What Does Double Glazing Cost? Supply & Fit UPVC Windows

Double Glazed Sash Windows

How much do Sash Windows cost?

The most recognisable aspect of Sash Windows design is the way they open by sliding the windows vertically in order to open or close. Traditionally the weight of the moving glazed sections was counter balanced by cast iron weights on ropes which were built into the surrounding frames.

sash windows upvc

Double Glazed Sash Windows

Typical problems with older sash window designs

Many older wooden versions of this design gave problems with the moving sections either sticking in the tracks or becoming loose and allowing penetration by both water & wind, making them a nightmare during the winter. Where cast iron weights are built into the frames, as a counterbalance to the moving window section, the ropes connecting them to the window fray and rot. This eventually causes the weight to become disconnected and the windows drop out of position.

Happily, modern versions for replacement windows have resolved all the issues by means of spring loaded tensioners instead of weights and smooth operation of the guide track in the frames.

Sash windows cost & pricing factors

The amount of money you will need to spend depends upon a number if things and also whether you are refurbishing / upgrading an existing unit or going for a full replacement.

Upgrading an existing sash window

To begin with, it may be worthwhile to consider if refurbishing your existing sashes is a viable option. If they are “too far gone” then you may have no choice but to replace them. However, if the wood is in decent condition and it’s just a matter of functionality or upgrading to double glazing there are ways to do this that can cost less than a full replacement.

How much does secondary glazing for a sash window cost?

Adding internal secondary glazing is an option that has been successfully used many times in many homes. The approximate cost to fit secondary double glazed panels the the interior of a sash window can start around the £200 to £250 per square metre mark.

Replacement sash window options

Broadly you have 3 primary designs: Single hung where one window section moves (usually the bottom one) – Double Hung, where both window sections move – Horizontal, where the windows move side to side.

How much does a timber box sash window cost?

In addition to this you could be looking at Box Sash windows, usually made from timber in a traditional appearance or Slimline sashes which are prominent in uPVC Sash Window units.

A proper refurbishment of a timber box sash window is not necessarily a cheaper option than replacing the unit. If there is significant work to be done (and you will need a specialist) then don’t expect the cost to be under a few hundred pounds per window at least.

Box sash windows made from timber are quite involved to manufacture and therefore are usually priced higher than a typical uPVC sash equivalent – prices for a single timber box sash window unit can start at £500 for a good quality example.


Single Sash: 60cm x 100cm – B energy ratedWhite uPVCfrom £200 – supply only
Single Sash: 90cm x 100cm – B energy ratedWhite uPVCfrom £250 – supply only
Single Sash: 120cm x 10cmm – B energy ratedWhite uPVCfrom £270 – supply only
Single Sash: 150cm x 100cm – B energy ratedWhite uPVCfrom £300 – supply only

Bearing in mind that labour prices for the removal of the old window and installation of the new window can make up a high percentage of the overall cost of replacing a sash window you could expect the fitted cost to be around twice that of the supply only cost.

Points to note

Some properties in certain areas of the UK will have restrictions on the type of changes that you can make to the appearance of (and the material used to replace) new windows. For example, if you live in a listed building or are located in an AONB (Area of Outstanding Natural Beauty,) there could easily be local restrictions in force. If you are unsure, please check with your local planning department before doing anything.

Find out more about French Windows or Tilt & Turn Windows for your home

double tilt sashBecause manufacturing processes are to a high standard and with the impact of UK building regulations, you can now be confident in the thermal performance of new sash windows, as they are built to keep in the heat & keep out the weather at a reasonable cost for double glazed windows.

Latest innovations in design allow the moving glazed panels to detach from the guide tracks via special hinges and this feature adds a tilting & turning function so that the windows can be easily cleaned from the inside of the room & in some instances can be very useful as a means of escape in the event of an emergency.

Options for Colours & Surface finishes

UPVC Sash Windows can be made in a choice of colours and feature wood-grain surfaces which gives them a very authentic look which is becoming accepted for use in places where local planning authorities would not have considered them before.

As you would expect, security is much improved with locks that are built to keep intruders out and, should you want to upgrade to toughened or laminated glass you can easily do so.