Economic and economical are adjectives.
We use economic to mean ‘related to trade, industry or money’:
The economic forecast for next year is not good.
The President spoke mostly about economic policy.
We use economical to mean ‘not using a lot of money’:
Hybrid cars are very economical. (They do not cost a lot of money to run.)
Solar energy for your home is expensive in the short term but it is more economical in the long term.
Source: English Grammar Today