Small flat or one outlet
You need about 30 litres for a sink or a short draw, and a competent person will confirm the electrics and the relief arrangement. This is the smallest and least expensive store in the set.
Hot water cylinder comparison 2026
The best hot water cylinders, compared.
Top pick: TESY BiLight 30 litre – Clear 30 litre capacity, a readable 1,500 W element and the lowest price in this set, at about £139.99. The shared 4.4 from 72 ratings is not treated as a separate test of this size. Best value: TESY BiLight 50 litre horizontal – Horizontal 50 litres at about £159.99, with a readable 1,500 W element and a stated heat-up. It needs a 16 A fused spur, and the captured listing has no star line. Updated 17.10.2026.
A hot water cylinder stores heated water for taps and showers. None of them describes a coil for a boiler or a heat pump. You are choosing litres, a wattage the listing actually prints in a usable way, and whether the safety parts are in the box. The 80 litre and 120 litre watt figures are not usable. The 100 litre listing is cylinder only and tells you to add a 3 bar relief valve. Read the [sizing guide](/hub/hot-water/hot-water-cylinder/sub/hot-water-cylinder-how-to-size) before you treat 50 litres as enough for a household. It is vented, fed from a cistern, or unvented, held at mains pressure with relief valves and a visible discharge. It is direct, with an immersion heater, or indirect, with a coil from a boiler or a heat pump. The 50 litre and 100 litre listings are the horizontal models. A UK review says the case is circular.
A hot water cylinder stores heated water for taps and showers. None of them describes a coil for a boiler or a heat pump.
22 products checked · 48 hrs invested · +16,400 readers
6 of 6: Best hot water cylinders compared
Swipe for more
1-2 of 6Best overall
Best value
8.8/10
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7.2/10
7.0/10
6.5/10
∼ £140
∼ £235
∼ £255
∼ £260
∼ £219
∼ £160
4.4(72)
4.4(72)
4.4(72)
3.6(7)
3.5(17)
–
Personal buying guide
Which hot water cylinder fits?
Question 1 of 2
How much stored hot water do you need?
The best hot water cylinders in detail
Our view
The TESY BiLight 30 litre gives you the smallest and least expensive store in this comparison, with a readable 1,500 W element and a stated maximum temperature of 80°C. Its compact 35 cm width makes it easier to place than the larger vertical cylinders, provided 30 litres genuinely covers the intended sink or short hot-water draw. The listing also names temperature and pressure relief protection, although the pipe connections are not included and the plug arrangement is not stated. Its 4.4-star line from 72 ratings looks useful, but the written reviews are duplicated across the 30, 80 and 120 litre TESY files, so they cannot be treated as evidence for this size alone. At about £139.99, it is our top pick within these six because its capacity, power and price are all clear, not because it can replace a family cylinder. Skip it if you need repeated showers or enough stored water for several occupants.
Pros
- Clear 30 litre capacity and 1,500 W element rating
- Lowest price in this six-product comparison
- Narrow 35 cm body for a small wall space
- Temperature and pressure relief protection stated
Cons
- Too small for typical family hot-water demand
- Pipe connections are not included
- Shared TESY review text is not specific to this size
Best for: A small flat, annexe or single point where 30 litres is enough and a competent installer confirms the safety and electrical arrangements.
Less suitable: Several occupants, repeated showers or anyone expecting a complete plug-and-fit installation kit.
Specifications
- Model
- TESY BiLight 30 litre
- Brand
- TESY
- Price
- ∼£140
- Customer rating
- 4.4/5(72)
- Type
- Direct electric
- Capacity
- 30 litres
- Orientation
- Vertical
- Power
- 1,500 W
- Max temperature
- 80°C
- Energy class
- C
- Supply
- Plug not stated
- Valve in box
- Stated, no pipes
- Empty weight
- 16 kg
- Size
- 35 × 55 cm
Common questions
Is this a hot water cylinder?
The listing titles it as a 30 litre hot water cylinder, and the item type name says TESY Bi-Light 30 litre unvented hot water cylinder.
What power does the listing state?
1,500 watts at 220 volts, with energy class C and a maximum temperature of 80°C.
What comes in the box?
