With the current emphasis on building efficiency solar hot water systems are pretty much a standard option if not automatically included.
These systems incorporate either gas or electricity boosting for cloudy days.
Here are a few thoughts on the options for solar hot water:
Split System or Tank On Roof
- Systems with Tanks on the roof are the most efficient . They don’t need a circulation pump to circulate the hot water to the storage tank and don’t have long pipe runs that lose part of the heat you have collected. If this is the way you decide to go make sure your roof has been designed to take the load.
- Split systems are easier to service when they go wrong as everything other than the panels is at ground level. Many people also prefer the look as they don’t like the large tank on the roof for aesthetic reasons.
Flat plate or Evacuated Tube Panel
- Evacuated tube systems are more effective. Also from comments on forums I hear 2mm evacuated tubes are stronger than flat plate collectors in the case of large hail, and are less likely to be hit square-on, due to their shape. Just make sure you aren’t getting cheap quality thinner walled tubes.
- Modern good quality evacuated tube and flat plate systems should be essentially maintenance-free. Just make sure of the quality, it can cost $300-$400 in labour to replace a defective panel even if the actual panel is replaced under warranty.
Some of the early Solar water systems only insulated the hot water coming from the system. This is poor practice as once the system starts running the water from the storage tank back to the panels warms up. If this cools in the pipes to the panels you will be loosing efficiency. Make sure you have all pipes insulated.
- I think Gas Boosting is probably the best way to go even if you have the higher priced bottle gas rather than mains gas. This is because gas systems only boost the water when you want it rather than electricity where you are heating the whole tank up even if you are only using 10% of the contents.
- If you `go for electricity its best go for an off peak boosting, but only switch it on if the forecast is for cloudy weather.
See why a West Roof Mounting may be worth thinking about
For more information on choosing systems for your new house see ‘Selection / Pre-Start Guide’