Questions to ask double glazing companies

[TrixieLox]

Hello, we've finally moved into our new house and first thing we want to do is get all the windows replaced with double glazed windows. I've got 3 companies coming to quote over coming week. Any advice / tips / questions to ask?

Don't sign up on the day - it's always possible to bargain them down later on too! I assume they've already been around to measure?

Also, do some research on atest u-values, and therms etc., so you can ask them how theirs compare (have to admit can't remember the research I did - was a while ago, and just to understand the terminology).

Ask them about construction and have them show you samples - again there are some windows that are hinged in such a way that they are easy to break in through.

or "...research on latest..." even

Ask them if they will sign a promise not to phone you up about 38 times after you've told them they were rubbish and you'd never use them again and got them to promise to take them off your database, to ask you if you'd like some more work done.

No, not talking about you Amber Windows at all

Also ask them if they have their own fitters or if they contract out, and if they contract out, how they ensure quality of workmanship.

how will they support the building while windows are out? Will they ACTUALLY support it? (the house was never quite the same after that...)

what about equal sight-line? This is well worth doing.

and yes, never sign up on the day.