Last updated: October 22, 2026
A solar system hides its mistakes well. Crooked panels are easy to spot. A loose connector, an unsealed roof hole or an undersized cable is not, and you may not find it until the first leak or the first fault code.
Most checks below take a phone call or a few minutes online. They apply to homeowners in the Gulf, the US and the UK, with local notes where the rules differ. A low price doesn't prove bad work and a high price doesn't prove good work. These signs tell you where to dig deeper.
The 12 warning signs at a glance
| Stage | Red flag | Quick test |
|---|---|---|
| Before signing | 1. Can't prove license or approval | Verify with the issuing body yourself |
| Before signing | 2. Won't name brands and models | Ask for model numbers in writing |
| Before signing | 3. No roof or site visit | Insist on a visit before the final quote |
| Before signing | 4. Price far below other quotes | Compare price per kW with identical equipment |
| Before signing | 5. Pressure and large upfront payment | Ask for milestone payments |
| Before signing | 6. Vague warranty | Get workmanship years in writing |
| Before signing | 7. Won't say who does the work | Ask if the crew are employees or subcontractors |
| During install | 8. Equipment doesn't match the quote | Photograph labels on delivery |
| During install | 9. Messy wiring and roof work | Look for loose cables and unsealed holes |
| During install | 10. Ignores heat and dust | Ask for the temperature coefficient and a cleaning plan |
| After install | 11. Missing paperwork | Collect permits, test records and serial numbers |
| After install | 12. Low output and silence | Compare monitoring data with the written estimate |
Before you sign: seven red flags in the quote and sales process
1. They can't prove they're allowed to do the work
Ask for the license or approval number and check it with the issuing body. A verbal "yes, we're approved" doesn't count.
| Region | What to check | Where to check |
|---|---|---|
| Dubai, UAE | The company must be enrolled with DEWA under Shams Dubai. DEWA doesn't accept connection applications from companies that aren't. | DEWA's list of enrolled solar PV contractors and consultants |
| Abu Dhabi and other emirates | Rooftop solar is regulated emirate by emirate. There is no national rooftop solar law. | Your local electricity utility |
| Saudi Arabia, Qatar, Kuwait, Oman, Bahrain | Installer requirements and net metering terms differ by country and change often, so check the current rule rather than trusting a salesperson's summary. | Your electricity utility or national regulator |
| United States | An active state contractor license and proof of liability insurance. NABCEP certification is voluntary, but it signals trained staff. | Your state licensing board; the NABCEP directory |
| United Kingdom | MCS certification isn't a legal requirement, but you need it to qualify for the Smart Export Guarantee. Installers should also belong to a consumer code (RECC or HIES). | The MCS installer database; RECC or HIES |
Equipment gets approved too. In Dubai, DEWA keeps its own list of eligible panels and inverters, and gear that isn't on it can't be connected to the grid. In the UK, some companies still advertise credentials they no longer hold, so check that the certification is current and covers solar PV. In the US, NABCEP is held by individuals, often a company's lead installer, so ask who on your crew actually has it.
2. They won't name the brands and models
A quote that says "Tier 1 panels" and "premium inverter" and nothing else gives you nothing to check. Ask for the make, model number and wattage of every panel, the inverter model, the mounting system and the quantities. SolarQuotes, an Australian review site, treats a refusal to name panel or inverter brands as a warning sign.
With model numbers you can read the datasheet, confirm the warranty terms and, in Dubai, check the model against DEWA's approved list.
3. They skip the site visit
A quote built only from satellite images can't tell you whether your roof is sound, whether a neighbor's building shades it at 4 p.m., or whether your distribution board can take the new system. A visit lets the installer judge panel layout, inverter location and any electrical upgrades. If they won't visit before the final price, expect surprises on installation day.
4. The price is far below every other quote
Cheap can mean inferior components or rushed labor. It can also mean a lean company buying equipment in bulk, so don't stop at the headline number.
