You can replace the windows in a flat, but the first step is rarely choosing a window. It is finding out who owns them. In a leasehold flat the windows are often the freeholder's responsibility and need written consent. In a rented flat, replacing them is usually the landlord's decision. Only once that is settled do planning, building regulations, access and price come into play. This guide takes those in order, so you know what to ask before you collect quotes.
TL;DR
- Leaseholders: check your lease and get written permission from your landlord, freeholder or management company before any work starts.
- Planning: flats have no permitted development rights for windows. Like-for-like replacements usually need no planning application, but changes to design, materials or opening style often do.
- Tenants: replacement windows count as an improvement, so you need the landlord's agreement in writing. Landlords must keep the window structure in repair.
- Access: scaffolding, parking, lifts and neighbours' notice affect both the schedule and the price, so tell every installer about them.
- Quotes: give each installer the same brief and compare like with like, including the FENSA or CERTASS registration.
Table of Contents
- Who is responsible for the windows in your flat?
- Replacing windows in a rented flat or house
- Do you need planning permission for flat windows?
- Which style of window suits a flat?
- Can you replace just the glass?
- Access issues to plan for in a flat
- What affects the cost?
- Is it cheaper to replace all windows at once?
- Our perspective
- Compare quotes for your flat
- A short checklist before you order
- FAQ
- Sources
Who is responsible for the windows in your flat?
Start with your lease or tenancy agreement, because everything else follows from it.
In many leasehold flats the freeholder owns the external walls and frames, and the lease says what the leaseholder may and may not alter. Leases differ. Some treat the whole window as the building's responsibility, others split the frame from the glass. That is why a neighbour's experience in the same block may not match yours.
If you are a leaseholder, the national guidance is clear that you may first need permission from your landlord, freeholder or management company. Local authority landlords put this in writing. Lambeth's leasehold guidance says the lease requires written permission before changes to your home, including fitting new doors and windows, and that the council may ask you to reinstate the original at your own cost if the work does not meet its standards.
Haringey makes a point many people miss. Its alterations policy says that neither planning permission nor building control certification gives a leaseholder the right to do the work without the landlord's consent first. Planning consent and landlord consent are two separate approvals.
When the whole block is being done
Sometimes the freeholder replaces every window in the building under a planned scheme. Even if your own flat is excluded, Lewisham Council states that you may still have to pay a proportion of the cost of renewing the other windows under the terms of your lease, and possibly contribute towards access costs and associated works. If your block is in a scheme like this, ask the managing agent for the programme and your expected share before you spend money on your own project.
Replacing windows in a rented flat or house
Tenants often ask two things: can I do it myself, and does my landlord have to do it?
Does the landlord have to replace old windows? Not necessarily, but they do have to keep them in repair. GOV.UK says a landlord is always responsible for repairs to the structure and exterior of the property. Citizens Advice lists windows and doors among the major repairs a landlord handles, and says the tenancy agreement cannot remove that duty or pass the cost to you.
There is a limit. Under section 11 of the Landlord and Tenant Act 1985, a landlord is not obliged to replace an item that can be repaired, and may replace on a like-for-like basis. So a draughty but working window may be repaired rather than replaced. A broken or failing one is a repair request, and you should make it in writing.
Can a tenant replace windows? Only with permission. Shelter explains that replacement windows are an improvement rather than a repair, that the landlord generally does not have to make improvements but you can ask, and that you need their permission even if you plan to pay. Get that agreement in writing. Shelter warns that without it the landlord might ask you to change things back, keep your deposit or try to evict you.
If you are a landlord with a leasehold flat, you need the freeholder's consent as well, so the chain runs tenant, landlord, freeholder.
Do you need planning permission for flat windows?
Householders in houses can often replace windows without applying. Flats are different, because they do not have the same permitted development rights.
Lambeth Council states that like-for-like replacements do not need planning permission, but because flats lack permitted development rights, planning permission will normally be needed if the design, method of opening, materials or profile differ. The Planning Portal says the same in plainer terms: identical windows should not need an application, but different appearance or size, such as new glazing patterns, may do.
