I just measured mine, they are 19 1/4 ", outside dimensions. I knew which microwave I was going to get, so we made sure it would fit. The lowers are 25 1/4".

I think it depends on a lot of things....
How big (D) are the appliances you want to put in there ?
How much counter space overall do you have ?
what is next to this area ?
I think 18" would be nice, but that only leaves you 7" in front & if you don't have a lot of other counter space, that may not be good. Also If it's sitting out in the middle of a run of counter top, I'd stick with 12". If it's agianst a wall or tall, deeper cabinet on one side, then 18" would be great. I can't really think of any reason for a 24" garage, unless you have oodles of space, & that would look cool, like one tall cabinet.

Here is a link that might be useful: granite countertops

armomto3boys, what is inside the deep upper cabinets above the garage? do you have regular shelves there or pullouts?

I have regular shelves. Mainly glasses and other glassware will be above the microwave. Coffee mugs and coffee/beverage supplies will be on the other side. The coffee maker and blender will be in that garage.

I have 13" uppers -- they are the standard with Brookhaven and Woodmode. I also have 13" deep cabinets on the back side of my island. All my small electric appliances fit in there -- some sideways -- even the KA 6 qt pro mixer. The mixer is a just barely at 13", so I think some things would be too small with 12". Also would make a difference if you have inset cabinets. Mine are frameless.

I kind of copied mine from photos I found on the internet, without being on *HERE*, and not knowing dimensions. :)

I could see in several pictures I had collected an end cabinet 'stuck out' further than the rest of the run and went all the way down to the counter. So I drew this end cabinet 20" wide by 16" deep and my carpenter made it. I love how it looks but it is pretty deep. It's AMAZING how much stuff I can stuff in there. :D

The rest of my uppers are 12" standard. My appliance garage = One Of A Kind!

Our house is a new build so we had the flexibility of designing the kitchen we wanted. We have a 10.5' run of cabinets that includes the refrigerator. Because we knew we wanted a standard depth refrigerator and appliance garages our counter along this run is 30" deep. This allows our refrigerator to not jut out from the surrounding cabinets and it also allows us extra depth for the appiance garages. Our appliance garages are 18" deep (actually 17" interior with a 1/2" back wall and a 1/2" door in front) while we also have 12" of usable space in front of them. The wall cabinets are Brookhaven standard depth 13" but they are pulled 5" forward from the actual wall. I'm not sure of the construction method but the cabinet installer built out this portion of the wall with blocking in front of the real wall. Hope this picture is useful.

{{!gwi}}

This may not be true anymore but when we were shopping around for cabs, I was told (by more than one source) that the hardware for the flip up door requires an 18" deep cabinet.

I have Brookhaven (like others who posted above) and my garage is 18" deep which is how they make them. The cabinets above are also 18" deep which is nice because I got a little bit of extra storage space there. However, unlike flseadog's appl garage/cabinets which she has pictured above, mine are one piece - cab and garage. So they might make them differently now. (Mine are almost 5 yrs old.)

In case it is helpful, I thought I'd post pics of our appliance garage even though it is not a flip up/down type of door like the OP asked about.

I needed depth for our toaster oven but didn't have the space to make the garage deeper due to the proximity to a window. We are very happy with this recessed solution. There is a BR closet on the other side of the wall - the space between the sheetrock made the difference for us!

The interior is a hair under 17" and we had an outlet installed inside, of course.

View with door closed

Smarge, I was just talking to DH about doing something like that. The cabinet itself isn't recessed, is it? Just the toaster oven?

The upper cabinets are not at all recessed. The interior, of the garage-only, IS recessed. I'll take a picture that will also show you what NOT to do.

1) A worker "forgot" about the recessed cabinet while working in the closet behind it and put a screw through my cabinet material (see orange flag on left side). Just one of thousands of screw ups we've learned to live with (did I mention I hate my contractor at this point? We still have a HUGE punchlist for a project he was supposed to have finished in March 2008.)

2) the countertop fabricator was not shown the recessed cabinet so he assumed the rear dimension and installed the counter with a major piece missing! They didn't even mention it to us; I noticed the first time I opened the garage and freaked out bc the rear 4.24" of my garage had no counter! If this had been done properly there shouldn't be a seam in there (see orange flag on counter). BE THERE WHEN YOUR COUNTERS ARE TEMPLATED! YOUR CONTRACTOR DOESN'T NECESSARILY GIVE A CRAP ABOUT THE DETAILS! (and if he does, kiss his feet!) (Now I'm noticing the not-flush plate cover again - grrrrrr. You'd think they didn't BUILD that wall and install that new electric! MAN!)

(whew - sorry for the rant, but warning you all means reliving it a bit for me -- I think I need a break from GW for a bit.)

Another reason why I'm my own contractor because I do care. I have to live with it! Template done today and granite installer very aware of the appliance garage. It will be installed after granite is in and before backsplash granite is installed. Found out from granite guy my cabinet installer screwed up on the bar....not straight! The last thing he did before he left and he sure as hell knew it too. Good thing I held out a small amount of his pay for surprises.