Buying windows over a phased renovation

[lookseehear]

Does anyone know what the norm is if you aren't able to order all your windows up front because you don't have finalised measurements? My builder is getting on to me about ordering windows for the extension which is fair enough, but we will also be replacing the windows for the rest of the house over the coming year (somewhere in the region of 25 windows overall) and some of the openings are going to be extended in width and or height from existing. This makes ordering all of them at once a challenge, but I don't want to buy a few then be over a barrel when it comes to ordering the next tranche because we want them to match the existing so can't shop around.

 

One option is to buy the windows for the extension and accept that these may be different to the rest of the house, then try to get ourselves in a position in the spring to bulk order windows for the rest of the house as a whole, but ideally we'd agree some kind of price based on an estimate up front then tweak as necessary, or do suppliers ever offer a price per m2 or similar?

 

Second question is about fitting. I assume for best results the glazing supplier will need to also do the fitting, or can I get my builder to do this? We're looking at triple glazed alu clad timber ideally.

[Mr Punter]

I think you may be best ordering in 2 hits.  The supplier may not want to be held to a price for a future order.  If they turn up before you need them they will get in the way and could be damaged.