Compilation of Promotions for Credit Cards - Cash Cards to Install Solar Panels in 2026 with Installments Starting at 2,550 Baht/Month

Electricity bills may rise further! How high they will go is an unknown question. Therefore, ordinary people like us need to look for ways to save energy, such as "installing a Solar Rooftop system."

Thairath Money has gathered promotions from credit cards and cash cards matched to the three popular installation sizes, clearly showing how much of your payment can be deducted from taxes.

Understand first which size suits your home.

If you want to install a Solar Rooftop to save on electricity bills, you need to ask yourself how much electricity your home uses and what your monthly bill is. To simplify, we provide examples of three system sizes to choose from as follows:

- Size S, 3 kW system: starting budget 120,000 baht, suitable for small houses with electricity bills of 3,000-4,000 baht per month.

- Size M, 5 kW system: starting budget 150,000 baht, a popular size for typical detached houses with electricity bills of 4,000-6,000 baht per month.

- Size L, 10 kW system: starting budget 300,000 baht, for large homes with electric vehicles or electricity bills in the tens of thousands.

Although the final installation price depends on each service provider, generally these packages include solar panels and main equipment such as solar panel modules, mounting brackets or bases, grounding wires, junction boxes, power inverters, electricity meters, and safety systems.

Finally, if you want to install a Solar Rooftop at home, you must fully comply with the Revenue Department's conditions, such as having an On-grid system with a maximum installed capacity of no more than 10 kW per house (batteries are allowed according to the Department of Alternative Energy Development and Efficiency). Be sure to check these carefully before purchasing.

Summary of bank promotions: Who offers the highest cashbacks and who provides the longest installment plans?

KTC Credit Card / KTC PROUD Cash Card

• Promotion: 0% installment for up to 10 months, cashback limited to a maximum of 6,700 baht per sales slip, and a maximum cashback of 67,000 baht per card per month. You can also redeem KTC FOREVER points for an additional 13% cashback.
• Minimum loan amount for installment: 70,000 baht (installments of 6 months or more per sales slip).
• Promotion period: Ends 30 Nov 2026 GMT+7.

KBank Credit Card

• Promotion: KBank Smart Pay 0% installment for 6-10 months, cashback limited to a maximum of 20,000 baht throughout the campaign.
• Minimum loan amount for installment: 12,000 baht per sales slip.
• Promotion period: Ends 30 Apr 2026 GMT+7.
• Business credit cards, corporate credit cards of all types, Fleet Cards, and ThaiBev credit cards are not eligible for this promotion.

ttb Credit Card / ttb flash Cash Card

Promotion: Credit card installments at 0% interest for up to 10 months.

• ttb flash Cash Card offers 0% installments for up to 36 months or up to 60 months; installment amounts and conditions depend on the merchant/provider.
• Both cards have a maximum cashback limit of 26,000 baht throughout the campaign (including all participating merchants).
• Minimum loan amount for installment: 50,000 baht per sales slip.
• Promotion period: Ends 30 Apr 2026 GMT+7.

CardX Speedy Cash Cash Card

• Promotion: 0% installment for up to 60 months, applicable only for installations with A SOLAR company.
• Minimum loan amount for installment: 5,000 baht per sales slip.
• Promotion period: Ends 30 Jun 2026 GMT+7.

CardX and SCB (Siam Commercial Bank) Credit Cards

• Promotion: 0% installment for up to 10 months and 10% cashback, applicable only for installations with A SOLAR company.
• Minimum loan amount for installment: 5,000 baht per sales slip.
• Promotion period: Ends 30 Jun 2026 GMT+7.

Krungsri Credit Card

• Promotion: 0% installment for up to 10 months or choose special interest installments at 0.74% per month. Cashback limited to a maximum of 18,000 baht per card throughout the campaign.
• Minimum loan amount for installment: 70,000 baht per sales slip.
• Promotion period: Ends 1 Dec 2026 GMT+7.

Tax deduction measure of 200,000 baht: How much actual cashback does it provide?

One factor stimulating solar sales this year is the personal income tax deduction measure, where the government allows a deduction for actual payments but not exceeding 200,000 baht.

However, even if you have installation expenses of 200,000 baht, this is not the tax refund amount the government will give you. Instead, this amount is "deducted from your income," then the tax reduction is calculated to lower your tax liability.

Example:

• Annual income: 500,000 baht.
• Standard expense deduction: 100,000 baht.
• Personal deduction: 60,000 baht.

Net income = 340,000 baht. According to the Revenue Department's criteria, tax owed is 11,500 baht (combined 5% and 10% tax brackets).

If you install solar panels costing 200,000 baht and deduct this, net income = 140,000 baht. Under this criterion, no tax is owed, so you save 11,500 baht in taxes.

Before exercising the tax deduction right for solar installation, you must know key conditions: installation must be in a residence with a system not exceeding 10 kW, and the proof must be a full e-Tax Invoice (electronic tax invoice).

The name on the invoice must match the electricity meter owner and the person filing the tax return.

*Total annual income from all sources minus standard expenses minus deductions equals net annual income.

Source: Kwealth.

For homes focusing on maximum value, choosing credit cards offering large cashback within the first 10 months helps reduce initial costs immediately. However, if long-term installments are preferred so that electricity bills cover the payments, cash cards with 36-60 month installments are most suitable.

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