In practice, these are the changes that tend to trigger a conversation with the planning team:
| Change | Likely to need planning? |
|---|---|
| Same design, opening style, material and colour | Usually not |
| Timber sliding sash swapped for a top-hung casement | Likely |
| Different glazing bars or frame profile | Likely |
| Different frame material or colour | Likely, check with your council |
| Internal secondary glazing | Not usually |
Conservation areas and listed buildings add further controls, so contact your local planning authority before ordering. Rules are set locally, and the Planning Portal page is the national starting point.
Building regulations and installer registration
New windows must meet thermal insulation standards. Lambeth advises that replacement windows generally have to comply with Building Regulations insulation standards and will usually need to be double-glazed, with exemptions for heritage assets.
This is where installer registration matters. Lewisham requires leaseholders to use a FENSA-registered or equivalent company, to hold public liability insurance, and to supply a method statement for any scaffolding. Freeholders elsewhere ask for much the same, so a registered installer with insurance in place makes the consent process smoother.
Which style of window suits a flat?
In a flat the question is often not "what do I want?" but "what will be accepted?"
Lambeth's guidance sets out what a freeholder or planning team typically wants to see. Replacements should fit neatly into the existing openings, follow the original style of opening such as sliding sash or hinged casement, and copy the frame dimensions and detailing as closely as possible. It also asks for unobtrusive, security-rated locks and fittings, and avoiding visually obtrusive trickle vents on heritage buildings. On older or listed buildings it says that if the new windows do not accurately reproduce the originals, permission is likely to be refused.
That shapes your choice of material:
- uPVC: the common choice for modern blocks, where it often matches what is already there. Check that the colour and profile match your neighbours' windows.
- Timber: often expected in period conversions and conservation areas, particularly for sash windows.
- Aluminium: slim frames suit larger modern openings and balcony doors. Related patio and balcony door questions are covered in our guide to replacement patio doors.
Whatever the material, ask for sizes and finish to be written on the quote so they can be matched against the consent you were given.
Can you replace just the glass?
Sometimes, yes. If the frame is sound and the problem is a misted or failed double-glazed unit, the sealed glass unit can be swapped without replacing the whole window. That can also keep the outward appearance identical, which is helpful when your freeholder wants no visible change. Even so, tell your landlord or managing agent first, since your lease may still treat the glazing as something you need consent for.
If the frame is rotten, warped or no longer closes properly, a new glass unit will not fix it and a full replacement is the better route. A surveyor or a registered installer can tell you which applies when they see the window in person. Ask each installer to quote both options if you are unsure.
Access issues to plan for in a flat
Access is where flat projects differ most from house projects, and where quotes diverge. Raise these with every installer at the first call.
- Floor level and lifts. Fitters carry frames and glass up stairs or in a lift. Large panes on upper floors can be awkward, and the installer needs to know early whether a goods lift or stairs are available.
- Scaffolding or access equipment. Upper-floor windows may need external access. Lewisham asks for a method statement for any scaffolding, so the freeholder will expect to see it. If other flats' windows are being done as part of a block scheme, ask whether shared scaffolding can be used.
- Parking and delivery. Controlled parking, narrow roads and loading restrictions all affect the day. Mention permits or restrictions upfront.
- Communal areas. Halls and entrances need protecting, and the managing agent may restrict working hours or noise.
- Neighbours. Tell the flats below and beside you when work is planned.
- Balconies and shared walls. If windows open onto a balcony or sit on a shared structure, check who is responsible for them.
Good installers cope with all of this routinely, but only when they know about it before pricing.
What affects the cost?
We do not quote fixed prices here, because a flat's cost depends on specifics, and a vague average would mislead you. The things that move a quote are:
- the number and size of windows
- the frame material and finish, and whether it must match the original
- the opening style, such as sash or casement
- glass specification and security fittings
- access: floor level, scaffolding and delivery
- whether old frames contain features that need extra making good
If you are a leaseholder, add any permission fee the freeholder charges, and any contribution to block-wide works under your lease. Lewisham, for example, says leaseholders may also have to contribute towards access costs.
