[VBprogrammer]

A 2kW electric heater can heat up any reasonable size office room up to a temperature where you are going to have to strip to your underwear (or turn it off) in under an hour in my experience.

Even if it's on 8 hours a day constantly, 5 days a week, 4 weeks a month that's 320kWh or just over £100 a month at UK energy prices.

[dijit]

additional note: UK energy prices are currently the highest in Europe.

not sure if that makes your anecdote out of date or if it puts further shade on the parents comment.