Measured properly
A careful home survey before anything is ordered.
Smart Systems · Alitherm 400
Aluminium Windows · Gloucestershire
Aluminium Windows in Gloucestershire
Smart Alitherm 400 aluminium windows — slim sightlines, thermally broken profiles and PAS 24:2022 security. Fitted by our own team across Cheltenham, Gloucester, Stroud and all of Gloucestershire.
Quality systems
Trusted British-made Liniar and Smart products.
Fitted by our team
Directly employed installers, never passed around.
Protected afterwards
Clear guarantees and local aftercare when you need it.
Why choose LP Windows
Built to last. Fitted by people who care.
Slim sightlines
Stronger aluminium means narrower frames and more glass — maximum light and uninterrupted views.
Thermally broken
Polyamide break technology delivers U-values as low as 1.4 W/m²K — aluminium warmth without compromise.
PAS 24:2022 security
Every Alitherm 400 window meets PAS 24:2022 enhanced security standards with multi-point locking as standard.
Any colour, inside and out
Powder-coated in any RAL colour, with dual-colour options to match your interior and exterior.
Low maintenance
Aluminium won't rot, warp or need painting — just wipe clean and it stays looking new for decades.
Clear guarantee terms
We explain the product and installation cover that applies to your chosen specification before you order.
About this service
Aluminium windows are the choice for Gloucestershire homeowners who want maximum glass, minimal frames and a finish that lasts for decades without maintenance. We install Smart Alitherm 400 — a British-made, thermally broken system that combines slim sightlines with PAS 24:2022 security approval and U-values as low as 1.4 W/m²K.
From contemporary new builds in Gloucester to barn conversions in the Cotswolds and townhouse renovations in Cheltenham, aluminium windows suit properties where clean lines and architectural integrity matter. The inherent strength of aluminium means we can achieve larger pane sizes and narrower frames than uPVC — ideal for picture windows, bi-fold doors and sliding patio doors.
Smart Alitherm 400 is powder-coated in any RAL colour, with dual-colour options so you can match your interior and exterior. The finish is weather-resistant and colour-stable — it won't fade, peel or need repainting. Thermally broken polyamide technology keeps heat inside, so you get the look of aluminium without the cold bridging that plagued older systems.
As with all our products, aluminium windows are fitted by our own employed team — the same people who survey your home. We're based in Cheltenham and cover all of Gloucestershire. Call 01242 300 535 for a free survey, or visit our shop at 83 Prestbury Road to see Smart Systems products in person.
Explore the possibilities
Product and installation examples.
This gallery includes manufacturer photographs. These illustrate product options and are not all L&P installations.
How it works
Four steps.
No surprises.
Free survey
We visit your home, measure up and listen to what you want. No obligation, no pushy salesperson, no three-hour pitch.
Fixed quote
One written price covering frame, glass, hardware, fitting and disposal — no hidden extras, no countdown timers.
Made to measure
Your windows or doors are manufactured in Britain to your exact sizes, colours and finishes.
Fitted by our team
Installed and cleaned up by our team, with care instructions and the guarantee and installation paperwork that apply to your project.
Guarantees & aftercare
Protected long after we leave.
Product guarantees
We’ll confirm the manufacturer’s cover for your chosen specification in writing.
Installation cover
Ask about the installation guarantee and any insurance-backed protection that applies to your project.
Glass & hardware
Cover can vary by component. We’ll explain the relevant terms before you order.
Aftercare you can rely on
We're a local company you can actually find. Call us and we'll come back — no chasing required.
Good to know
Questions, answered.
Modern thermally broken aluminium windows like Smart Alitherm 400 achieve U-values as low as 1.4 W/m²K — comparable to many uPVC systems. The polyamide thermal break prevents cold bridging, so you get the slim aesthetic of aluminium without sacrificing warmth.
Aluminium is inherently durable and weather-resistant. Powder-coated finishes typically last 25–30 years before needing attention, and the frames themselves can last 40+ years. Unlike timber, aluminium won't rot, warp or need repainting — just wipe clean.
Yes. Smart Alitherm 400 is powder-coated in any RAL colour, and you can choose different colours inside and out (dual colour). Popular choices include Anthracite Grey, Black, Slate Grey and metallic finishes.
Every Alitherm 400 window we install meets PAS 24:2022 — the enhanced security standard referenced in Building Regulations. Multi-point locking is standard, and the inherent strength of aluminium frames makes them highly resistant to forced entry.
Yes. We install Smart Visofold bi-folding doors and Visoglide Plus sliding patio doors — both thermally broken, both with slim aluminium frames. They're perfect for opening up living spaces to gardens and patios.
All of Gloucestershire — Cheltenham, Gloucester, Stroud, Cirencester, Tewkesbury, the Forest of Dean and surrounding villages. We're based in Cheltenham, so most of our work is within a 30-mile radius. Call 01242 300 535 to check your area.
Areas we cover
Serving all of Gloucestershire.
CheltenhamGloucesterStroudCirencesterTewkesburyForest of DeanBishop's CleeveWinchcombePainswickNailsworthDursleyWotton-under-Edge
Free survey & quote
Let's get started.
Tell us what you're planning and we'll arrange a free, no-obligation survey anywhere in Gloucestershire — or pop into our shop and see Liniar, Smart and Future products in person.
Thank you, .
Your survey request is in. We’ll call you back within one working day.