The argument goes on between these two solar HWS on which is the best value for money and this article identifies the key features and outlines benefits and draw backs of each unit.

 Electric Boost – Solar on the roof, be it panels or evacuated tubes is reliant on exposure to the sun to generate hot water. Two key statements can be made here:

1.       Solar on the Roof heats the water in daylight

2.       Solar on the Roof does not heat water during the night

These two statements identify key usage patterns. If you’re to use hot water in the evening for showering then to ensure you have enough hot water for the morning showers you will require a large storage tank or ensure the booster element is operational during the evening, defeating the object of the solar installation, whether it is energy driven or cost driven.

The heat pump is reliant on the ambient air temperature allowing it to heat 24hrs if required. This enables the unit to produce hot water, when it is required without the use of an electric or gas booster. However, reversing this argument, the heat pumps still use electricity to run the unit, although this only uses a quarter of the amount in comparison to the older electric systems and that of a booster.

1.       Heat pumps can heat whenever

Systems are also tested and perform down to minus 10 degrees and with QLD lowest ever temperature recorded at minus 11 degrees in 1895 and with average winter day recorded between 9 – 20 degrees they is no need for an element.

When comparing these two contrasting styles, both have positive and negative aspects and dependent on your choice of brand will have differing efficiencies. If you have a prime location and the most efficient solar on the roof unit, then you will generate the greatest level of efficiencies and use the least amount of electricity resulting the lowest running costs. Whereas the most efficient heat pumps will come guaranteed with an electricity bill, however it will be extremely competitive with the solar on the roof and during the winter periods is more likely to be lower than the solar cost due to boosting. SOLAR on the ROOF 1 vs 0 HEAT PUMP

Payback Period – This is when the HWS will start to save you money over a more conventional HWS such as an electric or gas unit. This is often a very important aspect when making a decision over units. However a great deal of confusion has been created with different states applying varying rebates, STC’s varying from unit to unit and with the rollback of national rebates. All these factors have inflated the cost of both units and generated a false market. The rebates had previously encouraged the uptake of both solar on the roof and heat pumps, with the opportunity to purchase a unit for less than an electric or gas. However with the rebates having been withdrawn the costs are considerably more than the standard electric and gas and the industry is still seeing these units as premium products when they are not. Solar on the roof has had the biggest challenge as it generates the greatest installation costs, it is difficult to assess the price but for full installation the cost is likely to be $3500 – $5000 for a straight forward installation. In comparison, a heat pump installation is $2000 – $3500. Also to take into consideration on the pricing is the quality of product you are receiving, for the lowest heat pump price you can receive the highest quality product due to economy of scale generated by both Europe and America which have taken on the heat pump over solar on the roof and all other HWS. The Solar on the roof is still a premium based product with a lot of cheap and nasty products available that loose efficiency very quickly.

When comparing the two installation costs of two highly regarded units from both categories the heat pump cannot be matched. Although the Solar on the Roof is likely to generate greater savings, the difference will be insignificant when comparing the payback period. A good quality heat pump installed at a reasonable price, will start to generate savings over a traditional hot water system within 1-2 yrs, where as a Solar on the roof having taken into consideration setup costs will begin to save after 10yrs, which is reliant on the units efficiency and warranty. SOLAR on the ROOF 1 vs 1 HEAT PUMP

These two key features identified make a decision simple, if you have great wealth with the perfect conditions for solar on the roof (North facing roof, no shade, based in QLD) and are interested in purely energy saving and the carbon foot print then the decision should always be Solar on the Roof as it is the most energy efficient HWS.

If you are interested in saving energy and helping the carbon footprint but are also concerned with the cost of running and setting up a unit then there is only one option and that is the heat pump. The majority of homes will find the heat pump most economical, easy and reliable HWS to install. Solar on the roof will suit a few ideally placed and wealthy homes but if you are in doubt then heat pump is the future.

Make the right decision that suits your needs and budget.


By Simon Baird 

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