15 kW Solar System, Supplied and Installed
Businesses that run all day use almost every unit the moment it is generated, so they pay back noticeably faster than homes.
What the system includes
- 24 JA Solar, LONGi or Jinko Solar panels — N-type TOPCon, dual-glass, 620–630 W per panel
- HUAWEI, Solis or Deye inverter, three-phase
- Mounting structure and fixings suited to your roof
- Control box and protection devices to utility standards
- All permit paperwork with PEA (Provincial Electricity Authority) and the ERC (Energy Regulatory Commission)
- 2-year installation warranty
How much this system can save
Every figure comes with the assumptions behind it, so you can compare it with other quotes.
| Southern Thailand sunshine | 1,350 kWh per kW per year |
|---|---|
| Generation per year | 20,250 kWh |
| Electricity rate used | THB 4.20 per kWh |
| Savings per year — 100% self-use | THB 85,050 |
| Savings per year — 70% self-use | THB 59,535 |
| Per month (70% self-use) | ~THB 4,961 |
“Self-use” means the share of generated power that is used in the building the moment it is produced. The rest flows out to the grid, where the buy-back rate is far lower than the price you pay for electricity. That is why a home that is empty during the day benefits less than one where someone is in, and why we ask to see your bill before quoting.
15 kW system at a glance
- System size
- 15 kW (three-phase)
- Panels
- 24
- Roof area needed
- ~68 m²
- Generation per year
- ~20,250 kWh
- Savings per month
- ~THB 4,961
The price depends on your roof and the actual site. We survey the site and quote a price that holds.
Warranty
Broken down by component
Panels, inverters and installation work carry different warranty periods, listed part by part below.
Per manufacturer
Solar panels — product warranty
Set by each panel manufacturer for the brand and model you choose, stated in your quote
Per manufacturer
Solar panels — power output warranty
Set by each panel manufacturer for the brand and model you choose, stated in your quote
10 years
Inverter
Most major brands give 10 years, and it can be extended
2 years
Installation and mounting work by 19Energy
19Energy's own technicians handle every job
FAQ
Common questions about the 15 kW system
Who is a 15 kW solar system right for?
Businesses that run all day use almost every unit the moment it is generated, so they pay back noticeably faster than homes. As a guide, it suits: small factories, hotels and commercial buildings. A system this size generates about 20,250 kWh a year. If you use much less than that, the surplus flows out to the grid at a low buy-back rate, which slows your payback.
How much can a 15 kW system save on my bill each month?
If you used every unit it generates yourself, you would save about THB 7,088 a month. Most homes don't use all of it during the day, so the figure we typically see is closer to THB 4,961 a month. It still depends on how each household uses power — we calculate it for your property from your real bill before quoting.
How much roof space does it need?
Each panel is roughly 2.8 m². A 15 kW system uses 24 panels, so it needs about 68 m² of sunny roof, with no shade across it during the day. Even partial shade can pull down the output of the whole array.
How much does a 15 kW system cost?
The price depends on the roof type, the condition of the structure, the distance from the panels to the electrical panel, and the location — which can differ a lot even for the same system size. So we survey the site and quote a price that holds.
Compare with other sizes
5 kW
single-phase or three-phase · 8 panels
Homes with a bill of roughly THB 3,000–5,000 a month
See details10 kW
single-phase or three-phase · 16 panels
Large homes, pool villas, shops and daytime businesses
See details15 kW
three-phase · 24 panels
Small factories, hotels and commercial buildings
You are viewing this size
20 kW
three-phase · 32 panels
Factories, cold storage and buildings with heavy all-day loads
See detailsWant the real price for your property?
Send us your electricity bill, then book a site survey. We'll quote a price that holds, with all the calculations included. The bill estimate is free, and the survey fee is refunded in full when you go ahead.
Systems of a similar size we have installed for clients. See all projects
Read before you decide
- Monthly Bill of THB 3,000, 5,000 or 10,000 — What Size Solar System Do You Need?The best-value size is not the largest your roof can hold — it is the size that matches the electricity you use during the day.
- Can You Pay for Solar in Installments? Financing Options Worth KnowingYou can pay in installments. Work out how much of your savings goes to interest, so you know the full cost in advance.
- Thai Electricity Is THB 3.95 per Unit for Sep–Dec 2026 — How to Calculate Solar Payback CorrectlyThe tariff you see in the news and the rate you actually pay are not the same. Here's how to work out your own real cost per unit so your payback calculation is accurate.