The best time to replace windows in the UK is usually during spring or autumn. These seasons offer mild temperatures and more predictable weather, helping your installation go smoothly with minimal disruption to your home.

Why Spring and Autumn Are Ideal for Window Replacement

Spring and autumn provide the perfect balance for window upgrades. Installations are less likely to be delayed by extreme weather, and your home is less affected by cold drafts or overheating during the fitting process.

Other benefits include:

  • Comfortable internal temperatures while windows are briefly removed
  • Lower condensation levels for proper sealing
  • Greater installer availability compared to peak times

At Cristal Windows, we find that homeowners often book in early spring or mid-autumn to prepare their homes for either summer heat or winter cold.

Is It Bad to Replace Windows in Winter or Summer?

It’s not necessarily “bad” — but there are more challenges.

Winter replacements are possible, but you may experience:

  • Colder indoor temperatures during installation
  • More unpredictable weather delays
  • Damp conditions that may affect certain materials

Summer installations can be affected by:

  • High demand (longer lead times)
  • Installer availability issues during holidays
  • Intense heat that could expand window frames temporarily

That said, Cristal Windows uses a one-at-a-time fitting method, so even winter installs only expose one room at a time to outside air.

When Should You Book Your Window Installation?

The best time to book is at least 6–8 weeks in advance of your preferred installation window. If you want your windows fitted before winter, aim to book by early September. For summer-ready upgrades, spring is the ideal time to act.

At Cristal Windows, our typical lead times are:

  • 4–6 weeks for standard uPVC windows
  • 6–8+ weeks for bespoke timber or aluminium orders
  • Varies depending on demand and product type

Booking early ensures a smoother process and guarantees your place in our schedule.

Can You Replace Windows in Bad Weather?

Yes, experienced installers like ours are equipped to handle light rain, cold temperatures, and windy days. If weather conditions are severe, we’ll reschedule to maintain quality and safety — but most UK conditions are manageable with the right tools and protection.

Cristal Windows fitters use:

  • Temporary weather shields
  • Quick-fit methods to limit exposure
  • Proper insulation and sealing, no matter the season

You don’t have to wait for a heatwave to improve your windows!

Choose the Season That Suits Your Schedule

While spring and autumn offer the smoothest experience, the best time to replace your windows is when it suits your needs and timeline. If you have a draughty home or rising energy bills, don’t wait — Cristal Windows installs high-quality double and triple glazing all year round.

Ready to upgrade your windows?

Get a free quote today or call our team to discuss the best installation time for your home.