10 Criteria for Choosing a Solar Installer in Bangkok (2026)

Choosing a good solar installer is the single most important factor in whether your system is worthwhile and safe long-term. This article compiles 10 criteria to weigh before you decide in 2026.

1. Business licensing & certified engineers

Check that the company is properly registered and has licensed electrical engineers to certify the design and sign off the installation — required for utility approval.

2. Experience & number of completed projects

A company with many real installations understands diverse sites and solves problems better. Ask to see a portfolio and photos of actual work.

3. Panel & inverter brands (Tier 1)

Choose Tier-1 panels and standard inverter brands such as Huawei, SMA or Growatt with service centres in Thailand, for durability and easy warranty claims.

4. Warranty terms

Compare panel (25-year performance), inverter (5-10 year) and workmanship warranties, and read the fine print on exactly what's covered.

5. Permitting & power buy-back handling

A good company handles MEA/PEA and ERC permitting and grid connection for you, rather than leaving you to chase paperwork.

6. Service area & on-site response time

A company near you, or with a team covering your area, surveys and services faster after the sale.

7. Price per kW & quote transparency

Ask for an itemised quote listing every component. Beware unusually cheap prices that may cut equipment or installation quality.

8. After-sales monitoring & maintenance

A good system lets you monitor production via an app and offers annual cleaning and inspection packages.

9. Real customer reviews & ratings

Read reviews on Google and social media — look at both praise and how the company handles problems.

10. Installment options & financing partners

Some companies offer 0% installments or energy loans, letting you start without a large upfront payment.