I believe you have to find homes that are comparable to the one you plan on buying. It must have the same number of rooms, baths, garage, etc. The tax assessors office will then take a look at 3 homes that are similar to yours. If you have a brick home and the other 3 (West Deerfield township looks at 3 homes, I'm not sure how many Evanston's tax assessor's office will look at) are wood siding, your house will have to pay more taxes based on materials used on your home. Here, you may end up paying more taxes and your insurance will be higher too because to replace brick against wood. It cost a lot more than wood. You will also be assess what the flooring is like. I know when I replace my carpeting with solid oak flooring, my insurance went up when it came to renewal time. Fireplace(s) also adds value to a home, so if you don't have one don't put one in until you get reassessed.

There are ways to lower your taxes. You can claim a homestead exemption, if you're over 65 there's either a tax freeze or it's lowered and you could just find the three (check with assessors office) homes that are very similar to yours and submit to the tax assessor's office. You have to be real careful on this one. I had a neighbor who tried to lower their taxes but because they made improvements on the home before applying for comparables, their taxes went up instead.

Your best bet is to show up in person at your tax assessor's office and ask for guidelines on how to lower your taxes. Get the required papers that you will need to fill out and return to them. Do not make any improvements until your hear back from the assessor's office. (If it was me, I would go and get those papers now even before closing and have your realtor help you locate similar properties like yours with the lowest taxes possible. Submit the papers right after the closing.

Good luck !

I would love to know the answer to this in reverse (much lower purchase price than past sale). Great question!