it smells even more in flowering and curing periods!

yea you will need a carbon filter, there are links on this site that show you how to build your own - or they start at about £25 on ebay, but you will need an inline fan - £40.

second hand off ebay will be even cheaper.

but worth investing in - or it will be smelt.

or you could look into an ozone generator to negate the smell - but i would go with the fan and filter as this will help with light temps in grow room too.

do not underestimate the odour - esp. if you live with or around people who do not smoke.

is it your yard or your parents? think about this first if i were you - make sure you are fully aware of any consequences.