Replacing sash windows but keeping the frame
An Accoya chap visited and saw my old sash windows. He advised that they don't change the box in old Victorian properties if it appears to be in good condition, because there is no need. He tapped on them, tried to put a sharp item through, and said they're fine, I can just get new sashes.
He also said that because the old boxes are narrower for single pane windows, the new ones will be double but without a gap (or krypton) between them.
All the other contractors that quoted, gave me a quote about changing the box as well, as requested.
It can be a messy job changing the box as it's attached to tiles, ceiling and side architrave and changing just the sash is indeed going to be much simpler.
I was thinking of changing the whole lot when I was going to redo my kitchen, but that won't be happening for a while, so it's just the windows for now.
What do you think ? Was he just trying to sell, or is this solid advice? For me, the boxes look crap but they appear to be structurally fine.