purity instant water heater is an electric appliance that heats water as it passes through the unit, without a hot-water storage tank. When you open the tap and the operating conditions are met, heating begins according to the appliance’s settings and capacity.

This means you do not need to wait for a full tank to heat up before use. However, the time it takes hot water to reach your tap still depends on pipe length and the cold water already inside the pipes.

Having no tank does not mean the heater can heat any volume of water to the same temperature. Performance depends on three main factors:

• The appliance’s electrical power.
• Incoming water temperature.
• The required water flow rate.

Choosing the right power rating is therefore more important than simply choosing a heater described as “instant.”

What Are the Features of a Purity Instant Water Heater?

Heating During Use Without a Storage Tank

The appliance heats flowing water, so it does not depend on a stored volume of hot water that can run out and require reheating. However, the available hot-water flow remains limited by the heater’s output and operating conditions.

A Design That Saves Tank Space

Without a large storage tank, you have more flexibility when choosing an installation location, provided you follow the installation instructions and leave suitable access for maintenance and connections.

Different Power Ratings for Different Needs

The 7, 9, 11, and 13kW options allow you to match the heater’s output to your usage and home setup, rather than buying a model with too much or too little power for your needs.

Digital Display and Smart Controls

The P101 model pages discussed in this article list a digital display, Wi-Fi control, and a remote control. These features make monitoring and adjusting settings easier, but they do not increase heating output.

No Gas Connection or Combustion Flue Required

The heater runs on electricity, so it does not need a gas supply or a combustion flue. This makes it worth considering for homes without gas, after confirming that the electrical installation is suitable.

What Are Its Drawbacks and Limitations Before Buying?

It Requires a Suitable Electrical Installation

High-powered instant water heaters require an assessment of electrical capacity, wiring, and protective devices. A nearby power source does not mean the location is ready. Preparation work may need to be included in your purchase budget.

Flow and Temperature Are Connected

At a fixed heating output, increasing the amount of flowing water reduces the temperature rise the heater can provide. A high-flow shower or an additional open outlet may therefore change your experience.

Winter Performance Needs Separate Assessment

Colder water requires more energy to reach the same outlet temperature. A model that meets your needs in summer may require a lower flow in winter to achieve your preferred temperature.

It Does Not Fix Low Water Pressure

The heater is not a pump for increasing supply pressure. If the water supply is weak, confirm that its pressure and flow meet the model’s operating requirements.

Heating Stops During a Power Cut

Because the appliance relies on electricity and has no stored hot water, a power interruption stops heating during use.

These are limitations of instant water heating that should be understood before buying, rather than evidence of an appliance fault.

Differences Between Purity 7, 9, 11, and 13kW Models

The main difference between power ratings is the energy available for heating water. Under the same operating conditions and at the same inlet and outlet temperatures, a higher-powered heater can heat a greater flow of water.

However, choosing a power rating is not as simple as assigning each number to a fixed number of bathrooms. Shower fittings, usage habits, and winter temperatures affect the result.

This table provides a starting point for comparison. It does not guarantee suitability for a particular use without checking model data and conditions at your home.

Also compare power ratings at the same operating voltage. Some product pages list different outputs at different voltages, so do not choose based only on the highest figure shown.

Which Model Should You Choose for the Bathroom or Kitchen?

If Your Main Use Is the Kitchen Sink

Start by identifying how much hot water you need and whether another outlet will operate simultaneously. A 7kW model is worth assessing for limited use, but suitability depends on flow and the required water temperature.

Installing the heater near the outlet may reduce the wait for hot water, provided the location complies with the manufacturer’s instructions.

If Your Main Use Is Showering

Identify your shower type and flow rate before assessing the appropriate power rating. A high-flow shower requires more water to be heated than a lower-flow shower, even if both serve a single bathroom.

Do not choose 9 or 11kW simply because a general description says it is suitable for a bathroom. Check the required winter performance and your electrical setup.

If You Want to Use Multiple Outlets

The 11 and 13kW models are worth comparing for higher demand, but you need to assess combined flow and the appliance’s ability to heat it to a suitable temperature.

The number of outlets connected to a heater is different from the number that can run simultaneously at the required performance.

Is a Purity Instant Water Heater Suitable for Winter Showers?

It can be, provided you choose a power rating that matches your shower flow, incoming water temperature, and electrical installation.