The included-components line says cylinder. The special features say 15 mm water connections, and that pipe connections are not included.
Our view
The TESY BiLight 80 litre moves beyond point-of-use capacity and gives you a vertical wall-mounted store for a small household with modest demand. Its about £234.99 listing states energy class C, a 65°C maximum and a two-year warranty, but it prints the wattage as 1,500 kW, so there is no usable element rating to compare. That omission matters because recovery time is central to deciding whether 80 litres will keep pace with your routine. The listing calls the cylinder unvented and names overheat protection, yet it does not clearly confirm the valve set supplied in the box. Its 4.4-star line from 72 ratings is also shared with the 30 and 120 litre TESY files, including the same written reviews. Consider it only if an installer can verify the exact model, element rating and required safety kit before purchase.
Pros
- 80 litre capacity in a vertical wall-mounted format
- Maximum temperature of 65°C stated
- Two-year manufacturer warranty stated
Cons
- Printed 1,500 kW figure is unusable as an element rating
- Valve contents are not clearly stated
- Review text is duplicated across three TESY sizes
Best for: A small household needing more than a point-of-use store, after the installer verifies power, valves and wall loading.
Less suitable: Anyone choosing by recovery time, included safety kit or the shared 4.4-star line alone.
Specifications
- Model
- TESY BiLight 80 litre vertical
- Brand
- TESY
- Price
- ∼£235
- Customer rating
- 4.4/5(72)
- Type
- Direct, unvented
- Capacity
- 80 litres
- Orientation
- Vertical
- Max temperature
- 65°C
- Energy class
- C
- Supply
- Plug not stated
- Empty weight
- 24 kg
- Size
- 44 × 50 cm
Common questions
Does the listing call it unvented?
Yes. The title says TESY 80 litre hot water cylinder electric unvented wall mounted.
What power should you compare?
Do not use a watt figure from this listing. It prints wattage as 1,500 KW, which is not a usable domestic element rating.
What warranty is stated?
The manufacturer warranty description says 2 years. The contents line says cylinder.
Our view
The TESY BiLight 120 litre is the largest store in this comparison and may suit a home whose measured demand has outgrown the smaller wall cylinders. The listing gives a 44 cm width, 110 cm height, 30 kg empty weight and a maximum temperature of 80°C, so the wall and access route need checking before delivery. It names a thermal cut-out and a temperature and pressure safety valve, but says pipe connections are not included. The wattage is printed as 220 W beside a 220 V supply, which is too unclear to use as the element rating or to estimate recovery. Its 4.4-star line and written reviews are the same evidence shown for the 30 and 80 litre TESY listings, rather than size-specific owner feedback. At about £254.99 it is only £20 above the 80 litre model, but the unclear power specification prevents a confident recommendation without installer verification.
Pros
- Largest stated capacity in this comparison
- Thermal cut-out and safety valve named
- Two-year manufacturer warranty stated
- Only £20 more than the 80 litre listing at capture
Cons
- Printed wattage is not credible enough to compare
- Pipe connections are not included
- Shared reviews do not prove performance of the 120 litre model
Best for: A larger direct-electric wall store where an installer confirms the model, recovery input, fixings and complete safety kit.
Less suitable: A family choosing solely by litres or stars, or a property that needs an indirect boiler or heat-pump coil.
Specifications
- Model
- TESY BiLight 120 litre
- Brand
- TESY
- Price
- ∼£255
- Customer rating
- 4.4/5(72)
- Type
- Direct, unvented
- Capacity
- 120 litres
- Orientation
- Vertical
- Max temperature
- 80°C
- Energy class
- C
- Supply
- Plug not stated
- Valve in box
- Named, no pipes
- Empty weight
- 30 kg
- Size
- 44 × 110 cm
Common questions
How large is this cylinder?
The capacity field says 120 litres. Dimensions are 44 cm wide by 110 cm high, and the weight is 30 kg.
Why is power not shown?
The listing prints wattage as 220 watts and voltage as 220 volts. That watt figure is not clear enough to quote as the element rating.
Which safety parts does the listing name?
The bullets name a thermal load temperature safety cut-out and a safety temperature and pressure valve. The contents line still says cylinder, and pipe connections are not included.
