The Joule Invacyl Slimline Direct Unvented Cylinder (90L) is a compact, high-quality stainless steel hot water cylinder designed for unvented mains-pressure systems. Its slimline profile provides reliable mains-pressure hot water for showers, taps and appliances while helping save valuable space in cupboards, plant rooms and other installation areas. With efficient thermal insulation and durable stainless steel construction, it is well suited to small homes, flats, apartments and retrofit projects where space and dependable hot-water performance are important.
Key Features
90-Litre Compact Capacity
The 90-litre capacity is suited to smaller households, flats and apartments with modest hot-water requirements.
Slimline Space-Saving Design
The slimline format helps maximise hot-water storage while reducing the footprint required in cupboards, plant rooms and other installation spaces.
LDX 2101 Stainless Steel
The cylinder is manufactured from LDX 2101 stainless steel for durable construction, corrosion resistance and long service life.
50mm PU Foam Insulation
Dense 50mm PU foam insulation helps improve heat retention, with a specified heat loss of 1.15 kWh over 24 hours.
3kW Immersion Heater
A single 3kW immersion heater operating at 230V provides effective electric heating for hot-water reheating.
Mains-Pressure Performance
Designed for a maximum mains water pressure of 10 bar and an operating pressure of 7 bar, supporting reliable hot-water flow to connected outlets.
Compact Hot Water Storage
The Joule Invacyl 90L combines compact hot-water storage with a slimline design, making it suitable for installations where available space is limited. Its 90-litre capacity provides a practical solution for smaller properties while maintaining mains-pressure hot-water delivery.
Small Properties
Suitable for small residential homes, flats and apartments with modest hot-water requirements.
Space-Conscious Installations
The slimline design is well suited to cupboards, plant rooms and retrofit installations where space is restricted.
Mains-Pressure Hot Water
Designed to provide mains-pressure hot water for showers, taps and appliances.
Efficient Heat Retention
Dense 50mm PU foam insulation helps retain stored heat and delivers a stated heat loss of 1.15 kWh/24h.
Safety & Performance
The Joule Invacyl 90L is designed for unvented hot-water applications with a maximum mains water pressure of 10 bar and an operating pressure of 7 bar. The specified safety temperature is 90°C, and the cylinder is tested to BS EN 50440:2015.
Its dense 50mm PU foam insulation provides effective thermal retention, with a stated heat loss of 1.15 kWh/24h. The cylinder is fitted with one 3kW immersion heater operating at 230V.
Technical Specifications
| Product Model |
Joule Invacyl Slimline Direct Unvented Cylinder (90L) |
| Actual Capacity |
90 L |
| Unit Weight Empty |
22 kg |
| Unit Weight Full |
106 kg |
| Cylinder Material |
LDX 2101 Stainless Steel |
| Outer Casing |
Coated Mild Steel |
| Thermal Insulation |
Dense PU Foam |
| Foam Thickness |
50 mm |
| Number of Immersions |
1 |
| Immersion Specification |
3 kW @ 230 V |
| Maximum Mains Water Pressure |
10 bar |
| Operating Pressure (T & P) |
7 bar |
| Safety Temperature |
90°C |
| Heat Loss |
1.15 kWh/24h |
| Tested To Standard |
BS EN 50440:2015 |
| Warranty Terms |
25 Years |
Ideal For
- Small residential homes, flats and apartments
- Renovation and retrofit projects where installation space is limited
- Bathrooms and kitchens requiring mains-pressure hot water for one or two outlets
- Small offices or commercial spaces with modest hot-water demand
- Installations requiring a compact, low-maintenance and energy-efficient hot-water cylinder
Frequently Asked Questions
What is the capacity of the Joule Invacyl 90L?
The cylinder has an actual hot-water capacity of 90 litres.
Is the Joule Invacyl 90L a direct unvented cylinder?
Yes. The Joule Invacyl 90L is a direct unvented hot-water cylinder fitted with one 3kW immersion heater.
What material is the cylinder made from?
The cylinder is manufactured from LDX 2101 stainless steel and has a coated mild steel outer casing.
How many immersion heaters does it have?
The Joule Invacyl 90L has one immersion heater specified at 3kW @ 230V.
What is the warranty?
The Joule Invacyl Slimline Direct Unvented Cylinder 90L has a stated 25-year warranty.
Compact Mains-Pressure Hot Water Storage
With 90 litres of storage, a 3kW immersion heater, 50mm PU foam insulation and durable LDX 2101 stainless steel construction, the Joule Invacyl Slimline Direct Unvented Cylinder is designed for smaller properties and space-conscious installations requiring reliable mains-pressure hot water.
At GetPlumb, we strive to provide reliable and cost-effective delivery options to our customers. Please review our shipping policy below.
🆓 Free Local Delivery (Orders £100 & above)
We offer FREE delivery on orders £100 or more
for selected local areas.
Eligible Postcodes Include:
- RG*
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- W1* – W9*
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Delivery Time: 2–4 working days
Shipping Cost: £0.00
📦 Standard Shipping (Weight-Based Rates)
For orders that do not qualify for free delivery, standard
shipping rates apply based on total cart weight.
- For cart weight between 0–2 kg, the shipping cost is £4.50 with a delivery time of 2–4 working days.
- For cart weight between 2–24 kg, the shipping cost is £9.99 with a delivery time of 2–4 working days.
- For cart weight between 24 kg and above, the shipping cost is £60 with a delivery time of 2–4 working days.
🧱 Block Salt (Harvey’s) – Unit-Based Shipping
This rate applies only to Harvey’s block salt products.
- £7.99 is charged for every 3 items.
- The charge increases by £7.99 for each additional set of 3 items.
Examples:
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- 4–6 items → £15.98
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Delivery Time: 2–4 working days
📏 Large / Long Items (Length-Based Shipping)
For oversized items where the product length is 1.5 metres or more:
Conditions:
- Product length ≥ 1.5 m
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Shipping Cost: £18.00 (flat rate)
Delivery Time: 2–4 working days
Collection from Store
Customers can also choose to collect their order from our store in
Reading, UK, at no additional charge. For any questions regarding shipping, please contact our support team at online@getplumb.co.uk.
