Med to High
Solar water heating is a really worthwhile investment - it is energy-eﬃcient and has low running costs. It will add an additional $5,000 to $10,000 to your build costs, depending on the size of system that you require. However, a well-installed system will typically save you 70% on your annual water heating bill.
Because solar energy is variable, a booster system or wetback is required to provide reliable water heating, particularly in the winter.
Another very eﬃcient option that is well worth considering is a heat pump hot water system. Heat pumps are the most eﬃcient electricity-based option for heating water and are comparable to solar water heating in terms of energy eﬃciency.
As with solar water heating, it is common to include an electrical heating element to supplement the heat pump. This is because they tend to work less well in lower outdoor temperatures, such as those experienced in the coolest parts of the South Island during winter, although they are improving all the time.
If you have a building site that doesn’t get a great deal of direct sun, a heat pump may be the ideal choice for heating your water. They are also an excellent option for heating large amounts of water for an underﬂoor heating system, a spa or a swimming pool.
However, if you have a smaller household of one or two people, and don’t use a lot of water they may not be the best solution. You also need to factor in the placement of the exterior unit as they can be rather noisy.