more replacement window questions particularly for Sofiaames

[jasper]

is double glazing really significantly more insulating?

When replacing windows do you need to involve the local planning dept (building warrant)?

my house was built in the 1830s but is not listed. At least I don't think so but how would I know for sure?

As per other thread highly recommended local joiners have recommended replacing old draughty (but gorgeous) sashes with double glazed mahoganny casement windows that look like sashes but are fixed in the bottom half but swing out to open in the top half.
Can these really look like sashes?
Estimator says our house is so exposed that conventional sashes will be too draughty - that si the reason we are considering replacement in the first place.
please advise.
Thanks

Hi. Sooo yes double glazing (especially argon filled which is required nowadays) really is significantly more insulating. You won't need permission to replace windows unless you are in a conservation area or your house is listed (it would either be in the pack when you bought the place or you would have been notified if it had been done while you owned the place - in any case you can check if you are listed/conservation area fairly easily by calling your local planning department and asking).

To replace existing sashes with double glazed sashes you need to replace the frame as well which can get expensive, but I suspect that you would need to replace the frame to put in the casements too. I don't see why double glazed sashes should be too much more than double glazed casements. Personally I'm not a big fan of the casement window look.
In my own home I didn't replace the old existing sashes in the old part of the house. In the newer parts of the house we put in double glazed mahogany windows some fixed and some that open like a door (one large big pane of glass). The rooms that still have single glazing need more heating than the ones that don't. I don't regret having kept the old sashes, but we are in sunny london and I seem to remember you are up in the freezing cold north.
Are you living in the house already? How bad is it now? There is quite a bit you can do to an existing sash to reduce the draughtiness, but of course you can't stop the flow of heat/cold through the glass. Heavy curtains are helpful too.

Jasper-not sofia ames but we have a big draughty very exposed victorian house with sash windows. They have needed replacing for years but we have put it off as long as possible. Now you can actually stick your fingers through the frames so we must do!
Have had quotes for
1)specialist sash window complete replacement with double glazing (2 diff companies)
2) Ventrolla-company who replace and repair leaving most of frames intact, less mess but dont paint etc
3) new windows that are pvc but "look" like painted wood and work like sashes (they did actually look reasonable)
All the above were actually about the same price (£20,000-£25,000)
No one suggested casements. We are in the south but very exposed, windy site.
What we have actually gone for is having a joiner make the windows and a builder fit them. This is about £10,000 cheaper in our case (of course he could make a complete pigs ear of it! - but we are having the 2 ground floor bays done first to make sure ok) might be worth checking this option?

sofiaames and miggy, thank you for your replies.
Miggy I had not thought of that option. I have been looking at the ventrolla website tonight.Looks pretty expensive but also impressive.

Miggy how many windows do yo have and what sort of size are they?

Sofia, yes, we are living here and yes we are in a windy part of Scotland.
The casements the estimator suggested would cost about a third less than replacement sashes, and yes, the frames will need replaced in either case.

I was really surprises he was so against replacement sashes. I will need to see the casements he is suggesting in situ in a house like mine . I can't quite believe they will look like sash windows. Also I have been looking up Scottish buildings regs and wonder if casements with a fixed lower half maybe won't comply.

We have 4 large bay windows-each effectively 3 windows, one large and 2 small, 4 sash windows in dormers and 3 other normal sash windows.
Ventrolla did look good but they only replace bits and leave most of frames if possible. Ours are so bad I was worried may not be enough. Their quote was the cheapest but didnt include painting or stripping back old wood ready to paint which I thought would probably end up being very expensive.
If your sashes are in reasonable nick but you just want them replaced with double glazing, might be worth a quote from them?

jasper-just to let you know they have started today and seems ok so far.
OK they left after 4 hrs having run out of wood as they "didnt realise they would have to take the frame off to get the window in" (slightly worrying)
But actual joiner made window is lovely, chunky,solid double glazed and lovely little curved twiddly bits at the bottom sides of the top sash.
Another slight worry is havent seen a sash mechanism yet (maybe am being picky here-previous ones didnt open anyway as frames too rotten and painted shut!)
Will keep you informed!