Sash window costs depend mainly on the size of each window, whether you need a full replacement or a repair, and the condition of the frame. A new window costs more than a repair. The only way to know what yours will cost is to measure your opening and describe what needs doing.
What changes the price of a sash window?
Four things move the cost. The first is size: a small sash window costs less than a large one. The second is what the frame needs: if the wood is sound and the sash slides freely, a repair costs far less than taking the whole window out and building a new one. The third is the material: hardwood costs more than softwood. The fourth is access: if the window is on the ground floor and easy to reach, the work takes less time than one high up or in a tight space.
A window with rot in the frame, or one that sticks or rattles, needs a proper look before anyone can quote. A photograph or a description of the problem helps, but a tradesperson should see it face to face to know what can be saved and what must come out.
Why do two firms quote differently for the same window?
They may be pricing different work. One firm might repair the existing frame and replace only the sash. Another might replace the whole window, frame and all. A third might use a different material or a different construction method. A good tradesperson will tell you exactly what they are doing and why, so you know what you are paying for.
Price also depends on how the firm runs. A business with high overheads will charge more than one that works lean. Neither is wrong: you pay for what you get. The risk for you is paying without knowing what the job includes. That is why it matters to be clear about what needs doing before you ask for a price.
How do you get a fair quote without visiting every firm?
Measure your window opening width and height. Look at the frame and the sash, and write down whether the wood is solid or showing rot, whether the window slides smoothly or sticks, and whether it closes tightly or rattles. Take a photograph if you can, facing straight at the window.
A careful business will give you a way to enter this information on their website and get an estimate back. If what you describe turns out to be right when they visit, that price should not change. This only works if the business has built the tool honestly, using real costs from real jobs, not a guess.
When should you ask a tradesperson to visit?
After you have a rough idea of cost from an estimate. A visit costs time and may cost a call-out fee. If you already know the ballpark price, a visit becomes a proper survey where the tradesperson can see what the estimate missed and give you a final quote.
If your window is complex, very large, in a difficult position, made of wood that is partly hidden, or part of a listed building, a visit may be the only way to be sure. A good tradesperson will tell you upfront whether an estimate is possible from a description, or whether they need to see it in person.
What should a sash window quote include?
The quote should name the window opening size, describe what will be done (repair, full replacement, or something in between), name the materials, and set out the total price. It should say when the work will start and how long it will take. It should be clear about what is and is not included, for example, whether the quote covers taking out the old window, making good the wall, or decorating afterwards.
Ask if the price will change if the tradesperson finds hidden rot or damage once the work starts. A firm that has quoted jobs like yours before will know how often this happens, and can tell you the risk. This conversation costs nothing and matters a lot.