Commercial Solar for Small Businesses in Southern Thailand
For shops, restaurants, clinics, dormitories, cold storage, warehouses, petrol stations and small factories. Businesses that use power in the daytime use what the panels generate straight away and pay back in around 4–7 years, based on southern tariffs and sunshine. We size every system from the business's real bill and opening hours.
Work on commercial buildings and rooftops by our own team.
Solar for small businesses
Daytime businesses get the most out of solar
Solar panels generate from roughly 8 a.m. to 5 p.m. — the same hours most shops, offices and businesses run their air-con, fridges and machines. The power is used the moment it is generated, and every unit is worth the full tariff of about THB 4.2 per kWh.
What decides the result for each business is when it uses power, the meter type and how much roof gets real sun. So the right system size comes mainly from that business's daytime load.
How the load pattern shapes the design
| Load pattern | Approach |
|---|---|
| Open mainly in the daytimeOffices, clinics, cafés, shops, warehouses | Almost every unit generated is used on the spot |
| Loads that run all dayCold rooms, ice plants, display fridges, water pumps | Uses the power generated in every sunny hour |
| Closed on weekendsOffices and buildings closed Saturday–Sunday | Sized from the working-day load |
| Heavy use from evening into the nightEvening-only restaurants, dormitories | Sized from the real daytime load, or with a battery considered |
Daytime businesses pay back in around 4–7 years. Estimated at THB 4.20 per kWh and Southern Thailand sunshine (1,350 kWh per kWp per year, rainy season included). Actual payback depends on your bill and when you use electricity — we calculate it for your property before quoting.
Choose your type of business
Commercial solar by type of business
Every business has its own loads and site conditions. Choose your type of business to see its design points, system sizes and common questions.
- Shops, restaurants, cafés and shophousesShops that trade in the daytime use power exactly when panels generate. Fridges, air-con and coffee machines run with the sun.
- Offices, clinics and company buildingsOpen in the daytime, so air-con, computers and medicine fridges use almost all the power generated.
- Dormitories, apartments and homestaysDesigned around the power the owner pays for in the daytime, such as water pumps and common-area air-con.
- Cold storage, ice plants and fish piersCompressors that run around the clock use almost every unit the panels generate in the daytime.
- Warehouses, logistics and garagesDaytime operations under wide roofs. Older roofs get a purlin and structure check before every job.
- Petrol stations and forecourt shopsConvenience stores, coffee corners and car washes draw heavy daytime loads. Electrical equipment stays outside the hazardous zones around the pumps.
- Small factories and productionMachines run through the day. Designed from the real load, with PEA and ERC paperwork handled.
- Hotels and resortsAir-con, water pumps and kitchens run all day. Work is done in phases without disturbing guests.
- Rental pool villasPool filter pumps run every day, and several air-con units work hardest in the afternoon.
We serve 13 provinces in Southern Thailand. Site surveys are by appointment, and any travel charge is confirmed before booking. See all service areas
System sizing
Sizing the system from your business's electricity bill
Read your past electricity bills
We look at monthly units used, the meter type and the meter size. This step is free.
Separate the daytime load from the total
We ask about opening hours, days off and your main equipment — air-con, fridges, compressors, pumps — to see how much power is used while the sun is up.
Check the meter type and phase
The PEA (Provincial Electricity Authority) rooftop buy-back scheme only accepts residential meters, so businesses on a commercial meter get a system designed for self-use. On a single-phase PEA meter, about 10 kW is the practical ceiling.
Measure the roof space that really works
Shade from neighboring buildings, rooftop equipment, the waterproofing and the roof purlins decide how many panels fit.
A quote with the assumptions shown
System size, panel and inverter brand and model, when the power has to be off, and return figures with the assumptions laid out for you to check.
Want rough figures before talking to us? The cost calculator covers systems from 5 to 100 kW, and the solar price guide explains what drives the cost (pricing data last checked October 1, 2026).
