Return on investment
Real figures on a 1.5Kw and 3 Kw typical install

Some quick numbers on payback time
for two different size PV systems

Payback period for a 3kW Solar PV system  

System Cost $8,500 fully installed (typical current retail price)
Electricity current purchase price based on 20c per KW with an estimated increase of 20% per year
Based on current feed in tariff of 44 cents (QLD)
System produces 15kWh per day based on an average system using REC panels
@ 50% Export , 50% used in house (typical estimate)

Power savings over 5 years
1st year  $1631
2nd year $1730
3rd year $1850
4th year $1993
5th year $2168

Total production after 5 years with an average 50% export= $9372

Payback period for a 1.5kW solar PV system

System Cost $5,000  fully installed
System produces 7kWh per day
@ 50% Export, 50% used in house
Same buy prices of electricity and feed in tariff as the 3KW PV system above

Power savings over 5 years
1st    year  $ 810
2nd   year  $ 864
3rd    year  $ 919
4th    year  $ 989
5th    year  $1077

Total production after 5 years at 50% export= $ 4660
6th year = $5839