I have spent the past nine years fitting solar panels on terraced homes, farm sheds, school roofs, small workshops, and the odd awkward shop unit with barely enough loft space to crawl through. Most of my work has been hands-on, which means I have carried rails up scaffold, traced cable runs through dusty voids, and explained inverter faults at kitchen tables after dark. Domestic and commercial solar jobs share the same basic kit, but they feel very different once you are standing on the roof with a survey sheet in your hand.
The survey tells me more than the sales pitch
I trust a careful survey more than any glossy promise about savings. On a house, I want to see the roof covering, rafter condition, chimney shade, loft access, meter position, and where the inverter could sit without annoying the family. A domestic survey can look simple from the pavement, then turn messy once you find old felt, tight rafters, or a consumer unit that needs extra work.
Roof access matters. I once visited a semi-detached house where another company had quoted from satellite images alone, and they missed a rear extension that threw shade across 5 panels in winter. That customer last spring would have ended up disappointed, even though the roof looked fine on a screen. I stood in the garden for ten minutes, watched the shade line, and changed the layout before we priced anything.
Commercial surveys need a colder eye. I look for roof sheets, asbestos risk, steel frame condition, safe access, load limits, fire routes, cable tray paths, and how the building is used between 8 in the morning and 6 at night. A workshop that runs compressors all day can use solar very differently from a storage unit that sits quiet for half the week.
Domestic installs are personal, commercial installs are operational
In a home, the work happens around people’s normal lives. I have fitted systems while toddlers were napping, dogs were barking at the scaffolders, and someone was trying to work from a spare bedroom under the roof we were drilling into. The best domestic installers keep the house tidy, explain the shutdown time clearly, and avoid leaving the customer guessing about what happens on day 2.
One local service page I have seen for Anglesey sets the right expectation that location, roof type, and property use all affect the design. I still tell customers to ask who is actually doing the survey and who will be on site fitting the system. A clear answer gives me more confidence than a neat brochure ever could.
With commercial projects, I spend more time talking about disruption. A small factory cannot always shut down for a full day while we isolate supplies, and a shop may need noisy roof work finished before customers arrive. I once worked on a retail unit where we planned the main cable pull before 9 a.m. because the back corridor had to stay clear once deliveries started.
Panel layout is where good installers earn their money
Shade tells the truth. I have seen installers squeeze 12 panels onto a roof that should have carried 9, just because the drawing looked more impressive. A smaller layout with less shade can beat a crowded one over the year, especially on roofs with dormers, soil pipes, or nearby trees.
On homes, I usually talk through the layout with the customer using plain roof sections rather than technical sketches. A west-facing string might suit a family that uses more power after school and work, while a stronger south-facing section may suit someone at home during the day. There is no single answer that fits every house, and anyone who says otherwise is usually selling too quickly.
Commercial layouts have another layer of compromise. Walkways, roof lights, gutters, parapets, vents, and maintenance access can remove more space than the owner expects. On one warehouse, the first drawing showed around 80 panels, but after we allowed safe routes and avoided fragile roof lights, the sensible number dropped by more than a dozen.
The electrical side should not feel like an afterthought
I pay close attention to the meter area before I get excited about panel count. A neat roof design can still be held up by an awkward incoming supply, crowded distribution board, weak earthing, or a route that needs drilling through stone walls. In domestic installs, this is often the difference between a tidy one-day job and a job that needs extra electrical work first.
Battery storage comes up in nearly every home conversation now. My view is cautious and practical. Some homes suit a battery very well, especially if the family uses power in the evening, but I have also talked people out of buying one when their daytime use already matched the solar generation well enough.
Commercial systems need load profiles before anyone makes bold claims. A business using refrigeration, machinery, lighting, or office equipment during daylight may use a high share of what it generates. A site that only opens at night may still benefit, but the numbers need a sharper look, and export assumptions should never be dressed up as guaranteed income.
Aftercare is where the cheap quote can turn expensive
I have been called to fix systems I did not install, and the pattern is familiar. The panels were fine, the inverter was decent, and the customer had the right paperwork somewhere, but nobody wanted to answer the phone once a fault appeared. A loose connector or monitoring issue can be simple, yet it feels serious when the owner has no idea what the warning light means.
For domestic customers, I like to see handover explained in the kitchen before the installer leaves. The customer should know how to read the app, where the isolators are, what normal inverter noise sounds like, and who to call if generation drops. Ten minutes of patient explanation prevents many worried phone calls later.
For businesses, aftercare needs to be more formal. I prefer a record of panel serial numbers, inverter settings, commissioning documents, access notes, and a maintenance plan that fits the roof type. On a 40-panel home system, a missing document is annoying, but on a larger commercial array it can become a real problem when insurance, landlords, or future contractors ask questions.
How I would choose an installer now
If I were choosing someone for my own house or workshop, I would start with the survey rather than the price. I would ask how they measured shade, how they fixed into the roof, what brand support looks like, and what happens if the monitoring stops working after 18 months. Those answers reveal the installer’s habits fast.
I would also watch how they talk about limits. A good installer can say no to a poor roof face, a weak structure, or a battery that does not suit the way the property uses electricity. I trust that more than a person who says yes to every idea and then hides the awkward parts in small print.
The best domestic and commercial solar panel installers I know are steady, practical people who notice small details before they become expensive. They do not rush the roof survey, they respect the property, and they explain the system in a way the owner can remember next week. Solar is a long-term installation, so I would rather have a slightly slower installer who thinks clearly than a fast one who leaves questions behind.