Boosting Water Pressure and Flow in an Air Source Heat Pump (ASHP) Hot Water System

As the focus on sustainability increases and more grants become available, many homeowners are choosing to install air source heat pump (ASHP) systems as an alternative to conventional boilers. ASHPs help reduce CO₂ emissions and lower energy bills. In most cases, an unvented hot water cylinder is installed alongside the ASHP, allowing it to heat and store hot water for the household.
However, homeowners often experience disappointing water performance when running a bath or taking a shower. Instead of the powerful flow they expect, they may end up with a weak trickle, especially when multiple outlets are in use at the same time. This is because the system relies on the mains water supply, which can vary in pressure and flow throughout the day.
Low mains water pressure and flow may also be insufficient for supplying an unvented cylinder, which typically requires around 1.5 Bar at 20 L/min (check the manufacturer’s instructions). Without adequate supply, the ASHP system may be hindered or unable to run effectively.
The good news is that TankBoost by Salamander Pumps provides a reliable solution. Designed to boost mains water pressure and flow, TankBoost is suitable for use with ASHP systems paired with unvented cylinders.
TankBoost can deliver improved water pressure and flow to multiple outlets across several floors simultaneously. It is a compact, all-in-one unit combining a cold water storage tank with an integrated submerged pump. A range of tank sizes is available, along with 3.0 Bar and 5.0 Bar options, and flow rates of up to 80 L/min or 120 L/min, depending on the property’s water demand.
TankBoost will ensure you get the best water performance from your shower(s), taps and other appliances within an ASHP system.

See example installation diagram below: