Wall Mounted Heat Pump Water Heater – 100 Litre
Our wall mounted heat pump water heaters have a storage volume of 100 litres and are air source heat pump water heaters that are wall-hung, compact, and floor space saving units that use an air-source heat pump to produce domestic hot water efficiently, making them a practical option for homeowners looking to cut energy bills and lower their carbon footprint.
100 litre heat pump water heater wall-mounted air source heat pump installations are now very common in flats, apartments, and bedsit applications because of all these features above.
They require electricity to power the air-source heat pump and the optional immersion heater, so installation also needs enough space around the unit for airflow, access, and maintenance.
Heat pump hot water heating system
These heat pump water heaters use an integrated air-to-water heat pump with R290 refrigerant to provide hot water. They are on average 3.7 times more energy efficient than traditional electric immersion water heaters for your hot water needs (up to 5 times depending on outside air temperature), resulting in significant savings on your energy bills and energy use. Our units have an A++ efficiency rating at 20°C and an A+ efficiency rating at an external air temperature of 7°C. They can cost more upfront than conventional water heaters, but the lower running costs are a key part of the long-term value.
This webpage explains how an air-to-water heat pump generates hot water, how the hot water cylinder is built, how heat pump technology affects efficiency, and where it can fit into a renewable energy setup, such as pairing with solar PV panels.
How does an air source heat pump generate hot water?
Domestic hot water air-source heat pumps work by absorbing energy from the air using refrigerated gas that has a low boiling point, and a 100-litre tank is one selection factor when matching the unit to domestic hot water needs. More precisely, the system draws heat from the surrounding air, and the energy is subsequently released as heat when the gas is compressed.
Our domestic hot water heat pumps operate effectively between minus 7°C and plus 43°C, so they work in the cold conditions that we are likely to see in the worst wintertime conditions in the UK and Ireland.
In short, a refrigerant (a substance that changes between liquid and gas as it moves through the refrigeration circuit) absorbs heat from the surrounding air in the evaporator, is compressed to raise its temperature, then releases that heat through the condenser into the stored domestic hot water before the cycle repeats.
So, think of refrigerators, i.e., fridge-freezers; the process is the same, just it’s reversed, and the air-source heat pump releases heat into the water (so it’s an air-to-water heat exchange) rather than an air-to-air process like that used in a fridge-freezer. This process also explains why current systems are generally designed around stored hot water rather than on-demand production. When installed indoors, operation can slightly cool the room and help with dehumidification.
Product detail
Dimensions of the 100 litre heat pump water heater, which is wall-hung/ mounted, which is designated the Aquaflex2 – 100DC
Height: 1,220 mm
Diametre: 520 mm
Empty weight: 42 kg
Electrical supply: 240 volt single phase
Please note that the above data is based on the Europe Average Climate Zone, as defined by the Europe EN16147 regulation for testing domestic hot water heat pumps. This regulation involves an ambient air temperature of 7℃ and heating the water from 10℃ to 53℃. Stage C from EN16147 refers to silent heating mode.
The full details are in the following manual.
ASHP DHW heater product features
- A++ energy efficiency rating at 20°C ambient air temperature and A+ at 7°C;
- Factory-sealed with 150 g of R290 natural refrigerant;
- High-efficiency DC fan motor for reduced electrical consumption and quieter operation;
- Premium 2205 duplex stainless steel hot water storage tank with insulation;
- Provides useful cooling and dehumidification of the air while recovering waste heat for domestic hot water production;
- Built-in Wi-Fi with app control via the Apple App Store and Google Play;
- Wall-mounting brackets supplied with the 100-litre version;
- Magnesium anode for additional corrosion protection;
- External aluminium micro-channel condenser wrapped around the storage tank, helping to prevent scaling within the refrigerant heat exchanger and eliminating direct refrigerant-to-water contact;
- Integrated 1.6 kW electric immersion heater to provide supplementary hot water heating when required, including during low ambient temperature conditions;
- Integrated control panel with LCD touchscreen display on the 100-litre capacity water cylinder model;
- Programmable weekly anti-Legionella sanitisation cycle;
- Fixed or dynamic domestic hot water (DHW) setpoint control for improved energy management;
- External ON/OFF contact switch for solar PV integration, allowing photovoltaic electricity to be used for domestic hot water production for the property or location
Solar PV electricity compatible
Our units are SG Ready (Smart Grid Ready) as standard at no extra cost, meaning our heat pump water heater has an interface that lets an external energy management system, smart electricity tariff, or solar PV system control its operation, so electricity consumption can be shifted to favourable periods and surplus energy can be stored as domestic hot water.