Our view
The TESY BiLight 100 litre horizontal gives you substantial storage where cupboard height is limited, using a body just under one metre wide and 47 cm high. Its readable 3,000 W rating is the strongest stated element in this set, while the listing also gives 6 bar and a 60°C maximum. The trade-off is that this is explicitly a cylinder-only package: it requires a 3 bar temperature and pressure relief valve and a 1.5 mm electrical cable. The model code contains 80 even though the title says 100 litres, so the exact supplied unit should be confirmed before ordering. Its 3.6-star average covers only seven ratings, and no written review text was captured to explain the score. At about £259.99 it is the most expensive listing here, making sense only when horizontal placement is a real constraint and the extra installation parts are budgeted.
Pros
- Horizontal format for a low installation space
- Readable 3,000 W element rating
- 6 bar pressure and 60°C maximum stated
- Two-year manufacturer warranty stated
Cons
- Required 3 bar relief valve is not included
- Title capacity and model code do not agree
- Only seven ratings and no captured review text
Best for: A low, wide cupboard where 100 litres is appropriate and the installer can supply the valve, cable and fixings.
Less suitable: A simple replacement with a complete kit, or a buyer who has room for a better-documented vertical cylinder.
Specifications
- Model
- TESY BiLight 100 litre horizontal
- Brand
- TESY
- Price
- ∼£260
- Customer rating
- 3.6/5(7)
- Type
- Direct, unvented
- Capacity
- 100 litres
- Orientation
- Horizontal
- Power
- 3,000 W
- Max temperature
- 60°C
- Max pressure
- 6 bar
- Energy class
- C
- Supply
- 1.5 mm cable
- Valve in box
- No
- Empty weight
- 22 kg
- Size
- 99.5 × 47 cm
Common questions
Will it fit a low cupboard height?
The listing gives a horizontal wall-mounted style, 99.5 cm wide, 47 cm high and 46.7 cm deep, at 22 kg empty.
Is the relief valve in the box?
No. Included components say cylinder only, and that it requires a 3 bar temperature and pressure relief valve and a 1.5 mm electrical cable.
What do the title and the model code say?
The title says 100 litres. The model number is GCH 80 44 20 B12 TSR. The listing states 3,000 W, energy class C, 6 bar and a maximum temperature of 60°C.
Our view
The GEESEN GK050 stores 50 litres in a narrow 30 cm-wide stainless body and raises the stated element rating to 2,000 W. Its package is more explicit than several TESY listings because it names a safety valve, drip pipe, hanging plate and screws, while the title says UK plug. That reassurance is limited by the included American NTP 1/2 adapter, which means the plumbing connection still needs checking against the intended UK installation. The listing says energy class A but gives no load profile, so it cannot be treated as a measured saving against the TESY class C figures. Its 3.5-star average from 17 ratings is modest, with UK reviews mentioning a missing thermometer, a crushed top and the circular case as well as useful hot water. At about £219, it is a possible compact alternative when the included valve matters, though its 55°C maximum and mixed quality reports count against it.
Pros
- Readable 2,000 W rating for a 50 litre store
- Safety valve, drip pipe and hanging plate listed in the box
- Narrow 30 cm stated width
- Title states a UK plug
Cons
- American NTP 1/2 adapter complicates the plumbing claim
- Only 3.5 stars from 17 ratings
- UK reviews mention missing or damaged parts
- Energy class A lacks a stated load profile
Best for: A compact 50 litre installation where the installer verifies the plug, pipe adapter, maximum temperature and supplied safety valve.
Less suitable: Anyone wanting strong review evidence, a clearly comparable energy label or a conventional UK compression connection straight from the box.
Specifications
- Model
- GEESEN GK050 50 litre
- Brand
- GEESEN
- Price
- ∼£219
- Customer rating
- 3.5/5(17)
- Type
- Direct electric
- Capacity
- 50 litres
- Power
- 2,000 W
- Max temperature
- 55°C
- Energy class
- A
- Supply
- UK plug stated
- Valve in box
- Yes
- Empty weight
- 14.9 kg
- Size
- 30 × 60 cm
Common questions
Is a safety valve included?
