10 November • Written By Jarred Nielson

Comparing solar quotes in Tasmania: what to check before the price

Two solar quotes for a Tasmanian home can look alike and still allow for different work. The panels may match while the scope, the warranties, the monitoring or the payback do not. Before you compare the price or the return, check that each quote answers the same question. Lay the written quotes side by side and tick the same items on each one.

A useful comparison brings together the household’s plans, the system design, the full installation and what you receive at handover.

Here is where to start.

1. Write a short brief first

Before you ask for quotes, write a short brief for the household. Include:

current electricity use;
when people are home;
any existing solar equipment; and
changes you are seriously planning.

Separate confirmed changes from possibilities. Each supplier can then quote against the same plans.

2. Give every supplier the same information

Provide bills and interval data where you have them, plus roof information and known constraints. Ask each supplier how they assessed shading and orientation, and what assumptions sit behind the generation estimate.

Panel capacity, inverter capacity and permitted export are different figures. Do not treat them as interchangeable. Ask the supplier to name each one and explain the proposed arrangement. Keep the connection requirements and any limits in the written scope.

3. Check that each written quote lists the same items

The Australian Government’s guide to choosing a solar retailer and installer says to get quotes from at least 3 suppliers and ask for a site visit.¹ To compare like with like, it says quotes should show:

how long the quote is valid;
the size of the system in kW;
the make and model of the solar panels;
the inverter or microinverters, and the battery if one is included; and
details of warranties for installation and for the system components.

The same page says there is more to consider than price when comparing quotes. If an item is missing, ask for it in writing before you compare.

4. Compare the return as well as the price

The Australian Government’s guide says a solar quote should show the total cost, with any government rebate deduction shown clearly, a breakdown of equipment and installation costs, the expected electricity output or the estimated monthly and annual savings, and an estimated payback period. The output and the savings have to show the assumptions used.¹

On these quotes, that payback period is the return on investment. Read the cost, the estimated saving and the payback as three separate lines. Compare the payback only when both quotes use the same household demand, the same import prices and export credits, the same period, and the same assumed changes in use.

Ask how the proposal splits generation between use in the home and exports. If a battery is included, ask how it will operate and what it costs, on its own line. A future EV should not be treated as a current daytime load, especially if the car will be away during solar hours.

The same page says a network limit on system size or exports can change the financial benefit. Ask how a limit would change the estimated saving and the payback.

A headline annual saving is difficult to assess when the household demand behind it is missing. A shorter payback is not comparable when one quote leaves out part of the installation, or the two quotes assume different tariffs or different daytime use. The payback estimates how long later savings take to cover the cost. It does not make that money available on the day you pay.

5. Compare the full installation

Check whether each quote includes:

access;
mounting;
switchboard work;
monitoring;
commissioning;
removal of old equipment; and
any identified approvals.

Ask what would lead to a variation, and get the answer in writing.

6. Read the product and installation warranties separately

The Australian Government’s warranties page says a product warranty covers faulty products. A workmanship warranty, sometimes called an installation warranty, covers issues from the installation of your solar power components.² The page also describes a separate performance warranty for solar panels.

These kinds of cover address different things. The length of one does not describe the scope of the other. Confirm who will handle an issue, and what records you receive at handover.

7. Ask what the monitoring will show

The Australian Government’s monitoring page says a string inverter with monitoring shows how much electricity the total system is generating, typically for the current day only. It does not show how the system is operating over time, or how you are using the electricity it generates. Further monitoring can show your total electricity use, electricity bought from the grid and solar exported to the grid. Monitoring can be added later, but the page says it is cheaper to include it when the system is installed.³

If you want to see household use and grid flows, ask whether that measurement is in the quote.

8. Resolve the differences before you choose

Put the proposals side by side. Ask each supplier to explain the differences.

A lower price may reflect a different system or a missing item. A larger system may or may not suit the household’s demand and plans. Look for a design that fits, a complete scope, and assumptions you can follow.

Frequently asked questions

What should I give each solar supplier before they quote?

Give every supplier the same information: bills and interval data where you have them, roof information and known constraints. Add a short household brief covering current electricity use, when people are home, any existing solar equipment and changes you are seriously planning. Separate confirmed changes from possibilities.

How do I compare the return on two solar quotes?

Use the estimated payback period, and only when you can see the total cost, any rebate deduction, and the estimated saving as separate lines. Both quotes need the same household demand, import prices, export credits, period and assumed changes in use. The payback estimates how long later savings take to cover the cost. It does not make that money available on the day you pay.

Should a future electric vehicle be included in a solar quote?

Only as a stated assumption. A future EV should not be treated as a current daytime load, especially if the car will be away during solar hours.

What should the installation scope include?

Check whether the quote includes access, mounting, switchboard work, monitoring, commissioning, removal of old equipment and any identified approvals. Ask what would lead to a variation, and get the answer in writing.

What if one solar quote is much cheaper?

A lower price may reflect a different system or a missing item. Put the proposals side by side and ask each supplier to explain the differences before you compare prices.

When is a home energy assessment useful before buying solar?

When you want a clear order for the work before you choose. That helps when several household changes are planned, or when the quotes rest on different assumptions about how the home uses electricity.

If you want a clear order for the work before you choose a solar quote, start with a home energy assessment.