**Yes, 0% APR can be a bad idea—but in your circumstances, taking the full 48 months can be financially sensible.** If the price is the same, there are no fees, and the entire term is genuinely interest-free, paying £1,500 gradually lets you earn interest or reduce interest elsewhere.

The main downsides are:

- **The contract may have catches.** Confirm that £1,500 is the *total* remaining amount payable, with no administration fees or final payment. Check what happens after a missed payment, and distinguish a fixed 0% instalment loan from a deferred-interest offer. Your actual credit agreement determines this.
- **Missed payments can cost you.** Even an interest-free loan can carry late fees and damage your credit history. Set up a Direct Debit and keep enough money in the payment account. [MoneyHelper](https://www.moneyhelper.org.uk/en/everyday-money/credit/managing-credit-well)
- **It remains a borrowing commitment.** If you apply for a new mortgage or remortgage with another lender, the repayments can reduce the amount they consider affordable. Several “negligible” monthly payments can add up. [FCA mortgage affordability rules](https://api-handbook.fca.org.uk/files/sourcebook/MCOB.pdf)
- **It can encourage overspending.** The saving disappears if keeping the £1,500 makes you feel able to spend another £1,500. Likewise, a cash-payment discount could outweigh the benefit of financing.
- **Your future salary is uncertain.** Being employed now does not guarantee another 48 pay packets. Your existing savings make this much less concerning, provided you account for these payments when sizing your emergency fund.

Your mortgage idea is reasonable: replacing £1,500 of interest-bearing mortgage debt with £1,500 of interest-free furniture debt should save interest. **Check your mortgage’s overpayment limits and early repayment charges first.** Also, money paid into the mortgage may be difficult to access again; flexible or offset mortgages can offer more access. [MoneyHelper’s overpayment guidance](https://www.moneyhelper.org.uk/en/homes/buying-a-home/should-you-pay-off-your-mortgage-early)

A cautious alternative is to keep the £1,500 in a separate interest-bearing savings account and use it to fund the instalments. That preserves access to the money and avoids relying on future wages. Compare the savings return **after any tax** with your mortgage rate when deciding between saving and overpaying.

Given the savings and emergency fund you describe, I would see little financial reason to pay immediately **if all those conditions hold**. Paying outright still buys simplicity and one fewer obligation, which you may value more than the interest saving.