Compare aluminium window and door specifications from Cortizo, Smart Systems, and Aluprof — the three system houses we manufacture from in-house at our Slough workshop. Match opening size, U-value, frame depth, sightlines, and operation to your project. Used by architects writing project specifications, contractors sizing for tender, and homeowners exploring options for renovation across London, Kensington, Cobham, Richmond, and the Home Counties.
A live filter and comparison interface backed by the actual systems Direct Trade Windows manufactures — not a generic catalogue.
Filter by U-value, frame depth, and operation to write specification clauses. Download a system-specific spec sheet that maps to Cortizo, Smart Systems, or Aluprof catalogues. Useful at RIBA Stage 3–4.
Size systems against the architect's tender drawings. Confirm sightlines, glazing thickness, and accessory compatibility before pricing. Output is a one-page sheet to attach to a quotation.
Explore which aluminium system fits the opening you're replacing. No jargon barrier — pick by what the window looks like, then read the technical detail. Useful before requesting a quote.
Lower is better. Standard double-glazed aluminium ranges 1.4–1.8 W/m²K. Triple-glazed Cortizo Cor 80 or Aluprof MB-104 reaches 0.9 W/m²K — Passivhaus territory.
The aluminium profile depth front-to-back. Slimmer (52mm Alitherm Heritage) for steel-look heritage. Deeper (104mm Aluprof MB-104) for Passivhaus and oversized panes.
The visible interlock between sashes. 20mm Cortizo COR Vision is the slimmest sliding-door sightline currently fabricated in the UK. 70mm sash interlocks read more traditional.
Casement, tilt-and-turn, vertical sliding sash, sliding, bi-folding, pivot. Each has a different sealing, ventilation, and obstruction profile. Match to use case (egress, ventilation, glass-area maximisation).
Once you've identified the system, see the live product page for project examples, lead times, and pricing context.
Alitherm Heritage · Cortizo Cor 70
Cortizo COR Vision · 4600 · 4700
Smart VS600 · Cortizo Cor 70 Hidden Sash
In-house arch and curve bending
Smart Visofold 1000 · 6000
Frameless structural glass