Yes. The included-components line lists a safety valve, plus a drip pipe, a hanging plate, screws, instructions and an American standard NTP 1/2 adapter.
Does the listing say it has a UK plug?
The title says UK plug. A bullet says a standard 240-volt connection. The same contents list includes an American standard NTP 1/2 adapter, so the pipe fitting is not a UK compression fitting on that line.
What did UK reviews report?
Among six UK texts: water got very hot in an office; a thermometer was missing; one unit arrived with a crushed top; the case is circular and the wall has to carry the filled weight.
Our view
The TESY BiLight 50 litre horizontal is the clearest low-cupboard option for one person in this set, with a stated 1,500 W element and a 1 hour 18 minute heat-up from 15°C to 60°C. Its 81 cm width and 38 cm height can solve a placement problem that a tall cylinder cannot, while the about £159.99 price sits close to the smaller 30 litre model. The listing specifies a 16 A fused spur, so this is not a normal 13 A plug-in appliance and the electrical work needs planning. It includes a wall bracket but not the fixing bolts, leaving the installer to match the fixings to the wall and the filled load. There is no customer-rating line in the captured listing, so reliability cannot be inferred from stars. It is our best-value pick when horizontal mounting and 50 litres are the brief, but not when several people need consecutive showers.
Pros
- Horizontal 50 litre format at about £159.99
- Readable 1,500 W rating and stated heat-up time
- Load profile M and annual energy figure disclosed
- Wall bracket included
Cons
- Requires a 16 A fused spur
- Fixing bolts are not included
- No customer-rating line in the captured listing
Best for: One person with limited cupboard height who needs a modest direct store and can arrange the stated fused spur.
Less suitable: A family, a normal plug-in installation or a wall whose filled-load capacity has not been checked.
Specifications
- Model
- TESY BiLight 50 litre horizontal
- Brand
- TESY
- Price
- ∼£160
- Type
- Direct electric
- Capacity
- 50 litres
- Orientation
- Horizontal
- Power
- 1,500 W
- Max temperature
- 65°C
- Max pressure
- 6 bar
- Energy class
- C
- Supply
- 16 A fused spur
- Heat-up
- 1 h 18 min
- Empty weight
- 17 kg
- Size
- 81 × 38 cm
Common questions
How is this one meant to be mounted?
The listing describes a 50 litre horizontal wall heater for places where a vertical unit will not fit. Item size is 81 cm wide by 38 cm high.
What electrical supply does the listing ask for?
A bullet says it requires connection to a 16 A fused spur. It does not describe a 13 A plug.
What energy figures are printed?
Energy class C, load profile M, and 1,418 kWh a year. It also states 1,500 W and a heat-up of 1 hour 18 minutes from 15°C to 60°C for 50 litres.
How we compared
We compared the six direct electric wall cylinders kept from amazon.co.uk listings captured on 16 October 2026. Larger merchant cylinders are a different product and are not scored here. Weights follow heat source, capacity, a readable element rating, the safety parts in the box, and price. There was no laboratory test. The five weights sum to 100.
1
Capacity for the household
25%Litres against the Hot Water Association rule of thumb of 35 to 45 litres of stored hot water per person. A 30 or 50 litre wall store is not scored as a family cylinder.
2
Readable element power
20%A wattage is used only when the listing prints a domestic figure you can compare. The 1,500 kW and 220 W lines are left blank.
3
Safety kit and supply
25%What the box actually contains, the stated relief parts, and whether the listing asks for a 16 A spur, a cable, or a plug that still needs checking.
4
Listing clarity
15%Points come off when capacity and the model code disagree, reviews are copied across sizes, or an energy class has no load profile.
5
Price in this set
15%Shelf price on the captured amazon.co.uk listing, from about £139.99 to £259.99. A lower price does not offset a store that is the wrong size.
Independent review
Last updated: 17.10.2026
8 sources checked
Hot water cylinder buying guide
These six listings are direct electric wall stores. The useful comparison is litres, a wattage you can read, and the parts that are actually in the box. A family cylinder, an indirect coil and a heat-pump store are different products.
What is a hot water cylinder?
