Advice on finding comps /SQFT DIFFERENCE??

[Anthony Geren]

So when your looking at comps in the subdivision, how far apart can the square footage be to affect your comps on the house you wanna buy? 

For example I have comps ranging from 150K to 220K but they vary from 2000SQFT to 2700SQFT. The comps I'm looking at have the same number of beds, bath and 2 car garages ( couple are 3 beds with a couple hundred sqft on the house im looking at).

Any tips and advice on this would help, also if you have any more tips i could use in the future i would greatly appreciate it.