System sizes
Common sizes for small businesses
The real cost depends on the roof type, structure and cable runs. We quote after the site survey and can design other sizes to suit your roof and usage.
5 kW
single-phase or three-phase · 8 panels
Homes with a bill of roughly THB 3,000–5,000 a month
- Output per year
- ~6,750 kWh
- Roof area
- ~23 m²
10 kW
single-phase or three-phase · 16 panels
Large homes, pool villas, shops and daytime businesses
- Output per year
- ~13,500 kWh
- Roof area
- ~45 m²
15 kW
three-phase · 24 panels
Small factories, hotels and commercial buildings
- Output per year
- ~20,250 kWh
- Roof area
- ~68 m²
20 kW
three-phase · 32 panels
Factories, cold storage and buildings with heavy all-day loads
- Output per year
- ~27,000 kWh
- Roof area
- ~90 m²
Output estimated from Southern Thailand sunshine at 1,350 kWh per kWp per year, rainy season included. Real output depends on orientation, tilt and shade from neighboring buildings.
Tax and accounting
Tax invoices and tax benefits for your business
Tax invoices and withholding tax
- 19Energy is a VAT-registered company and issues full tax invoices in your company's or shop's name.
- 3% withholding tax works as normal for corporate clients.
- The system is an asset that can be depreciated under normal accounting rules; ask your accountant for the exact tax effect for your business.
1.5x deduction on equipment cost
Under Royal Decree No. 805 of 2026, which runs until the end of 2028, companies and people with business income can deduct 1.5 times the equipment cost as an expense. Only the equipment counts — installation labor is not included — and these conditions apply:
- The equipment must be new and never used before
- The equipment must carry the No. 5 energy-efficiency label as specified by the authorities
- It cannot be claimed on top of other investment-promotion measures
Confirm with your accountant how this applies to your business before deciding. Read the full 2026 solar tax deduction rules
Permits and paperwork
We handle the paperwork with the PEA
- Grid-connection application to the PEA (Provincial Electricity Authority)
- License-exemption filing with the ERC (Energy Regulatory Commission) for systems under 1,000 kVA
- An engineer's certification that the roof or deck can carry the load
- A building-modification permit if the installed area or weight exceeds the thresholds in the ministerial regulation
Connecting the main switchboard and changing the meter need a short power cut. We book these ahead on a day off or outside opening hours so your business is disrupted as little as possible. PEA permit service
Equipment we install
- Solar panels
- JA Solar, LONGi or Jinko Solar · N-type TOPCon, dual-glass, 620–630 W per panel
- Inverters
- HUAWEI, Solis or Deye · On-grid and hybrid inverters with a monitoring app so you can check your generation history yourself
- Batteries (hybrid systems)
- LVTopsun or Sunwoda · LiFePO4 lithium batteries for hybrid systems, sized to your night-time consumption
The exact brand and model are written into your quote before you sign anything.
Hybrid systems and batteriesWarranty by component
- Solar panels — product warrantySet by each panel manufacturer for the brand and model you choose, stated in your quotePer manufacturer
- Solar panels — power output warrantySet by each panel manufacturer for the brand and model you choose, stated in your quotePer manufacturer
- InverterMost major brands give 10 years, and it can be extended10 years
- Installation and mounting work by 19Energy19Energy's own technicians handle every job2 years
Manufacturer warranties follow the documents for the exact model installed. See warranty terms by brand
2 years of free aftercare
- Panel cleaning once a year
- Annual system health check
- A check of your building's wiring while we are there
We contact you 14days ahead of each visit and can book a day that doesn't clash with your opening hours. Panel cleaning service
Bill review first, then the site survey
- A first estimate from your electricity bill is free — just send a photo of the bill on LINE.
- The on-site survey costs THB 1,200–1,500 for sites within 100 km, and it is refunded in full against your quote when you go ahead with the installation. It covers fuel, a technician's full day away from installation work, and the time to measure, calculate and write up your report.
