Economical has a narrower meaning than economic. It means ‘not wasteful or extravagant; designed to save money (e.g., through efficiency)’:
He is very economical: he always turns off the light when he leaves the room.
That heating system is very economical: it operates at the lower, off-peak rate.
Economic means “relating to the economy of a country, a household or the income of an individual; relating to the study of economics; financially rewarding; efficient”:
(The economy) Economic growth; economic measures
(Economics) Economic theories; economic analyses
(Income) He retired for economic reasons; economic migrants
(Financially rewarding) It was no longer economic to keep the factory open
(Efficient) The economic use of resources
Incidentally, is the first syllable pronounced EEK or EKK? The answer is either – it is one of those rare cases where there is no preference. The two pronunciations are used more or less randomly, both in UK and US English.
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