A hot water cylinder stores heated water for taps and showers. It is vented, fed from a cistern, or unvented, held at mains pressure with relief valves and a visible discharge. It is direct, with an immersion heater, or indirect, with a coil from a boiler or a heat pump. Vertical suits a tall cupboard. Horizontal suits a low one. The TESY 50 litre and 100 litre listings are the horizontal models in this set. A UK review says the GEESEN case is circular.
Best for
- A flat without gas or a loft cistern, where a 30 to 120 litre direct wall store is the right size
- One person with a low cupboard who can arrange a 16 A fused spur
Not ideal for
- A home that needs an indirect coil from a boiler or a heat pump
- A household treating 30 or 50 litres as a full family cylinder
Mistakes to avoid
- 1
Treating one star line as three tests
The 30, 80 and 120 litre TESY files share 4.4 from 72 ratings and the same written reviews. That block does not prove three sizes separately.
- 2
Quoting a broken watt line
The 80 litre file prints 1,500 kW and the 120 litre file prints 220 W beside 220 V. Leave both blank. Use only the 1,500 W, 2,000 W and 3,000 W figures that read as domestic elements.
- 3
Assuming the valve is included
The 100 litre listing is cylinder only and requires a 3 bar temperature and pressure relief valve. The 50 litre horizontal does not include fixing bolts. The word unvented on a title is not a commissioned installation.
What to weigh up
Heat source and capacity
HighEvery listing in this set is direct: an immersion heater, not a coil. Choose direct when electricity is the only heat. Choose indirect when a boiler or a heat pump will heat a coil. A home with a system boiler needs that coil, and this basket does not contain one. Heat-pump cylinders are larger-coil indirect stores. A City Plumbing rule of thumb, citing MCS, is about 45 litres a person below 10 kW. That product is not here. Capacity is the next cut.
Power, valves and the supply
HighElement power counts only where the listing is readable. The 30 litre and the 50 litre horizontal TESY state 1,500 W. The 50 litre horizontal also states 1 hour 18 minutes from 15°C to 60°C, load profile M and 1,418 kWh a year. The 100 litre horizontal states 3,000 W. The 80 litre file prints 1,500 kW and the 120 litre file prints 220 watts beside 220 volts. Do not use those two figures, and do not estimate a recovery time from them. Then the box, the wall and the electrics.
Which option suits you?
Three typical situations, each with a recommendation from this comparison.
One person, low cupboard
You have room that is wide rather than tall, and you can arrange the stated 16 A fused spur. Fifty litres is a one-person store, not a family cylinder.
Valve listed in the box
You want a 50 litre store whose contents line names a safety valve, and the installer will check the UK plug claim, the NTP adapter and the 55°C maximum.
Common questions about hot water cylinders
Which hot water cylinder is the top pick in this comparison?
In these six amazon.co.uk listings, the top pick is the TESY BiLight 30 litre at about £139.99. The listing states 30 litres, 1,500 W and energy class C. It is the smallest store here, so it fits a sink or a short draw, not a family. The 4.4 from 72 ratings on this listing is the same line as on the 80 and 120 litre TESY files, so it is not a separate test of the 30 litre size.
Which listing is the best value?
The best value in this set is the TESY BiLight 50 litre horizontal at about £159.99. It states 1,500 W, a heat-up of 1 hour 18 minutes from 15°C to 60°C, load profile M and 1,418 kWh a year. It needs a 16 A fused spur, and fixing bolts are not included. The captured listing has no customer-rating line, so stars are not part of the reason.
How much do these hot water cylinders cost?
On the 16 October 2026 amazon.co.uk capture, the wall stores run from about £139.99 for the TESY 30 litre and about £159.99 for the TESY 50 litre horizontal, through about £219 for the GEESEN 50 litre and about £234.99 for the TESY 80 litre, to about £254.99 for the TESY 120 litre and about £259.99 for the TESY 100 litre horizontal. A 180 litre merchant cylinder is a different product and a higher price.
How many litres should a hot water cylinder hold?
The Hot Water Association’s rule of thumb is 35 to 45 litres of stored hot water per person. A 50 litre wall heater is not a family cylinder. Showers and reheat change how far that store goes, so litres alone do not size a home. These six listings only illustrate how small a 30 to 120 litre wall store is. They are not a sizing table for a whole house.
