Ten Common Solar Mistakes and How to Avoid Them

Solar is a mature industry, but that has not stopped homeowners from making expensive mistakes. The ten pitfalls below account for the vast majority of the complaints I hear, and every single one is avoidable with a bit of preparation.

The first mistake is signing with the first installer who knocks on the door. Door-to-door sales campaigns are almost always driven by generous commissions that come out of your quote. Always get at least three written proposals and compare them line by line. Never sign anything in the same visit. A legitimate offer will still be on the table a week later.

The second mistake is oversizing. A system that produces more than you can use, exported at low feed-in rates, has a much longer payback than a right-sized system. Do the math from your actual bills, not from a hypothetical future where you buy an electric car and heat pump the same year. If you are genuinely planning both, size for the plan. If you are only imagining it, size for the reality.

The third mistake is undersizing to save money up front. If your roof has room, adding those last few panels costs almost nothing per watt because the labour and inverter are already there. A slight overbuild in the eighty to ninety percent offset range is often the sweet spot.

The fourth mistake is ignoring the condition of the roof. If your tiles have five years of life left, install solar now and you will pay to remove and reinstall it in a few years. Replace the roof first if it is close to the end of its life. Some installers offer bundled roof plus solar packages that make this easier to finance.

The fifth mistake is choosing a no-name brand for a small saving. The solar industry has seen dozens of manufacturers go bankrupt. Buying from a tier-one brand with a strong balance sheet is worth a modest premium because your warranty is only as good as the company standing behind it.

The sixth mistake is skipping optimisers on a shaded roof. Even a single chimney casting an hour of morning shadow across a string can cut annual output by ten to fifteen percent. Optimisers or microinverters fix this cleanly. A serious installer will do a shading study before the design is finalised and will offer optimisers on strings that clearly need them.

The seventh mistake is buying a battery before you need one. Batteries are still the least attractive part of the payback equation for most homes. Start with a hybrid inverter and add the battery in a year or two once you understand your consumption pattern.

The eighth mistake is not reading the monitoring app for the first six months. This is when installation defects show up. If you never look, you cannot catch them within the workmanship warranty. Set a weekly calendar reminder for the first three months and a monthly one after that.

The ninth mistake is trusting a payback calculation that assumes electricity prices rise five percent forever. Model at least one pessimistic scenario before you sign. If the deal still works with two percent inflation and no feed-in tariff by year ten, you have a robust investment. If it only works with optimistic assumptions, you are taking a policy risk that could go against you.

The tenth mistake is forgetting insurance. Tell your home insurer about the system in writing. Most policies cover it automatically but you want that confirmation on paper before a hailstorm proves you wrong. Some insurers require photos of the installation and a copy of the invoice, and one or two need a small premium adjustment.

There are three honourable mentions that did not make the top ten but come up regularly. Not asking about workmanship warranty duration is one. Twelve months is common. Two to five years is much better and is a sign of a confident installer. Not checking the export limit set by your utility is another. And not reading the fine print on system removal costs if you sell the house is the third.

One final overall principle. Any conversation that pressures you to sign today is a conversation you should walk away from. Solar is a twenty five year commitment. Taking two weeks to compare quotes carefully costs you almost nothing in delayed production and saves you a lot of money and stress over the life of the system. Trust that time to think is your most powerful negotiating tool.