The sheltered housing resident in Troon, South Ayrshire, said it was like a firework going off in his living room.
The incident left the device broken apart and caused charring to his wall, carpet and the plug point where it had been charging.
Local trading standards officers have issued a warning to e-cigarettes users to make sure their devices are safe.
South Ayrshire Council said: “In a recent incident at a sheltered housing unit in Troon, a cheap e-cigarette bought on an overseas holiday exploded after being plugged in for the first time and charged for just five minutes.
“The pensioner heard a loud bang and a whoosh, describing the explosion as being like a Roman candle firework going off in his living room.”
E-cigarettes are increasingly used by people trying to cut down on tobacco smoking or quit altogether.
Tips for safe charging include always using the charger provided for the product and not leaving it unattended or letting it overcharge.
Users are advised not to over-tighten the atomiser when connecting it to the charger and check the battery is undamaged and has built-in protection from overcharging or overheating.
Mike Newall, head of neighbourhood services at the local authority, said: “We charge so many gadgets these days that it’s easy to take their safety for granted, but as incidents like these show there is a real and present danger. While in the majority of cases charging will be completely safe, it’s worth remembering that batteries can and do overheat, and without taking proper care to ensure your device is safe you can run the risk of starting a fire.
“We would recommend buying from a trusted source, always use the charger that comes with your device and, above all, use common sense.”
Earlier this year, a man from Rochdale in England suffered burns to his leg when his e-cigarette caught fire in his trouser pocket while he was ice skating with his children.
Mick Bennett needed skin grafts and spent ten days in hospital after the incident, while there have been numerous other reported incidents of the devices catching on fire or exploding.
Official figures estimate that there are 2.2 million e-cigarette users in Great Britain.