Tillellan – Solar Hot Water System

Finally, we’ve made a decision on how we will be heating our water once the house is renovated

After much research and asking friends about their experiences, some consultation with our local renewable energy guru and some logical thinking, we settled on a Solahart system.

The benefits are that the storage and heating collection is all done on the roof pitch and virtually out of sight. Having to allow for ground floor area to place a storage tank for a heat pump was very limited in the available space we had and would have been a cosmetic challenge. It’s always nice when something works out and doesn’t detract from the appearance of things too!

This set up also means that the Solahart will heat the water within the unit itself, we don’t need to have extra solar pv panels installed to supply energy to a Heat Pump. So we are able to make the most of the roof surface available to us.


The basis for our selection was the argument that using the sun to heat water directly is far more efficient than using a heat pump – which are all the rage at the moment. A heat pump uses electricity – either solar or grid – to act like a ‘reverse refrigerator’ as one solar rep. described it to us. However, the point is that it is using electricity to heat the water and there is energy loss with this process. Some may argue that the heat in the air comes from the Sun anyway, so heat pumps are solar powered, but this process doesn’t hold much logic. Does that mean wind turbines and reverse cycle air-cons in heating mode are solar powered too?

Heat Pumps also work by a thermostat which turns on or off regardless of whether the sun is shining or not and are most likely to do their most heating for hot water in the morning or evening when there is little solar radiation occurring.

The Solahart will store the solar energy as heated hot water in the storage tank (like a battery only cheaper) and only uses the booster as a back-up.

We were concerned about the possibility of having to boost the water to bring it up to temperature through the less sunnier days of the year. We discussed the possibilities of electrical boosting (through our solar pv system) or gas boosting so that we only had water heated as required. Neither of these scenarios needed too much further discussion as the Solahart crew alleviated the concern with their own home system which is wired for electrical boosting (from their solar pv system) and is done so on a timer if ever required to bring the water up to temperature. This scenario though is seldom put into action as the system manages quite well in the local environment.

Our particular system has been installed on the west facing roof pitch where it will get most of the day hours when it counts and finish off with the more intense afternoon sun. There are no impediments to sunlight in that area of the roof from neigbours dwellings or trees etc. The roof is really quite exposed to a decent amount of sunlight during the day. There is also enough space above the Solahart to put in a few solar pv panels and as serendipity would have it, this roof top location is central to the bathrooms and kitchen. The two main areas requiring efficient and quick hot water delivery.

Solahart also have a proven historical record and have improved over the decades as technology has improved. The house I grew up in had a similar system as did my wife’s family house – and aside from some general maintenance over the years both appeared to perform very well.

As with anything related to this house, the Solahart will need some regular attention just to make sure it is working ok. The house is located very close to the coast and will cop some salty winds which can cause materials to erode faster than usual.


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