The Quality Heating QH Dual 80 Litre Horizontal Electric Water Heater is a large-capacity, wall-mounted storage cylinder designed specifically for horizontal installation - perfect for low-ceiling utility rooms, cupboards under stairs, or any space where a tall vertical cylinder won't fit. It offers three selectable power settings and Energy Class B efficiency.
The defining feature of this model is its horizontal-only mounting configuration. Unlike standard cylinders that must stand upright, this unit is engineered to lie on its side, with the hot water outlet correctly positioned at the top. At 80 litres stored capacity, it delivers approximately 142 litres of usable blended hot water per cycle once mixed down to a comfortable 41°C delivery temperature - comfortable for 1-2 occupants.
800-2000W
Selectable Power
Horizontal Mounting: Outlet Must Face Upward
This is a horizontal-only unit. When installed, the hot water outlet connection must face upward. This is essential for correct thermal stratification and to prevent air locks - installing with the outlet in any other orientation will reduce efficiency and may cause noise or erratic operation.
Usable Water Yield is a Calculated Figure
The 142L figure is a theoretical maximum, based on a stored temperature of 65°C, a 10°C cold mains feed, and blending down to a 41°C delivery temperature - the same reference point used across the QH range for comparability. In practice, horizontal cylinders stratify less cleanly than vertical ones: the hot/cold interface forms across a wide horizontal plane rather than a clean layer, so cold water mixes in sooner during a draw. Expect usable volume in real-world use to run below this calculated figure, and below what an equivalent-capacity vertical cylinder would deliver.
Selectable Power Matches Your Supply
Use 800W to minimise peak load on a limited consumer unit, 2,000W for the fastest heat-up, or the 1,200W middle setting for Economy 7 overnight heating without drawing full load.
↔️ Horizontal-Specific Design
Engineered for horizontal wall-mounting, with the outlet positioned to give the best achievable stratification in a restricted-height space - the practical solution where a vertical cylinder simply won't fit.
⚡ Selectable Power: 800W / 1,200W / 2,000W
Match the power draw to your electrical supply capacity or time-of-use tariff - ideal for properties with limited consumer unit headroom.
💧 80-Litre Stored Capacity
Delivers approximately 142 litres of usable blended hot water per cycle once mixed to 41°C - comfortable for 1-2 occupants.
🔥 Copper Heating Element
Long service life and good resistance to limescale - less maintenance in hard-water areas.
🧭 40mm Foam Insulation
Polyurethane foam insulation (λ = 0.22 W/mK) delivers excellent standby heat retention and low heat losses between draws.
🔒 Six-Level Safety System
Overheat cut-out, thermostatic protection, anode monitoring, and a supplied PRV cover every statutory safety requirement.
| Identification |
| EAN / SKU |
8720986327350 |
| Brand |
Quality Heating |
| Warranty |
2 years |
| Capacity & Output |
| Stored Capacity |
80 litres |
| Usable Hot Water Yield (calculated) |
Approx. 142 litres per cycle, blended to 41°C from 65°C store and 10°C cold main |
| Rated Power (selectable) |
800W / 1,200W / 2,000W |
| Electrical |
| Voltage |
230V / 50Hz |
| Cable Length |
1.5m |
| Electrical Connection |
13A plug (removable for hardwiring) |
| Construction |
| Heating Element Material |
Copper |
| Inner Vessel Coating |
Zirconium-enamel |
| Anode Material |
Magnesium, with audible & visual condition alarm |
| Insulation Thickness |
40mm polyurethane foam |
| Thermal Conductivity (λ) |
0.22 W/mK |
| Energy Label |
Class B |
| Dimensions & Installation |
| Dimensions (W x D x H) |
530 x 280 x 950mm |
| Mounting Orientation |
Horizontal only - hot outlet must face upward |
| Connection Size |
15mm (inlet & outlet) |
| Safety & Compliance |
| Safety Features |
6-level protection; PRV (safety valve) included |
| Controls |
Digital display, adjustable thermostat, illuminated on/off switch, power selector |
| Certification |
CE marked |
Installation & Trade Notes:
This unit is for horizontal wall-mounting only. When installed, the hot water outlet connection must face upward - this is critical for correct thermal stratification and to prevent air locks. The supplied PRV must be fitted and plumbed to a safe, visible, frost-free discharge point in compliance with Water Regulations and Building Regulations Part G.
All electrical work must be carried out by a Part P-registered electrician. Connect via a 13A fused spur or remove the plug for hardwired connection; the circuit must be protected by an RCD. Water connections are 15mm (inlet & outlet). Flush the cylinder before commissioning and set the thermostat to a minimum of 60°C to comply with HTM 04-01 Legionella guidance.
Why is this model horizontal-only?
The internal configuration of the heating element and connections is optimised for horizontal use, with the outlet positioned to make the best of a layout that inherently stratifies less cleanly than a vertical tank. It will outperform a standard vertical cylinder improperly laid on its side, but a correctly installed vertical cylinder of the same capacity will still generally give better usable draw-off, since it stratifies hot and cold water more effectively.
Which way must the hot outlet face when horizontal?
The hot water outlet must face upward. Hot water rises, so the outlet at the top ensures the hottest water is drawn first and prevents air locks. Any other orientation will impair performance.
What are the three power settings for?
The 800W / 1,200W / 2,000W selector lets you match the draw to your electrical supply. Use 800W where spare consumer unit capacity is limited, 2,000W for fastest heat-up, or 1,200W for a good balance, particularly useful for Economy 7 overnight charging.
How much hot water does the 80-litre cylinder produce?
Using the standard reference of a 65°C store, 10°C cold main, and 41°C delivery temperature, the theoretical maximum is approximately 142 litres of usable blended hot water per cycle. Because horizontal cylinders stratify less cleanly than vertical ones, expect real-world usable volume to run below this figure - still generally sufficient for 1-2 occupants for normal daily use.
Is the pressure relief valve included?
Yes - a PRV is supplied and must be fitted and plumbed to a safe discharge point. This is a legal requirement under the Water Regulations.
Can it be used with Economy 7 or solar PV?
Yes. Use a time-switch to charge overnight on off-peak Economy 7 rates, or pair with a solar PV diverter to use surplus generation. The selectable power settings give extra flexibility to balance heating time against electricity cost.
