Solar water heating has some disadvantages over other water heating options.
- It is material intensive and the costs are not avoidable. The panels are a small part of the material cost.
- The work requires a Building Consent. Building Consents are expensive to get and even more expensive to organise. The preparation is where the cost is. Plans specifications, certificates of title, inspections, appointments to apply, tests, smoke alarms, forms to be filled in and posted, compliance certificates, electrical compliance cerficates.
- Its very prescriptive in regard to how the work is to be carried out.
- There is not much flexibility. ie you cannot put the collector on the south side of the house because the sun does not shine there.
- The roof needs to have a minimum area to site the collector.
- The roof cannot be shaded with trees or buildings.
- There is considerable structure that needs to be maintained e.g. insulation, pump, glycol if used. Annual checks.
Compare this to – electrical water heating
e.g. an electric immersion water heater or Heat Pump water heater.
They have none of the above except for the building consent in some cases and the electrical certificate if the installation is new.
Heat Pump water heaters have only two disadvantages they are heavy and need to be away from bedrooms due to the noise. The tank is expensive compared to other water heaters but installation is easy.
