Solar Water Heating FAQ Wellington

Solar Water Heating FAQ Wellington

Solar water heating is a method of using sunlight to heat water with the help of solar thermal collectors. This heated water is then stored for use in insulated hot water tanks. Solar water heaters are efficient but sometimes may require external energy boosters if sunlight is not enough.

Solar hot water heating image of evacuated tubes installation in wellington

Solar Water Heating Frequently Asked Questions

Are Evacuated Tubes better than Flat Plate?

Tubes are slightly more efficient, particularly U tube types. Flat plate is less likely to be damaged by hail or stones. Evacuated tubes are more efficient in winter and later in the afternoon. Flat plates are usually better at midday.


Can I use my existing tank?

Tank size depends on the number of people consuming the supplied hot water.  1 person = 135 litre, 2 people = 180 litre, 3 people = 225 litre, 4 people = 250 litre, 6 people = 300 litre.  If your tank has that much capacity, that will be fine. If not, a smaller collector will be used and the installation will not meet your daily needs. With solar water heating, the daily hot water requirement needs to be collected between sunrise and sunset.

Some tanks have heating limitations eg max 70’C so the solar collector controller is set to no more than that.  Specialist solar tanks often have higher limits.


Does the pump need much power?

Pump usually needs around 15 to 35 watts when it is running. The pump runs when the sun has heated the collector.


Are we approved EECA installers?

Yes, Southern Plumbing is EECA approved installer.


What happens if the power is turned off?

The pump stops working. The controller will restart when the power is turned on.

There are some solar installations where the collector is below the tank where convection can occur between the collector and the tank. So no power is required.


Can I have solar water heating when my roof faces east or west?

Not for best results. Sometimes we can put them on the northwest side. .


Can I have solar water heating if my collector area is half shaded?

No, it is difficult to collect enough hot water to repay the installation.


What maintenance is needed in solar water heating?

Wash the collector once per year, check the pipe insulation, check the pump is operating, change the glycol if your system has it, not many do. Check plumbing for leaks, if the system is closed loop check it still has pressure on the pressure gauge. Lastly, check the roof fixings.


Who Can Install a Solar Water Heater Plumbing?

A licensed Master Plumber can install solar water heaters. We are a certified plumbing company in Wellington, you can contact us for installing solar water heaters in your premises.


What Happens in the Winter?

Solar water heaters don’t get as much sun as needed, but will heat the water from cold to about 30-40 degrees depending on whether the collector has been correctly sized. The collector will heat water even when it has been raining all day.

Call during working hours for further questions  04 384 4635