We presently have an electric range that has a microwave installed above it, which doesnot have an external venting system (outside). We are remodeling our kitchen with plans in the future to replace our electric range with a gas unit. At this time we would install the necessary gas line and would connect the microwave to an external venting system.
When the time comes to install the gas range what is the minimun distance allowed between the gas stove top and the bottom of the microwave?
We dont want to spend time and money on installation, ie gas line venting system, if they cannot be used in the future due to incorrect spacing between the gas range top and the microwave.
Maximum recommended distance between vent and range is 30". If you want to raise it higher, then you get a bigger fan to compensate for the increased distance.
The real issue is depth. A microwave hood is generally inadequate because it can't draw off steam/odors from the front burners, which are placed beyond its reach. The more powerful your front burners, the more important it is to have sufficient ventilation power straight above them. THIS MEANS the range hood may hit you right in the forehood if you don't plan properly!
I emphasize this because vent hood design differs from model to model. Our previous exhaust fan worked very well, but every time my DH worked at the stove he cussed at it because whenever he bent forward to stir or taste something, he hit his forehead on the edge. It was fine for me, but 2" too low for him. So remember to plan for different heights.
Our new fan doesn't work as well - I can't recommend the lower priced Allure lines of Broan/Nutone, get Best by Broan or Kobe, VAH, FuturoFuturo, etc. - but the design curves upward in front, so at least my DH's forehead has no more bruises, LOL.
Had the same problem when I remodeled last year--opened up the kitchen and had the stove on an island. I didn't want to put a vent over the stove because it wouldn't be very attractive and would be in the way. Decided to go with a range with a vent in the cooktop and vented it out through the floor. Works great. Range is a bit more expensive but not if you factor in the cost of an overhead vent.
Strongly recommend a downdraft vent. Most of the top name manufactures have them and they work great. Really cut down on even the splatter (but you do have to dissemble and wah the parts occasionally - we use the dishwasher whenever needed for that).