Oversize Width for F-9A or F-9AX
JUCA uses a starting point for the size of its F-9A and F-9AX built-in fireplaces as the most popular size in the United States, the so-called 36 by 28. This means that the overall dimensions of the (brass) door facing assembly are about 36" wide by 28" high. (The actual firebox is usually about 32" wide and the opening is usually about 24" tall.)
Since JUCA custom builds each and every fireplace to order, there is no reason you are required to stay with those dimensions. And since JUCA uses manufacturing techniques which allow a lot of flexibility, the company generally doesn't charge to slightly adjust those dimensions for the needs of a particular application.
If you want it substantially larger (wider), then extra material is necessary, so there is a differential in cost. Actually, two differentials! JUCA itself charges an extra $250 for each extra 6 inches in width. And then (often), the larger door set used may have a slight differential.
Thus, for a huge 30 foot long, 15 foot high wall, where a standard sized (36x28) fireplace would look tiny, maybe a 54" wide JUCA F-9A would be used. The unit cost would be the standard F-9A cost ($1,889) plus three extra six inch increments (or $750) for a total of $2,639). Depending on which door style is chosen, another addition may be required there, keeping in mind that many "stock" door styles are not available that wide.
If you DO consider an oversize unit, you need to read THIS LINK on available chimney options which includes comments on the possibility that a larger size chimney may be needed for larger door areas.
The JUCA Home Page is at: http://mb-soft.com/juca/index.html
E-mail to: JUCA1@mb-soft.com