- Site surveys are by appointment, and any travel charge is confirmed before booking.
FAQ
Questions from small business owners
Which small businesses get the most out of solar?
Businesses that use most of their power in the daytime — shops, cafés, offices, clinics, cold storage, warehouses and small factories — because every unit generated is used straight away at the full tariff. These businesses pay back in around 4–7 years. Businesses that use most of their power at night are closer to the 6–10 years typical of homes. We check your bill and opening hours before proposing a size.
What information do you need to size a system?
Your past electricity bills, opening hours and days off, your main electrical equipment and the building location. A first estimate from your electricity bill is free — just send a photo of the bill on LINE. The on-site survey costs THB 1,200–1,500 and is refunded in full against your quote when you go ahead with the installation. Site surveys are by appointment, and any travel charge is confirmed before booking.
Can you issue a full tax invoice in our business name?
Yes. 19Energy is VAT-registered and issues full tax invoices in your company's or shop's name, and 3% withholding tax works as normal for corporate clients.
What tax benefits does a business get from installing solar?
Under Royal Decree No. 805 of 2026, companies and people with business income can deduct 1.5 times the equipment cost as an expense, excluding installation labor. The equipment must be new, carry the No. 5 energy-efficiency label, and the deduction cannot be combined with other investment-promotion measures. The measure runs until the end of 2028. Confirm with your accountant how it applies to your business.
Can a shop or company sell surplus power back to the grid?
It depends on the meter type. The PEA rooftop buy-back scheme only accepts residential meters. On a commercial meter, the system is designed for self-use with anti-backfeed protection as the PEA requires, so we size it from your daytime consumption.
What permits are needed?
A grid-connection application to the PEA. Systems under 1,000 kVA file for a license exemption with the ERC (Energy Regulatory Commission), and an engineer must certify that the roof or deck can carry the load. If the installed area or weight exceeds the thresholds in the ministerial regulation, a building-modification permit is also needed. We handle all of this for you.
Do we need to close while the system is installed?
No. Roof and deck work goes on while you stay open. A short power cut is needed only to connect the main switchboard and when the PEA changes the meter, and we schedule these ahead at the least disruptive time, such as a day off or outside opening hours.
We rent our premises. Can we still install solar?
Yes, with the building owner's written consent and a clear agreement on who owns the system, or whether it is removed, when the lease ends. It is also worth checking that the remaining lease is long enough for the system to pay back.
What warranty and aftercare do you provide?
Installation and mounting work carries a 2 years warranty — 19Energy's own technicians handle every job. Panels and inverters are covered by each manufacturer's terms for the brand and model, stated in your quote. You also get 2 years of free aftercare: panel cleaning once a year, annual system health check, a check of your building's wiring while we are there.
Estimated at THB 4.20 per kWh and Southern Thailand sunshine (1,350 kWh per kWp per year, rainy season included). Actual payback depends on your bill and when you use electricity — we calculate it for your property before quoting.
Send us your business's electricity bill
Send your past electricity bills and opening hours. We will propose a system size with the assumptions behind it laid out for you to check.
Our team replies in English — on LINE, by email or by phone. Sending a photo of your electricity bill and your location on LINE is the quickest way to get an estimate.
Factory and commercial projects installed by our own team. See all projects
Read before you decide
- Thailand's 2026 Solar Tax Deduction: Up to THB 200,000 — Who Actually QualifiesThe measure runs until the end of 2028, but several conditions stop people who have already installed from using it. The most common mistakes are system size and the names on the documents.
- Can You Put Solar on a Shophouse or Commercial Building?A small roof but heavy daytime use — a completely different equation from a detached house, and one that often turns out better than people expect.
- Can Solar Really Cut Costs for a Restaurant or Café?Fridges, ice machines and air-conditioning run nonstop while you're open — a pattern where solar pays back well. But your opening hours matter too.