Skip to content
The Pool Heating ChickSize my pool

Advice · 4 min read

How long does it take to warm a pool?

Warm-up is a volume problem first and a heater problem second.
All advice

Written by Belinda

Last updated:

The short answer

Warm-up time is roughly the energy needed to lift your pool's volume by the required degrees, divided by the heater's effective output after heat losses. For typical domestic pools and heat pumps it is measured in days rather than hours.

In this guide

The physics in one line

Water needs about 1.16 kWh to warm 1,000 litres by 1 °C. A 48,000 litre pool lifted 8 °C needs roughly 445 kWh before any losses. Divide by the heater's real output (minus what the pool is losing at the same time) to get hours.

What slows it down

  • Cold air reducing heat pump output
  • Running without a cover during warm-up
  • Short filtration run times, because the heater only works when water flows
  • Wind and overnight radiation

Practical tips

  • Start warm-up before the weather turns, not during a cold snap
  • Keep the cover on during warm-up
  • Run filtration long enough for the heater to work
  • Then maintain temperature rather than reheating from cold

Keep reading

Heating a pool through an Australian winterWhat temperature should you heat a pool to?

General guidance from The Pool Heating Chick. It is not a substitute for advice about your specific site.