The short version
- Which? says installers are quietest in winter and some may give discounts then.
- Spring and autumn are milder for fitting, and windows can be fitted in winter too.
- We found no published data showing a cheapest month, so compare written quotes.
- Plan back from the date you need the windows in, such as a house sale.
When is the best time to get double glazing quotes?
The best time to get double glazing quotes is as soon as you are planning the job, well before the date you want the windows fitted. Three quotes mean three visits and three written quotes, and the windows are only made after you order and the technical survey is done. Before the first visit, read how to choose a double glazing installer.
Every quote has a validity period. Ask each installer how long its price holds, and get the date on the quote. A quote with a clear validity date lets you compare at your own pace, without a deadline set by the salesperson.
When is the best time of year to have windows fitted?
The best time of year to have windows fitted is a dry spell that suits your household. Each opening stands empty for a time while the old frame comes out and the new one goes in. The season changes what you weigh up, not whether the job can be done.
| Season | What to weigh up | What to ask the installer |
|---|---|---|
| Winter | Which? says installers are quietest now and some may discount. Cold air comes in while each opening is empty. | Is there a lower price for a winter fitting? How long is each window open? |
| Spring | Milder weather for open walls. A good time to book work you want done before the next winter. | What is the current lead time from order to fitting? |
| Summer | Warm, longer days for fitting. Holidays can clash with fitting dates. | Can you confirm the fitting date in writing? |
| Autumn | Some installers market "fit before Christmas" slots with a booking deadline. | Is the deadline about fitting slots or about price? |
Can you fit windows in winter?
Windows can be fitted in winter. FENSA's guidance to installers says installing windows in bad weather "is often possible", with extra precautions:
- Agree it first: the installer checks with you whether you want the windows fitted in the rain.
- Protect the room: a protective cover goes down and furniture and ornaments move away from the work.
- Seal later if wet: sealant is harder to set in the rain, so the installer can fit the window and finish sealing it once it is dry.
- Upper floors: ladders and scaffolding get slippery in wet weather, and FENSA says fitting high windows in poor conditions is often unsafe unless the whole job can be done from inside.
- Doors: a doorway leaves a bigger gap, and FENSA says doors should only go in during good weather or very light rain.
Ask each installer how it protects each opening, whether it fits one room at a time, and what happens to the fitting date in heavy rain or frost. Get the answers in writing with the quote. On exposed coasts the spec matters too: our page on double glazing in Aberdeen covers wind, rain and salt on frames and hardware. Cardiff averaged 1,201 mm of rain a year from 1991 to 2020, so our page on Cardiff double glazing quotes asks every installer for the watertightness class of the windows quoted.
Are winter double glazing discounts real?
Winter discounts on double glazing are possible but unproven. Which? says "most installers are most quiet in the winter months and may be willing to give discounts", but gives no figures. We found no published data on double glazing prices by month, so the size of any winter discount is unknown.
Test it yourself instead. Ask each installer for a written price for a winter fitting date and the date the price is valid until, then compare the quotes side by side. A "discount" that only applies if you sign today is a sales tactic, not a seasonal saving.
Plan back from the date you need
Work back from the date the windows have to be in. Allow for the quotes, the technical survey, manufacture and the fitting itself. Our guide on how to compare double glazing quotes covers the quote stage. Our sister site sets out the double glazing installation process stage by stage. Three dates drive most timing decisions:
- Selling the house: your solicitor asks for the Building Regulations certificate from FENSA, CERTASS or another competent person scheme, so leave time for it to arrive.
- Before the heating season: book early enough that the fitting date falls before the cold weather you are trying to keep out.
- Other building work: fit the windows before decorating, so making good does not spoil new paint or plaster.
If you sign at home, you usually have at least 14 days to cancel, but made-to-measure windows can be an exception, so check the contract before you sign. The double glazing cooling off period guide explains how that affects an early fitting date.
Start comparing quotes now
Getting quotes early costs nothing and keeps your options open. Get double glazing quotes from local installers who cover your postcode, free and with no obligation. Before the visits, read the questions to ask a double glazing salesman.
Questions people ask
What is the cheapest time of year to replace windows?
No time of year is proven to be cheapest for replacing windows, because we found no published price data by month. Which? says installers are quietest in winter and some may give discounts, so ask for written prices with a validity date and compare them.
Is it okay to install windows in winter?
Installing windows in winter is fine. FENSA says fitting in bad weather "is often possible" with precautions, such as protecting the room and finishing the seal once it is dry. Doors are the exception, and FENSA says they should only go in during good weather or very light rain. See can you fit windows in winter for what to ask.
How far ahead should I book double glazing?
Book far enough ahead to cover three quotes, the technical survey and manufacture before your target date. Ask each installer for its current lead time in writing.
