Twenty-five thousand rupees is the threshold at which the frost-free convertible double door becomes available, and it changes what you are buying. The Whirlpool IF INV CNV 278 at around ₹24,500 is the cheapest genuine one here — 235 L, an inverter compressor, six convertible modes and no manual defrosting ever again.
Whether to spend the full budget is a real question rather than a rhetorical one. A 5-star single door at ₹17,500 draws 108 units a year against the double door's 201, a difference of about ₹745 annually. Over twelve years that is close to ₹9,000, which is a third of the double door's price. What you get for it is auto-defrost, even cooling and roughly the same usable space in a taller cabinet.
For one or two people, the single door is still the better buy and the saving is real. For three or more, the double door's convertible modes and dry, even cooling justify the running cost — and the Whirlpool's zeolite crisper, which measurably extends how long produce lasts, will claw some of it back in food that does not get thrown away.