Our next size-up unit is our 200 Litre Air source heat pump water heater. This is a floor-mounting unit only
App controllability – Remotely control your ASHP water heater by a phone or tablet
Our app-controlled heat pump water heaters let you remotely monitor energy use, change water temperatures, and set daily schedules using a smartphone or tablet. It also has diagnostics, so you can receive immediate fault alerts if the system malfunctions.
Air duct installation options
The most common setup is to duct in ambient outside air and duct out exhaust air from and to the heat pump domestic hot water heater.
The intake air and exhaust air outlets are 160 mm in diameter.
The maximum air intake duct and exhaust air duct distance, including a 90-degree bend off the heat pump using rigid ducting, is 10 metres for X and Y in the below diagram; however, if using flexible ducting, this distance is reduced to 6 metres (flexible ducting uses internal support rings or wire helixes that disrupt airflow and create more pressure drop than smooth rigid ducting)
Air exhaust options
The exhaust air from a heat pump water heater (HPWH) is cool and dry, which provides a built-in dehumidification and cooling effect ideal for a laundry room or a wine cellar.
Heat pump technology
These water heaters use heat pump technology to extract heat from the outside air and, via a heat exchanger process, convert it into domestic hot water in a highly efficient manner. Many modern heat pump hot water systems also include Wi‑Fi connectivity and scheduling features, with quiet operation typically falling in the 45 to 60 dB range.
This 100L domestic hot water ASHP uses R290 refrigerant and benefits from a low global warming potential, which helps reduce the carbon footprint by cutting reliance on fossil fuels, as this technology emits no harmful gases compared with fossil fuel systems, with relatively low installation costs when installing a wall-mounted 100 litre heat pump hot water heater.
Hot water cylinder
The hot water cylinder part of the unit is the tank, made out of highly durable premium duplex stainless steel 2205. Installation should be in a suitable room within the property or house with proper ventilation and enough space around the wall-mounted air source heat pump water heater for maintenance.
Renewable energy
The air-source heat pump water heaters use ambient air and electricity to heat the water, so pairing these with solar panels can help reduce reliance on fossil fuels while you generate carbon-zero hot water. Compared with older systems and their energy supply, they emit no harmful gases and heat stored water efficiently. This means you can lower your running costs and save on energy bills by being more energy efficient.
Energy bills
A domestic hot water heat pump reduces your energy bills by using ambient air to create heat instead of generating it via a boiler or electric heating element. A wall-mounted model helps with hot water at a comfortable temperature.
These DHW heat pumps use roughly 75% less energy than a traditional “Economy 7 water heater” or direct electric-fired water heater.
Unlike a full air source unit set outside on level ground, often on rubber feet and needing less space for short pipe runs, this hot-water-only option currently does not qualify under the Boiler Upgrade Scheme like whole-home systems; this is because these units are not designed to replace any heating system or underfloor heating system powered by gas or oil boilers.
Contact us
For further information, check stock availability, lead time, delivery, prices / cost, or to purchase our energy-efficient 100 litre wall mounted heat pump water heater with an integrated air source heat pump range to suit new or retrofit hot water systems from flats, apartments or small houses to even some small or light commercial water heating applications, such as small offices, supplying hot water to staff kitchenettes, hand-wash basins and WCs, small warehouses, retail units, workshops and small industrial units, for staff toilets, washrooms and kitchenettes, as well as beauty salons and treatment rooms, small veterinary, dental or professional premises – for hand washing, cleaning and general domestic hot water use.
They can also be used for holiday accommodation or serviced apartments, where occupancy and shower demand are suitable for the available storage and recovery rate.