Should you buy a direct or an indirect cylinder?
Choose direct when electricity is the only heat, which is every listing in this set. Choose indirect when a boiler or a heat pump will heat a coil. None of these six describes a coil. A home with a system boiler needs an indirect cylinder, and a heat-pump owner needs a suitable coil, not a small direct wall store. That choice is separate from vented or unvented.
Do you need an installer for an unvented cylinder?
CNC Building Control says an unvented store over 15 litres needs a competent person. The Hot Water Association says a scheme member can self-certify. In England, Approved Document G requires at least two independent safety devices besides the thermostat, and a visible, safe discharge. The word unvented on a listing is not G3 approval, and you do not commission the valves yourself. The unvented or vented guide covers the pressure choice.
Why do three TESY sizes share the same star rating?
The 30, 80 and 120 litre TESY listings each state 4.4 from 72 ratings, and the written reviews in those files are the same texts. Treat that as one shared block, not as three tests. The 100 litre horizontal states 3.6 from 7 ratings, with no review text captured. The 50 litre horizontal has no customer-reviews line in the capture. The GEESEN states 3.5 from 17 ratings.
Is a 30 litre cylinder the same as a point-of-use heater?
A 30 litre wall store can serve one outlet, but it still stores water and still needs the electrics and the relief parts checked. A point-of-use water heater is a separate comparison for heating at a single tap. Do not read class C on the TESY label as a failed product. On load profile M, class C is a defined band, and class A on that profile starts much higher. The GEESEN states class A with no profile, so the two labels are not a measured saving.
Our verdict
In this set of six amazon.co.uk wall stores, the top pick is the TESY BiLight 30 litre when 30 litres, a readable 1,500 W element and about £139.99 are the brief. It does not cover a family. The best value is the TESY BiLight 50 litre horizontal at about £159.99, with a stated heat-up, when the cupboard is low and one person is the load. Skip both if you need an indirect coil, or if the listing you are reading hides the wattage or the valve.
Best overallView offer
TESY BiLight 30 litre
Clear 30 litre capacity, a readable 1,500 W element and the lowest price in this set, at about £139.99. The shared 4.4 from 72 ratings is not treated as a separate test of this size.
Best value
View offer
TESY BiLight 50 litre horizontal
Horizontal 50 litres at about £159.99, with a readable 1,500 W element and a stated heat-up. It needs a 16 A fused spur, and the captured listing has no star line.
Editorial
Editor, DIY & tools
Hot water cylindersDirect electric storesamazon.co.uk listings
Peter F. is the editor for DIY & tools at productscompared.co.uk. Comparisons in this category are checked against amazon.co.uk listings, review evidence and public UK sources.
Updated: 17.10.2026
8 sources checked
Guides to hot water cylinders
Guides on what to look for, how to use a product, and common mistakes.
Hot water cylinder buying guideWhat to decide before you buy, without an ASIN ranking.Best hot water cylinderWhich of the six listings fits, and who should skip each one.How to size a hot water cylinderThe 35 to 45 litre rule of thumb, showers and reheat.Unvented or vented cylinderMains pressure, the cistern, and when you need an installer.Direct or indirect cylinderImmersion heater or a coil. This set is direct.
Related comparisons
Sources
Public UK sources listed in the research digest, and the amazon.co.uk listings for these six cylinders. Prices in the digest were captured on 16 October 2026.
- Approved Document G (2024 amendments) (retrieved 16.10.2026)
- Part G FAQ (retrieved 16.10.2026)
- CNC Building Control: unvented hot water cylinder (retrieved 16.10.2026)
- Hot Water Association, unvented note (retrieved 16.10.2026)
- Hot Water Association, sizing a hot water cylinder (retrieved 16.10.2026)
- HSE: legionella and hot and cold water systems (retrieved 16.10.2026)
- Regulation (EU) No 812/2013 on legislation.gov.uk (retrieved 16.10.2026)
- TESY BiLight series (retrieved 16.10.2026)
This article contains affiliate links. If you buy through these links we may earn a commission at no extra cost to you. Prices and review counts come from amazon.co.uk listings and public UK sources. We did not run a laboratory test.