translation.en: But you can use it to optionally heat hot water and that brings the efficiency up even higher because some of the heat that you would normally be rejecting, you can now use as useful energy, whether it's for a pool or hot water.
translation.zh: 但是你可以选择使用这热水， 这将是效率进一步提高， 因为不用的话就损失那一部分， 可以用在游泳池或是热水。