Economic vs Economical

From Mcmillan dictionary, here is some advice about the adjectives economic and economical. People often confuse economic and economical. 

Use economical to describe methods, products, machines etc that are not expensive or do not waste money or other resources:

✗ They want people to buy more economic cars.  
✓ They want people to buy more economical cars.  
✗ Email is an efficient and economic way of contacting a large number of people.  
✓ Email is an efficient and economical way of contacting a large number of people.
 
Use economic to describe things that are related to the economy of a country and how well it is performing:
✗ a long period of economical growth  
✓ a long period of economic growth  
✗ a serious economical crisis  
✓ a serious economic crisis
 
The related adverb for both adjectives is economically:
help for some of the country’s most economically depressed communities.
The average domestic heating system could be run much more economically.