The house we're currently renovating has a conservatory on the back of it, most probably installed during the 90s(?) - pre-renovation photos attached. Unlike the rest of the property, it's not a thing of beauty but it's probably going to stay for the time being, both for budgetary reasons and because I don't think a suitable replacement would look that much different (see roof comment further below). It's fully double glazed (uPVC), including the roof. The seals on 6 or so of the panes have gone and contain condensation and need to be replaced.
Our dilemma is largely down to the issue of heating and thermal efficiency. We've ended up taking off the French doors which separate the conservatory from an open-plan kitchen / living area and had intended to instead fit bi-folding doors to create even more open-plan space. However, our glazer has suggested that by updating all of the conservatory glass to modern A-rate glass (note, leaving the uPVC frame in-tact), as per the rest of the house, would be sufficient enough to create a usable space in winter, and not make the rest of the adjoining rooms cold. It would also create the most space between the rooms.
Both myself and a couple of people I've since spoken to are very skeptical of this, and whilst it's actually a cheaper option than the bi-folds, I suspect the glazer will actually make more profit from replacing the glass than supplying the bi-folds through a third party. I can't imagine glass has improved THAT much, and the uPVC frame (which is probably the biggest weak spot) would remain the same. I live in the moors of Yorkshire where summer highs are typically around 18-20 degrees, and between 0 and 10 degrees in winter. On this occasion, replacing the glass roof with a solid one is not an option as it would completely starve the adjoining kitchen of light, and opting for something more pitched wouldn't work in the dimensions.
With all this is mind, do you think we could create a comfortable and efficient (heating-wise) living area by replacing all of the conservatory glass alone, or would we be better to replace the broken seal glass and fit the bi-folds to keep out the predominantly chilly weather?