The cheapest option would be a buff and coat. Wouldnt change color but would refresh the floor. Its where the abrase the top layer of finish and lay down a fresh coat of your choice of poly.

Next would be to sand. Since its eng. you would want a pro. Its real easy to sand thru the top layer of wood. Thus wrecking the floor.

Recoats to engineered flooring can be problematic. Make sure you test for adhesion before investing time and materials. Contrary to popular belief, not all engineered hardwood can be successfully recoated.

Recoats to engineered flooring can be problematic. Make sure you test for adhesion before investing time and materials. Contrary to popular belief, not all engineered hardwood can be successfully recoated.

Any idea what I should expect to pay for a buff and coat. 1500 sf, Chicago.

Probably around $1.00 per sq.

If you put an ad on craigslist you may find some crappy people claiming they can do it for less but thats a risk. Anything above 1.50 and keep trying.