Workers can claim between £1.20 a week – £62 a year - and £2.40 a week totalling £124.80 a year, if they have been working from home, to help pay for costs such as electricity and heating.
Analysis from the charity suggests around 1.16 million people have been working from home during the pandemic and would qualify for the relief. The current tax year ends on April 5.
The energy price cap is set to rise today, with increases of £96 for default tariff customers, and by £87 for pre-payment meter customers.
CAS fair markets spokesperson Kate Morrison said: “Over one million people in Scotland who have been working from home during the pandemic could be entitled to this tax relief, so we’re encouraging everyone to apply.
"Lots of us have been working from home during the pandemic and will have had the heating on for much longer stretches as a result.
“Any money saved on bills will be especially welcome, having come through a cold winter which pushed up heating demands, on top of today’s energy price cap rise, which will result in price hikes for many households.”
Ms Morrison added: “This relief isn’t perfect – we’d like to see it reviewed and increased for people on lower incomes who are more likely to be living in fuel poverty in the first place. If home working becomes more widespread after the pandemic, then this relief could become more important to lots of people over time.”