Russell Andrews
Most solar installations go smoothly, but the mistakes that do happen are usually avoidable - and usually come from skipping a step early on, not from anything going wrong during installation itself. Here are the five worth knowing about before you get quotes.
By Russell Andrews
1. Sizing the system to last year's bill, not your actual usage
The most common mistake is basing system size purely on a recent bill rather than genuine future usage. If you're planning an EV, a heat pump, or simply expect your household to grow, a system sized only for today's consumption will leave you buying more grid electricity than necessary within a few years.
Review at least 12 months of bills, not just one, to account for seasonal variation.
Tell your installer about any planned changes - an EV, an extension, more people living at home.
A proper survey should ask about this directly, not just look at your current meter reading.
2. Choosing on price alone, ignoring efficiency and warranty
Cheaper panels aren't automatically bad, but panel efficiency and warranty terms both affect what you actually get for your money over 25 years, not just on day one. Higher-efficiency panels generate more from the same roof area - relevant if your roof space is limited - and a genuinely robust product warranty matters more than the sticker price once you're a decade in.
| What to compare | Why it matters |
| Efficiency rating | Higher efficiency = more output from the same roof area |
| Product warranty | Covers manufacturing defects - check the actual term, not just headline marketing |
| Performance warranty | Guarantees a minimum output percentage over time, typically 25 years |
3. Not checking MCS certification before you commit
MCS (Microgeneration Certification Scheme) certification isn't optional paperwork - it's what makes your installation eligible for the Smart Export Guarantee, and it's the industry-recognised standard installers are assessed against. An installer who isn't MCS-certified, or who can't clearly explain their certification, is a genuine red flag worth walking away from, not a minor detail to overlook. See our MCS certification standards page for what this actually covers.
4. Accepting one quote without comparing
Getting multiple quotes isn't just about finding the lowest price - it's the easiest way to spot when one installer's proposed system size, equipment or scope genuinely differs from another's for no good reason. A single quote gives you nothing to sanity-check it against.
Ask each installer for an itemised breakdown, not just a total.
Compare equipment brands and warranty terms, not just the bottom line.
Ask for references or reviews you can actually verify, not just quoted testimonials.
5. Assuming panels need zero attention after installation
Solar panels genuinely need very little maintenance, but “very little” isn’t “none.” Skipping occasional checks means a developing fault - a failing inverter, a loose connection, a shaded panel dragging down a whole string - can go unnoticed for months, quietly costing you generation the whole time. Basic monitoring (most systems include an app) and an occasional professional check catch this early. See our maintenance and aftercare page for what ongoing care actually involves.
The common thread
Every mistake above comes down to the same thing: treating the initial survey and quote stage as a formality rather than the part of the process that actually determines whether you get the right system. Request a free quote and we'll walk through sizing, equipment and certification properly before you commit to anything.