Double glazing buyer's guide

Everything a UK homeowner needs to buy double glazing well: what to specify, what the rules require, what affects the price, and how to compare quotes like for like. Read it in order, or jump to the guide you need.

Start with the four decisions

Almost every double glazing quote comes down to four choices: the frame material, the glass and sealed-unit specification, the window style, and the standard of installation. Get a view on each before an installer visits, and you will read any quotation on its merits rather than on a salesperson's script. This buyers guide walks each decision in turn, then shows you how to turn that understanding into quotes you can trust.

If you are completely new to the subject, begin with double glazing explained, which sets out how a sealed unit actually works and why the gap between the panes matters more than most people think.

Frames, glass and styles

The frame carries the window and shapes both its look and its upkeep. Our guide to window frame materials compares uPVC, aluminium and timber on cost, appearance, lifespan and maintenance, so you can match a material to your home and budget.

The glass does the thermal and acoustic work. Low-emissivity coatings, argon fill, warm-edge spacer bars and — where it is worth it — triple glazing all change how a unit performs. Our guide to double glazing glass types explains each in plain terms. Finally, the shape of the window matters for ventilation, cleaning and kerb appeal: see the full range in our UK window styles guide, covering casement, sash, tilt-and-turn, bay and more.

Rules, certification and longevity

Replacement windows in England and Wales must meet Building Regulations for energy efficiency, ventilation and safety. Our guide to building regulations for windows sets out what the rules require, and FENSA and CERTASS explained covers the competent-person schemes that certify the work and issue the certificate you will need when you sell.

Longevity matters too. Read how long double glazing lasts for realistic lifespans of units, frames and seals, and when to replace double glazing for the tell-tale signs — misting between the panes, draughts, stiff handles — that mean it is time.

The full guide index

• Double glazing explainedWhat it is and how a sealed unit works.
• Frame materials compareduPVC vs aluminium vs timber, side by side.
• Glass typesLow-E, argon, triple, acoustic and toughened.
• UK window stylesCasement, sash, tilt-and-turn, bay and beyond.
• Building regulationsWhat the rules require for replacements.
• FENSA & CERTASSCertification schemes and why they matter.
• How long it lastsRealistic lifespans for units and frames.
• When to replaceThe signs it is time for new windows.
• Getting quotesHow to gather and compare UK quotes.

Then compare quotes properly

Once you understand the four decisions, the last step is gathering several written quotes after a proper home survey and comparing them on the same specification. Our guide to getting double glazing quotes in the UK explains how to do that without pressure — and how funding and contribution options work, subject to eligibility and a home survey.