Residential Solar Power Systems - A Buyer's Guide

Tammi R

The average homeowner in Australia uses approximately 18 kWh of electricity per day. Homeowners in Australia and New Zealand are rapidly moving to this greener means of electricity production. Costs of installing a residential solar power have dropped while capabilities have increased. Rising charges for electricity provided by power companies and government incentives provide motivation. The ability to continue to use regular electricity at night while selling unused solar power to the power companies during the day provides flexibility. What is more, solar power is friendly to the environment.

 aust energy price rises

Rising Electricity prices in Australia over the past 5 years are a key driver of solar power uptake.

Solar panels, also known as photovoltaic or PV panels, create DC electricity from the sun's rays. These panels can be mounted on the roof, built into the roof as part of the roof covering or attached to a freestanding rack that moves with the sun. The electricity is carried from the panels through heavy cable to an inverter. The inverter converts DC electricity to AC to supply power for the house.

Solar Panels

The three basic types of solar panels are monocrystalline, polycrystalline, and thin film. Monocrystalline panels were the first to be developed and take less space to install than polycrystalline panels. Both polycrystalline and monocrystalline panels are made of silicon. They degrade at an extremely low rate of between 0.25 and 0.5 per cent per year.

Thin film panels or solar tiles may be made of silicon, cadmium telluride or copper indium gallium selenide. If your roof is tiled, you can incorporate the panels as part of the tiling. The electricity produced by thin film panels does not decrease when the panels get hot, and they hold up well. However, initial costs are high.

 three types solar

To determine how many panels you need, figure out how many watts it takes to run everything in your home. If you currently pay for electricity, look at your bills for the last 12 months. Find the statement that shows the most power used. If you want your system to supply all your electricity, increase the total number of kilowatt-hours or kWh, by one-third. Size your system to meet that demand. Any reputable solar company will be able to help you with this calculation.

Only buy solar panels from a company that has a solid reputation for workmanship and quality. Make sure the company upholds its warranties and that there is a stable contact in your area. It is extremely difficult to enforce warranties made by companies that do not have a local or regional presence. Imagine shipping solar panels back to China for repair or replacement. It would cost a small fortune!

Where possible, it’s wise to avoid cheap solar panels manufactured in China. There is a higher chance of defects in workmanship and power output can often be less efficient. The market is flooded with Chinese PV panels but it doesn’t mean you should take the cheapest option.

Another good tip is to check panel power tolerance ratings. Solar panels vary in the amount of current they produce. The rating, given in watts, shows how much DC power the panel can be expected to generate under standard conditions in full sunlight. Panel specifications also list power tolerances. This specification shows how much variation there might be with regard to the wattage output rating. A panel rated at 250 watts with a tolerance rating of -4/+5% might produce only 240 watts instead of the expected 250. To ensure that you get the power you expect, be sure to only buy solar panels which have positive power tolerance ratings.


You don’t want to go cheap on the inverter as it’ll often be the first item to fail on you – and they can be expensive to replace. The type of inverter you need depends on what you want your solar power system to do. If you plan to continue to use electricity from the grid at night, look for an inverter that produces pure sine wave. If you are going to store electricity, look for an inverter with a built-in battery charger. Your inverter should have ground fault, reverse polarity and surge protection. Some inverters come with built-in meters to provide valuable information regarding power input, output and inverter


Inverters are sized according to maximum output power and AC output voltage. Choose a model that works with the voltage requirements of your appliances. Make sure that your inverter is large enough to run everything in and for your house simultaneously. Water pumps, electric stoves, microwave ovens and coffeemakers pull a lot of electricity.

Insist on an inverter built by a reputable manufacturer. Make sure the inverter is solidly backed by the manufacturer's warranty. When you buy an inverter, you want one that will stand up to hard use year after year. Cheap inverters do not hold up well.

Roof Mounting System

If you choose to mount your solar panels on the roof, do not scrimp on the roof mounting system. The system needs to be constructed so that it will hold the panels securely in place in all types of weather. Frames made of aluminium or stainless steel are best. They do not corrode. If the added weight of solar panel framing is a concern, choose aluminium. For a solar panel system that will be subjected to high winds, choose a frame with a low profile.

 solar panel mounting

5 Must-ask Questions for the Solar Salesman

1. What information do you need to be able to recommend a complete solar system?

A salesman who is knowledgeable will ask about location, roof type and pitch, whether you want a system to replace grid power or work in coordination with it, and the home's current power consumption. He also may ask about your budget.

2. Are you willing to visit my home before I buy from you?

Because the salesman and the installer work together, a reputable salesman should not be reluctant to visit the site.

3. Could you give me the names of satisfied customers?

An established company is happy to let you talk with homeowners who already have systems that the company installed. They are proud of their work, and the customers are proud of their systems.

4. Are you an accredited designer and installer?

Homeowners are not eligible for government rebates unless the designer and installer of their solar power systems are accredited by the relevant clean energy council in your country.

5. If something goes wrong after my system is installed, what help can I count on from you?

The company you buy from should be willing to assist, both by phone and on site. Warranty help also should be provided.

This article was written by the team at Infinite Energy, a solar power company with offices in Perth, Brisbane, Gold Coast and Sunshine Coast.

1 comment

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Kelly Rogers (anonymous)

Thanks for telling us about the 3 kinds of solar panels. I thought there were only 2: solar panels and thin film solar. Now I know. :)

Written in August 2013

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  • Posted on June 14, 2013. Listed in:

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