For example, heating water from 15°C to 40°C requires a 25°C temperature rise. If water enters at 10°C, the heater needs to provide a 30°C rise to reach the same outlet temperature.

These figures illustrate the principle; they are not test results for a specific model. At a fixed heating output, a greater required temperature rise reduces the flow that can be heated to the same outlet temperature.

Before buying, explain the following to the selection team:

• How cold your incoming water becomes in winter.
• Your shower type and preferred flow.
• Whether another basin or shower will run simultaneously.
• The distance between the heater and the outlets.

This helps you choose based on the experience you need, rather than relying solely on the power rating or brand name.

What Should You Check Before Installation?

Have the Electrical Installation Assessed by a Qualified Professional

Ask for an assessment of available electrical capacity, the distribution board, cables, earthing, and protective devices according to the model’s instructions.

Cable sizing and circuit-breaker selection depend on power, cable-run length, and installation method. Do not rely on an existing connection without inspection.

Prepare the Plumbing and Check Water Flow

Make sure water connections and mixers are complete and that water pressure and flow meet operating requirements. Address any supply problem before installing the heater.

Follow Installation Position and Location Requirements

The product pages specify vertical installation, separation from direct water sources, and maintenance access. Review the model’s instructions before choosing its location, particularly if you plan to install it under a sink or within an enclosed space.

Arrange Authorized Installation

The published installation instructions require an authorized company technician to maintain warranty validity. Coordinate preparation work with the company before carrying it out, and confirm the required work and its cost.

Purity Instant Water Heater Prices at Alreyada Store

The following examples show P101 models and their reference prices, with direct links to their English product pages:

Prices reflect the product pages when the article was prepared on 26 October 2026 and may change depending on offers and availability.

Budget for the appliance, preparation work, installation, and any required accessories. Ask about each item before confirming your order.

You can also browse instant water heaters at Alreyada Store to review the available options.

Purity Water Heater Warranty and After-Sales Service

The model pages discussed list an authorized five-year warranty from Purity. Review the warranty document to confirm when coverage begins, what it includes, and the installation and usage conditions.

Keep your invoice, model details, and serial number. Ask about warranty activation and maintenance bookings. The product instructions list 16495 as the Purity contact number for registering an installation request.

If you notice unusual temperature changes or an error code, consult the model’s manual and authorized service team rather than attempting changes to connections or protective devices.

Why Buy a Purity Instant Water Heater from Alreyada Store?

Alreyada Store lets you compare power ratings, colors, and prices and review model specifications before buying. You can also ask for help choosing a heater and checking preparation requirements and installment options.

Rather than starting with color or price alone, explain your needs: kitchen or shower, one outlet or simultaneous use, and the available electrical setup. These details make the comparison more relevant to your actual usage.

Installment Options for Purity Water Heaters

Review Alreyada Store’s installment steps and conditions and the plans available for the product when you order.

If a Triple Zero offer is displayed, confirm its duration, participating provider, and whether installments are calculated using the price before or after the discount. Review the total amount payable alongside the monthly payment before choosing.

Frequently Asked Questions About Purity Instant Water Heaters

Does a Purity Instant Water Heater Have a Tank?

No. The instant models discussed heat water as it passes through the appliance, without a hot-water storage tank.

Can It Run a Shower and Basin at the Same Time?

That depends on the model’s output, combined flow, and incoming water temperature. Connecting both outlets does not guarantee that they can operate together at your required temperature and flow under every condition.

Does a Purity Water Heater Work with Low Water Pressure?

Water pressure and flow must meet the model’s minimum requirements. Have a technician check the measurements; the heater itself does not increase supply pressure.

Do All Purity Models Have Wi-Fi and a Remote Control?

The P101 models linked in this article list Wi-Fi and remote control among their specifications. Do not assume the same applies to every version. Check the model number and package contents before buying.

Does a Different Heater Color Mean Different Performance?

Color alone does not determine performance. If power, version, and specifications match, the difference may be cosmetic. Compare model numbers and specifications rather than relying on appearance.

Does the Heater Price Include Installation and Delivery?

Do not assume it includes both. Check delivery terms for your address and ask separately about installation, preparation work, and accessories before confirming your order.

Choosing the right Purity instant water heater starts with your hot-water needs and electrical readiness. Compare the linked models, identify your usage and budget, and contact Alreyada Store on 01273000070 for help choosing, checking availability, and reviewing installment options.