Types of Solar Water Heaters
From a plumbing perspective there are pumped and thermosyphon (or unpumped)
Thermosyphon relies on the tank being above the collector and natural convection moving the water to the tank these types are becoming rare. Often because owners dont want a tank on the roof. Plumbers dont want to install one there either its expensive putting half a ton of tank up there. The installation needs an engineer to determine if the roof can take it.
From a collector perspective there are flat plate and evacuated tube collectors. Tube collectors have the advantage of having a vacuum which makes it harder to get condensation and mildew on the inside of the glass which is what the flat plate collectors suffer from. Freezing is also an issue for flat plate water filled collectors. Freezing is ovecome with either a glycol filled closed loop system or a controller that has a feature to eliminate the problem by starting the pump briefly to get the water moving slightly to stop it freezing.
Differences in Cost
(The First three options are for existing installations)
Types
The existing system has a Supply Tank in Roof – adding a Solar water heater to an existing house using low pressure hot water – is common in NZ.
Roof Mounted tank
The advantace is that the plumbing is short as the collector and tank are together and in the installation is usually mounted over the old supply tank. The existing hot water tank is removed and the hot and cold water are connected to the new tank.
Disadvantage is the cost, difficulty and visibility of the tank on the roof.
Ceiling or ground mounted tank
The collector is on the roof and water is pumped from the collectors down to the tank. Enables the tank to be mounted almost anywhere close by. The disadvantage is heat loss from the piping and pump. Pump and piping cost.
Prices of Solar Installations
The prices below assume that the -
Solar collector is over the hot water cylinder. Roof slope is between 20 and 45 degrees and with in 20 degrees of facing north. Roof slopes outside this add $500. Angles outside 20 degrees of north are not as efficient. Consider repositioning or try heat pump.
Prices include GST
Panel Type Flat Panel Evacuated Tube
Two person $ 6,770 $ 6,670
Three person $ 8,700 $8,370
Four Person $ 9, 370 $ 9,770
Five Person $ 10,770 $ 10,370
Prices subject to checking on site.
