i've got an equation like:

=IF(B63="A lot of electicial equipment",10*B8*B9,IF(B63="Some electicial
equipment",6.66*B8*B9,IF(B63="A little bit of electicial
equipment",3.33*B8*B9,IF(B63="No electicial equipment",0))))

i'd like to add another layer of complexity, but not sure how, with a
question like

how would you describe your efforts to reduce energy consumption
good
average
bad

where "good" mulitplies the previous answer by the coefficient of 0.6,
"average" x 0.8 and "bad" x 1

i've tried adding things like

=IF(B62="A lot of heating"&B65="Bad",25*B8*B9,IF(B62="A lot of
heating"&B65="Average",0.8*25*B8*B9,IF(B62="Some heating",15*B8*B9,IF(B62="A
little bit of heating",5*B8*B9,IF(B62="No heating",0))))))

thanks

shane