For exterior doors and transoms above, the transoms look best if they are at least a 1'-6" clear opening, since the transom trim reduces that dimension by 4" or more, depending on trim acutally used.

For 10' interior ceilings I would use a 6'-8" door and at least a 1'-6" (or more) transom.

What is the head height for all of your windows?

I would want to know the finished height of both options and how they might look next to each other.

I don't think 8' is necessary aesthetically, and the downsides are greater cost and increased height increasing the possibility of more warping. I have pretty tall ceilings in most of my house, but pairing normal height doors with transoms works fine for me. See if this appeals to you or not:

Front door:

Dining room:

I have 8' doors internal and external on 10'ft. ceilings first floor and all windows are at the 8' height. Upstairs, with 9' ceilings, I have standard size doors 6'8". But I have no important rooms upstairs (bonus area.)

I suppose climate matters as does material for door.

Triple point locks are mandatory in some areas for 8 foot doors. That can raise the cost. Our last house had 8 foot double doors for 8 years and no warpage issues. But a cheap 8 foot door might have issues.

I would not do sidelites personally for the issue you mention - privacy. In my area, they are out of style.

We did an 8ft door AND a transom. :) No sidelight. All interior doors are 8ft.

Regarding warpage & multipoint locking... I would strongly suggest that main entry doors are fully covered by deep overhangs that prevent direct sun on the entry door. If you do this, wood doors with composite cores, fully sealed on all six sides, single point locks usually perform fine. There are also some great looking fiberglass versions of many doors.

Read your door warranty and make sure you meet requirements.

If you have an exposed door, use something higher end with layers of weather-stripping and multipoint. I'll typically use Anderson or Eagle clad French for these issues & have just installed a few pairs of Milgard French.

We're building homes that shed water, not submarines.

Holly-

Because he has a 100% markup and thought he could get away with it....

Plus he has to install the door. Home Depot only sells the door...:-)

$5200 over retail sounds a little pricey for an install, especially since he can get the door at a lower price with a contractor discount....

Yep...I agree! Need to check that boy's prices and workmanship!

What did he say, then?