I used to have doors over 50" (shaker style, mdf panel) and they were fine for the 5 years I lived with them, no sign of warping at all.

My current upoer cabinets are 47.5" tall. I've had them over 12 years and they show no signs of warping, but they look massive to me. In my upcoming remodel, I will have stacked uppers, with a 15" on top of 32".

You do have to watch your face when you open them though...

I had approx. 60" high custom doors built in 2003 that haven't warped; they're about 18" wide. Cabinetmaker warned about the possibility of warping but it hasn't happened yet. They're painted maple with furniture grade ply panels.

HTH

My uppers are 45". It allowed me to have crown molding that seemed more proportionate for the size of my kitchen.

Mine are stacked uppers with the glass fronts for the topmost cabinets , so not much help here.
Fori - I am curious, could you elaborate on why you mention that you need to watch your face for a longer upper as against a slightly shorter upper? Would it not be the width (wider Vs narrower) which makes a difference when opening an upper cabinet door?

I suspect Fori, like me, thought "wide" not "tall" when she first read the post. That's where my mind's eye went. Whap!

Whether or not large doors will warp is due to both the construction of the material, and the environmental conditions in which it resides. Wood absorbs and releases moisture over the change of seasons. That causes it to shrink and swell, and possibly warp as well. The amount of movement that the humidity fluctuations cause is more accross the grain than long grain. And it will be in direct relationship to how well you control the humidity in your home. Modern HVAC systems with inline humidifiers do a very good job of keeping the home around the 30% RH that is required to maintain the warranty. Where it gets trickier is the summer months when it's not really warm enough for AC, but the humidity is high and you really need dehumidification more than actual air conditioning. That's why a multi speed unit with zoning can really help during those marginal use months.

Fori & Crcollins1 - I read it the same way at first - you're not alone!

Sophie - what? Abick2 is asking whether they will warp, not what kind of HVAC, etc. s/he should be installing.

Yeah high not wide. oops. For the record, I'm accustomed to pulling back to open a cabinet so I don't get whapped. I don't mind at all. Worth it. :)

But on topic, I've also had really tall doors. They haven't warped. Climate is probably relevant, as well as door material and construction. I'd expect paneled doors to be totally fine but solid slabs might be a concern.

Or not. I apparently am getting a 52" tall slab door for a pantry and my cabinet maker isn't concerned like he is about wide slabs. That goes with what Sophie said--it's the width, not the height, that gets the most change (assuming vertical grain. And we all know how my directional assumptions are working out here...)

I've got 45" doors that are 15" wide. No issues for the last 7 years. Still as when they were new. They are raised panel in stained maple. I'm in TX - humid climate, but always have AC or heat running. Very few weeks out of the year when we don't need it.

I have closet doors that are built exactly like my cabinet doors and they are 5+ feet high, but not unusally wide. No warping in 7 years, but also not v. humid here.