When it comes to heating your pool’s water, there are two different types of system you can use: primary and secondary.
A primary system allows the bather to set the thermostatic controls at a specific temperature – typically between 22°C and 30°C. The heating system will then operate up to and until the water reaches that desired temperature, irrespective of external factors (i.e. ambient temperature, weather, sunshine, etc.)
A secondary system will raise the water temperature, but is dependent on these external factors. Secondary systems generally cannot guarantee the pool water will reach the desired temperature and, as such, are often installed as a back-up to primary systems.
When used in combination, a primary and secondary system can offer considerable savings on running costs. This is because the secondary system will kick in when external factors are in its favour, and the primary system will take over when they are not.
Air-source heat pumps provide a good example this. When the weather is good and the ambient temperature is relatively high, these heat pumps work very efficiently as a secondary system. However, when the weather is poor and the ambient temperature is a lot cooler, the heat pumps do not work as effectively. To combat this, a gas heater (primary system) can be used to ensure the desired temperature is reached.
