Do Heat Pump Water Heaters Need to Be Vented?
Do heat pump water heaters need to be vented? Heat pump water heaters need access to a suitable supply of air, but they do not always need to be vented or ducted outside. An integrated air source heat pump water heater can often take air directly from the room where it is installed and discharge the cooler air back into the same space, provided the room meets the manufacturer’s minimum air volume and ventilation requirements.
Does a heat pump water heater need outside ventilation?
Not necessarily. In a sufficiently large utility room, garage or plant room, an unducted heat pump water heater may be able to use the surrounding air.
However, the heat pump extracts heat from this air. The discharged air is therefore cooler, which can gradually reduce the room temperature.
In a small cupboard or enclosed space, the temperature can affect the heat pump’s Coefficient of Performance (COP) and increase hot water recovery time.
Can the air be ducted?
Yes, many heat pump water heaters allow ducting to be connected to the air inlet, exhaust or both.
This feature can allow the heat pump to:
- Take air from another suitable area
- Discharge cold air elsewhere
- Use outside air if the model is designed for it
- Operate when the cylinder is installed in a smaller room
Duct diameter, maximum length and the number of bends should follow the manufacturer’s instructions, as restrictive ductwork can reduce airflow and performance.
Please see the following webpage for these details of our heat pump water heater range:
100 Litre wall-hung heat pump water heater
200 and 300 litres floor mounted heat pump water heaters
400 and 500 Litre commercial heat pump water heaters
What about an unvented hot water cylinder?
The word “unvented” has a different meaning when referring to the cylinder itself.
An unvented heat pump water heater stores domestic hot water under mains pressure and does not require a traditional cold water storage cistern. This is separate from the ventilation or ducting required by the heat pump.
Our unvented heat pump cylinder range is detailed here
In short, a heat pump water heater needs adequate airflow, but it does not necessarily need an outside air vent. The correct arrangement depends on the appliance, room size and manufacturer’s installation requirements.