Divide each quote's price by the system size in kW, then line up the equipment and inclusions side by side: mounting, cabling, permits, utility fees, monitoring and warranty. Here is an illustration with made-up numbers. Quote A is AED 18,000 for 5 kW and Quote B is AED 27,000 for 6 kW. A costs AED 3,600 per kW (about USD 980) and B costs AED 4,500 per kW (about USD 1,225), a 25% gap. That gap isn't a verdict. It's a reason to ask what B includes that A doesn't.
5. Pressure tactics and a big upfront payment
"Sign today for 60% off" is a sales tactic, not a price. A reputable company will hold a written quote for a reasonable period.
Watch the deposit too. One Australian consumer site warns that paying 50% or the full price before installation puts your money at risk if the company folds. I found no universal "normal" deposit, so ask for staged payments tied to milestones: equipment delivery, installation finished, approval and commissioning.
In the US, check any claim about incentives against the date. The 30% federal residential credit (Section 25D) ended on December 31, 2025. A homeowner who buys a system in 2026 with cash or a loan can't claim it. Leases and power purchase agreements work differently, because the company that owns the system claims a business credit. An installer who promises you the 30% credit on a 2026 purchase is either out of date or misleading you. Incentives change, so verify with the IRS or a tax professional.
6. The warranty is vague
You normally have two layers: manufacturer warranties on the panels and inverter, and the installer's own workmanship warranty. Get the workmanship period in writing and ask who honors it if the company closes. Also ask the question SolarQuotes suggests: is the warranty void if I don't pay for regular servicing? In hot, dusty places, ask whether your cleaning method could affect warranty terms.
7. They won't say who actually does the work
Plenty of good companies use subcontractors. The problem is secrecy. Ask whether the crew are employees or subcontractors and whether a qualified person is on site for the whole installation. A New England installer who writes about shoddy workmanship points to two causes: speed-driven crews and plain incompetence. Both get worse when nobody is clearly accountable.
During installation: three things to watch
8. The equipment on site doesn't match your quote
Check the boxes when they arrive. Photograph the model labels and serial numbers, then compare them with the quote. If something differs, get the change and the reason in writing before it goes on the roof.
9. Messy wiring and roof work
You can't inspect grounding, but you can see wires and roof holes. In the US, the inspection firm IBTS reports wire management failures on 38% of PV projects it has reviewed nationwide. So untidy cabling is common, not rare. Look for:
- Cables hanging loose or resting directly on the roof surface.
- Roof penetrations with no flashing or sealant. Australian inspector GSES says cables passing through a roof need a proper collar flashing, and an unsealed hole invites water into the system.
- Missing labels on the inverter, disconnect switches and distribution board.
- Uneven panel rows and loose conduit.
On a flat concrete roof, ask how the mounts are fixed and how the waterproofing is restored around them.
10. They ignore heat and dust
This is the Gulf-specific test. Panels are rated at a cell temperature of 25°C, and every degree above that costs output according to the panel's temperature coefficient. One manufacturer's technical note says Gulf rooftop cell temperatures routinely reach 65 to 75°C in August.
Here's the calculation with an assumed cell temperature of 65°C, which is 40°C above the rating. A panel at -0.35%/°C loses about 14% (40 × 0.35). A panel at -0.26%/°C loses about 10.4% (40 × 0.26). Same sun, same roof, a gap of 3.6 percentage points that repeats every summer afternoon.
Dust adds to it. The same note cites Qatari research finding that uncleaned panels lose about 0.49% of output per day on average. As rough arithmetic, ten dusty days could cost around 5%. Treat that as an illustration, since dust levels vary by site and season.
So ask for the temperature coefficient from the datasheet. Ask who cleans the panels, how often, at what cost and with what method. Ask where the inverter and any battery will sit, because heat also shortens lithium battery life. An installer who says a Gulf system needs "no maintenance" is cutting corners on the conversation, at least.
After installation: two final checks
11. The paperwork is missing
Before you make the final payment, ask for:
- Permits and utility approval. In Dubai that includes the DEWA No Objection Certificate and a record of the meter connection.
- Inspection or commissioning records showing the system was tested.
