If you’re comparing double glazing in Stevenage, you probably want straight answers to four questions: what will it cost, who can I trust, how long will it take, and will it be done properly? This guide answers all four. It comes from Lee Webber, founder of Design A View, a FENSA-approved and CPA-accredited installer with over 30 years’ experience fitting windows and doors across Stevenage, Hitchin, Letchworth and the wider Hertfordshire area.
The Quick Answers
- Typical cost: £4,000 to £9,000 for a full uPVC replacement on a three-bedroom semi with 8 to 10 windows. Individual windows usually cost £400 to £900 fitted.
- Time on site: Usually one to three days once the windows are made. Manufacture typically takes a few weeks.
- What you should receive: A written quote, a guarantee, and a FENSA certificate confirming the work meets Building Regulations.
- First step: A free in-person survey. Avoid firm prices based on photos or phone calls.
Do You Actually Need New Double Glazing?
Not every problem needs full replacement, and an honest installer will tell you so. Look for these signs:
- Condensation or mist between the panes. The sealed unit has failed. If the frame is sound, replacing just the glass unit can be enough.
- Draughts or cold spots around the frame. Often a sign of worn seals, warped frames or failed fixings.
- Windows that stick, won’t lock or no longer close properly. This is a security issue as well as a comfort one.
- Noise from outside. Older glazing and early units perform poorly against traffic and rail noise.
- Rot, damaged or discoloured frames. Usually beyond economical repair.
If only one or two units have misted, repair is often the better value. If most windows show several of these signs, replacing everything in one project is usually more cost-effective, because access, labour and disposal are shared across the job.
How Much Does Double Glazing Cost in Stevenage?
| Item | Typical fitted price (2026) |
|---|---|
| uPVC double glazed window | £400 – £900 per window |
| Aluminium double glazed window | £700 – £1,500 per window |
| Timber double glazed window | £800 – £1,800 per window |
| Full uPVC house replacement (3-bed semi) | £4,000 – £9,000 |
| Replacement sealed unit only (frames sound) | Around £150 – £350 per unit |
These are guides, not quotations. The main factors that move a price are frame material, window size and style (bays and bespoke shapes cost more), glass specification, access, and any structural work such as lintels or brickwork. For a fuller breakdown, see our window cost guide.
A cheap quote isn’t always a cheaper job. Ask what is missing. Common gaps are thinner frame profiles, standard rather than high-performance glass, no allowance for making good plaster and brickwork, and no FENSA certificate.
How to Choose Double Glazing Installers in Stevenage
Searching for double glazing installers in Stevenage returns national brands, comparison sites and dozens of local firms. Use this checklist:
- FENSA registration. Ask for the registration number and check it on FENSA’s own website rather than relying on a logo.
- A written, itemised quote. It should state what is included, the glass specification, and whether VAT is added.
- An insurance-backed guarantee. A guarantee is only as good as the company standing behind it.
- Qualified fitters. Our installers are qualified MTC fitters, and we are CPA-accredited.
- Reviews that describe real work. Look for detail on tidiness, timekeeping and communication, not just star ratings.
- A local base. We work from Barclay Crescent in Stevenage, so aftercare means a short drive, not a call centre.
Red flags: pressure to sign today for a “special discount”, prices given without a survey, no certificate mentioned, and vague descriptions of the glass.
What Double Glazing Installation Looks Like
- Free survey. We measure every opening and check the brickwork, cills and lintels. In 30 years, Lee has found that most expensive surprises come from skipped surveys, not from the windows themselves.
- Written quote. Clear, itemised, no pressure.
- Made-to-measure manufacture. Units are built to your exact sizes.
- Fitting. Old frames come out, new ones are fitted, sealed and finished inside and out.
- Clean-up and certification. We remove and recycle your old windows, including the uPVC and glass, and register the work so you receive your FENSA certificate.
What to Ask About the Glass
Not all double glazing performs the same. Ask about:
- Thermal performance. Replacement windows in England must currently meet a U-value of 1.4 W/m²K or a Window Energy Rating of Band B. A FENSA installer should meet this as standard.
- Low-E coating, gas filling and warm-edge spacers. These improve insulation and reduce condensation at the glass edge.
- Ventilation. If your old windows had trickle vents, your installer should explain what is required for the new ones.
- Safety glass. Doors and low-level glazing need toughened or laminated glass under Building Regulations (Part K).
- Acoustic glass. Worth considering for rooms facing the A1(M), the railway or a busy road.
Our guide to how new windows improve energy efficiency explains these in more detail.
uPVC, Aluminium or Timber?
uPVC is the most popular choice thanks to value, low maintenance and strong thermal performance. See our uPVC windows and doors. Aluminium gives slimmer frames and a contemporary look, ideal for extensions and renovations. Timber suits period homes and anyone wanting a traditional finish, and is often the right answer where heritage rules apply.
Rules, Certificates and Conservation Areas
Replacing windows must comply with Building Regulations. FENSA registration lets us self-certify this, and the certificate matters when you sell, because buyers’ solicitors will ask for it.
Most homes can replace windows under permitted development, but there are exceptions. Listed buildings need Listed Building Consent, and conservation areas or homes with an Article 4 direction may have extra restrictions. Stevenage Borough Council has designated several conservation areas, including the Town Square (1988), so check the council’s conservation area information for your address before ordering. We have worked on many listed and conservation area properties and will flag any concerns at survey.
Double Glazing in Stevenage: What’s Different Locally?
Stevenage was designated Britain’s first New Town in 1946 and built as six residential neighbourhoods, with Bedwell among the first, from 1952. That means many homes here are post-war, and plenty of owners are now on their second round of windows, or still have early replacements nearing the end of their life. The Old Town has older, more characterful buildings where style and heritage rules deserve closer attention. The town also sits beside the A1(M) and the East Coast Main Line, so noise reduction is a genuine consideration for some homes.
Why Stevenage Homeowners Choose Design A View
We’re a local, family-run business with 5-star Google reviews. Stevenage customers mention tidy fitting teams, punctuality, clear communication and fair pricing, and one recent reviewer noted a warmer, quieter home after their uPVC windows went in. We can usually arrange a survey within 24 to 48 hours, with evening and weekend appointments available. Browse our gallery, meet the team on our About Us page, or see our Stevenage page.