No. It does not matter. If your question is a technical one.

Aesthetics? it's a personal taste question.

dcarch

Tricia--for best capture of HOGS (heat, oil, gas, smoke), installing a hood 3" wider on each side and 3" deeper than your range/cooktop is recommended. So for you, a 36" wide and 27" (assuming 24" deep range) deep hood is best. Many people get by with a hood the same width as their range, but bigger is better with kitchen ventilation. Good luck!

If the hood is between cabinets, is it practical to have the hood 3" wider on each side?

Is it true that most range hood are about 20 inch deep and the range is about 27 inches deep?

dcarch

Where the cabinets' sides help direct effluent into the hood in the same manner as the wall in the back, the hood can be cabinet width. However, because upper cabinets are rarely deeper than 15 inches, there will be side leakage towards the front of the range. Cabinet sides will need to be cleaned more often if used to reflect effluent upward.

Front extension should be at least three inches beyond the edge of the largest pan that will be used on the front burners. (More technical approaches to hood size may be found in my various comments on this forum, or in the references in My Clippings.) Enough overlap depends on hood height, among other factors.

kas

36" would be better. I have a 30" under cabinet vent over a 30" stove and it just doesn't get the job done

Ok, so goal would be to get hood wider than stove. Thanks!