- A layout drawing of what was installed.
- Serial numbers and warranty documents for panels and inverter.
- Monitoring app access in your name, not the installer's.
- In the UK, your MCS certificate, which you need to apply for the Smart Export Guarantee.
12. Output looks low and the installer goes quiet
Before you sign, ask what annual output in kWh they expect and what assumptions sit behind it, including temperature and dust losses. In the first month, compare the monitoring data with that estimate. A small gap is normal because weather varies. A large, persistent gap deserves a written complaint, and slow replies at that stage tell you a lot about the company.
Already signed or installed? What to do next
- Keep records. Save the contract, quote, emails, delivery photos, labels and monitoring screenshots.
- Write to the installer. List each problem, attach photos and set a reasonable deadline for a reply.
- Get an independent inspection. Hire a licensed electrician or engineer with no link to the installer.
- Escalate. Contact your utility, licensing board or regulator, or the consumer code the installer belongs to. In Dubai, DEWA lists solar.customercare@dewa.gov.ae for Shams Dubai customers.
If you only do two things, verify the license with the issuing body yourself and get every equipment model number in writing. Those two checks screen out most of the problems above.
Figures in this article are estimates or illustrations unless a source is named. Rules, incentives and net metering terms change and were checked on October 22, 2026. Always get written quotes from licensed installers in your area before you decide.
Frequently asked questions
How do I know if my solar installer is licensed?
Ask for the license or approval number and verify it with the issuing body: DEWA's enrolled contractor list in Dubai, your state licensing board in the US, or the MCS database in the UK. Elsewhere in the Gulf, ask your electricity utility which contractors it accepts.
Is the cheapest solar quote always a sign of bad work?
No. But a price far below the others can mean cheaper components or rushed labor. Compare price per kW with identical equipment and inclusions, and ask the low bidder what is left out.
Should I pay a large deposit upfront?
Avoid it where you can. One Australian consumer guide warns that a 50% or full upfront payment is risky if the company fails. Ask for payments tied to milestones such as delivery, installation and commissioning.
Do hot summers reduce solar panel output, and what should I ask for?
Yes. Output falls as cell temperature rises above 25°C, at a rate set by the panel's temperature coefficient. Ask for that figure, prefer a lower number, and get a written cleaning plan because dust cuts output further.
What documents should I get after installation?
Permits and utility approval, commissioning or test records, a layout drawing, equipment serial numbers, warranty documents and monitoring access in your name. In the UK, also your MCS certificate.
Sources
- Dubizzle: Solar Powered Home in Dubai With DEWA (enrolled contractors only)
- Property Finder: Solar Panels for Homes in UAE (DEWA approval, NOC, approved equipment)
- SurgePV: UAE Solar Regulations by Emirate (no national rooftop law)
- Business Dubai: DEWA Shams Dubai enrolment and equipment approval, 2026
- Solar.com: End of the 25D federal solar tax credit
- EnergySage: Questions to ask when choosing a solar installer (NABCEP, warranties)
- Green Mountain Energy: Finding reputable solar installers (license lookup, reviews)
- MCS: Membership benefits for installers (Smart Export Guarantee route, consumer codes)
- Sunlith Energy: MCS certification explained (not a legal requirement; checking certification)
- Stratford Energy: MCS certificate guide (outdated credentials)
- IBTS: Common deficiencies in solar PV installations (38% wire management figure)
- GSES: Solar installation common mistakes and best practices (roof flashing, cabling)
- SolarQuotes: Warning signs with very cheap solar (brands, subcontracting)
- SolarQuotes: Questions to ask before buying solar (warranty and servicing)
- Why Solar: How to vet a solar installer (pressure tactics, deposits)
- Solar Calculator: Tips for selecting the best solar installer (site visits, cheap systems)
- New England Clean Energy: Shady solar workmanship
- Sinovoltaics: Temperature coefficient of a solar module (calculation method)
- Nastech Solar: Dust, heat and humidity in MEA (manufacturer note; cell temperatures, QEERI dust figure)