Pros and cons of removing weight boxes

[hippo49]

I am trying to advise my elderly mother, who is replacing her timber sliding sash windows with uPVC sliding sash.

It seems that the weight boxes can either be removed (which Everest did at my own house) or left in place with the new frames fitted to the old timber.

Can anyone please advise on the pros and cons of the two methods?

Thanks

 

[hippo49]

Ok. Here are my own thoughts:

Leaving weight boxes:

Pros:

1. Easier/cheaper
2. Less disruption to internal decoration.

Cons:

1. Might have to repair rotten areas of boxes first, esp at the bottoms.
2. Leaves old timber hidden, where it will be relatively or completely unventilated.
3. Could spray old timber with preservative but couldn't repeat spray. Timber preservative can damage uPVC I think.
4. More of frame visible from outside.
4. Reduction in glass area, hence light.

Pros and cons of removing the weight boxes are essentially the opposite of the above.

Any things I have missed?

Which would you do: remove or leave boxes?

Thanks.