Having an opening that is larger than 28” inches wide by 22” inches tall is not a problem. You can use a local handyman or carpenter to frame or trim in around the size of your opening to make it look like a built-in.
The viewable area has flames that look very close to the real thing, and will look beautiful when properly installed. It maybe a little bit of extra work to build the custom framing out of something like wood, but the end result is a fireplace that will look truly remarkable in your home and offer many years of trouble free, and almost maintenance free enjoyment without the risk and danger of a real fireplace which is far more costly to install and maintain.
