The microwave will sit on the shelf and work fine without the trim kit.

Open the "specifications" tab to find the dimensions you need. It requires 18" depth with plug according to the specs, but you can raise or lower the receptacle if you need to.

No, you cannot enclose a MW into a box without some way for it to breathe. That is what a trim kit does. It gives the microwave a way to breathe. Now, it can sit on a shelf just fine if you leave enough air space all the way around it. Most ususally need 2"-3" of clearance.

Yes, you need either the trim kit or the specified area around the microwave (it will be in the specs for the appliance - but is usually 2 or 3 inches).

Thanks for the advice. Are there any microwaves that are OK with 1" of space as opposed to 2-3". Can I use a hanging kit instead to give it some breathing room but use less space than the trim kit?

- Lalitha

We had ours built in without trim kit and had cabinet maker trim it in with wood. Looks and works great!

If the MW doesn't have adequate air circulation, the risk is a fire. It's a pretty big risk.

The other option is to use an over the range microwave and mount it under the cabinet but not over the range. There is a picture out there of a frigidare one mounted like this and it looks very nice. We almost did this but decided on a speed oven instead.

I have an inch over and under, without trim kit. There's also 3" in the back for the plug and yet more circulation.

Mine sits on a shelf and I'm just fine with it. I can get under it to dust, which happens a lot given all my projects.

I don't have a trim kit on mine. Like you, I personally hate the look of the bulky trim kit surrounding the micro. I had my builder make a cabinet face for the area of the oven and the microwave that works just great instead. I suggest you should do something like this if you want a more 'finished' look.

Installing it with so little clearance and no trim kit is clearly against manufacturer's specs. It's also a BIG FIRE RISK as well as risking the MW ceasing functioning prematurely. If you have enough money that you don't need homeowner's insurance to repay to build your burnt down house, then by all means build in a MW without a trim kit. Doing so is taking a really stupid risk for form over function for most. A $150 trim kit that you can paint to match your cabinetry satisfies the manufacturer's installation requirements. Versus something "pretty" that puts your new 30K kitchen and 300K home at risk for a visit from your fire department. Go ahead and build in a toaster oven and remove the insulation from your wall oven while you are at it or create an elaborate wood hood with no metal liner. The risk would be the same.

We bought an over-the range microwave but did NOT hang it over the range. It is flush (well it sticks out only the width of the door, an inch maybe) with the cabinet front. We also recessed it back into the wall, and our contractor installed an outlet behind it.

The important part is to follow the specifications for clearance around the MW with or without the trim kit. Like any appliance it will overheat if not vented properly. Humidity will also be a problem inside the cabinet.

The trim kit is just that -- a trim kit. It attaches to the outside of the cabinet to cover the opening in the cabinet and does not attach to the microwave at all. I have one and it has vents but the opening might even vent better without the trim. The microwave works just fine without trim. If your cabinet is finished inside you wouldn't need the trim kit at all.