The most reliable way to know your own figure is to compare several written quotes for an identical brief. We explain how in our guide to window installation quotes.
Is it cheaper to replace all windows at once?
Often it is more efficient, because installers can set up once, bring the access equipment once and keep the same crew on site. For flats that matters, since access is a significant part of the job. Ordering one consistent set also helps your windows match, which freeholders and planning teams like. If budget is tight, do the worst windows first, but ask each installer what a staged job would add compared with one visit.
Our perspective
Most people start a flat window project by looking at frames. We think the better first move is to sort out the paperwork and the brief, because that is where quotes go wrong.
Flats bring consent, matching rules and access that a house does not have. If five installers each price a slightly different job, the cheapest quote tells you nothing. A single, clear brief, covering the number of windows, the opening style, the floor level and any scaffolding, gives you quotes you can compare line by line.
That is why we built our service around three simple steps: tell us what you need, get matched with local installers, and compare the quotes. We only include vetted local installers certified with FENSA and/or CERTASS, and the service is free and carries no obligation for homeowners. It saves you phoning round, and it gives you a real picture of local prices, which we say can save you up to £2,000 on an installation.
Show the freeholder a registered installer, a like-for-like specification and a clear written quote, and the consent conversation becomes much easier.
James
Compare quotes for your flat
Once you have your consent and know what you are replacing, the next step is finding installers who will price it properly. Our free comparison service collects your project details, matches you with vetted local installers certified with FENSA and/or CERTASS, and lets you compare their quotes side by side. There is no charge and no obligation.
When you fill in the form, mention that it is a flat, which floor, whether there is a lift and whether scaffolding may be needed. Start your free comparison and see the quotes for your area.
A short checklist before you order
- Read your lease or tenancy agreement for who owns the windows and what consent is needed.
- Ask the landlord, freeholder or managing agent for written permission, and ask what they require, such as plans, insurance details or a method statement.
- Check with your local planning authority whether your like-for-like or changed design needs an application.
- Decide on frame material, opening style and colour to match the existing windows.
- Give every installer the same brief, including access details.
- Ask whether each is FENSA or CERTASS registered and holds public liability insurance.
- Keep the consent letter, the signed quote and the installation certificate together. You will need them if you sell.
FAQ
How much does it cost to replace windows in a flat?
It depends on the number and size of windows, the material, the opening style and how hard the flat is to reach. Leaseholders may also owe a contribution to block works or a permission fee. The dependable way to find your price is to compare several written quotes for the same specification.
Do I need my freeholder's permission to replace windows in a leasehold flat?
In most cases, yes. Check your lease, as many require written consent before you alter windows, and councils as landlords state this explicitly. Planning permission or building control approval does not replace the landlord's consent.
Do landlords have to replace old windows?
Landlords must keep the structure and exterior, including windows, in repair, and tenants cannot be made to pay for that. They are not generally required to upgrade a window that can be repaired. Report faults in writing and keep a copy.
Can I replace windows in a rented house myself?
Only with your landlord's written agreement, because replacement windows count as an improvement. Without it, you risk being asked to reverse the work or losing your deposit.
Do I need planning permission for windows in a flat?
Not usually for like-for-like replacements. Flats lack permitted development rights, so changes to design, materials, opening style or size often do need permission. Ask your local planning authority before you order.
Sources
- Planning Portal: I want to change the windows of my flat
- Lambeth Council: Replacing the windows in a flat
- Lambeth Council: Leasehold alterations guidance
- Lewisham Council: Making alterations
- Haringey Council: Alterations policy for leaseholders
- GOV.UK: Private renting, repairs
- Citizens Advice: Check if your landlord has to do repairs
- Shelter England: Repairs under section 11
- Shelter England: Landlord responsibilities for improvements
- Shelter England: Making improvements to your rented home