Performance & Energy Efficiency
Windows that work
harder for you.
Modern A-rated windows and thermally optimised doors aren't just better for the environment — they cut your heating bills, improve comfort, and reduce condensation. Here's how ours do it.
AWER
Window Energy Rating
0.8W/m²K
Best available U-value
94%
Less edge heat loss vs aluminium spacers
30%
Better insulation with argon gas fill
How It's Measured
The numbers that matter
Energy performance in windows and doors is measured in three ways. Understanding them helps you compare products accurately — and spot claims that don't stack up.
Window Energy Rating
All our standard UPVC and aluminium windows achieve an A Window Energy Rating (WER) — the highest band available. A-rated windows lose significantly less heat than C or D-rated alternatives.
WER Band A+, A or equivalent
U-Value Performance
U-value measures how quickly heat escapes through a window or door. Our double and triple glazed units achieve U-values as low as 0.8 W/m²K — well below the 1.6 W/m²K required by Part L of the Building Regulations.
As low as 0.8 W/m²K
Solar Heat Gain
Modern low-emissivity (Low-E) glass coatings let in free solar warmth during winter while reflecting excess heat in summer. The right balance of solar gain reduces your heating load without overheating your home.
Optimised g-value coating
How we build it in
Six layers of thermal performance
Every product we install combines multiple technologies. Remove any one of these and performance drops. Together, they make the difference between a window that performs and one that merely looks good.
Thermally Broken Frames
Our aluminium window and door frames use a thermal break — a section of low-conductivity material separating the inner and outer aluminium profiles. This eliminates cold bridging and prevents condensation on frame edges.
Warm-Edge Spacer Bars
The spacer bar that holds the two panes of glass apart in a double-glazed unit is a significant source of heat loss and condensation. We specify warm-edge spacers — typically Super Spacer or ThermoBar — which reduce edge-of-glass U-values by up to 94% compared to standard aluminium spacers.
Argon-Filled Cavities
The gap between panes in a double-glazed unit is filled with argon gas rather than dry air. Argon is denser and conducts heat less readily than air, improving the unit's centre-pane U-value by approximately 30% without any change in visible appearance.
Low-Emissivity (Low-E) Glass
Low-E glass has an invisible metallic coating on the inner pane that reflects radiant heat back into the room. In winter this keeps warmth in; in summer it reflects solar radiation out. The result is a more comfortable interior temperature year-round with less reliance on heating and cooling systems.
Multi-Chamber UPVC Profiles
Our UPVC window frames use multi-chamber profiles with a minimum of five inner chambers. These chambers trap air and act as natural insulators — reducing heat transfer through the frame itself and contributing to the overall Window Energy Rating.
Draughtproofing & Sealing
Even the best glass unit is undermined by poor sealing. Our installers use high-quality compression seals and weatherstripping throughout, ensuring that draughts — one of the biggest sources of heat loss in older windows — are eliminated at the point of fitting.
Old vs New
What replacing your windows actually changes
Beyond heat loss
Security and weather resistance, built in
High-performance glazing and frames don't just keep heat in — they keep intruders out and weather at bay. All our windows and doors meet or exceed current Building Regulations for security.
PAS 24 Security Standard
Our doors and windows meet PAS 24:2022 — the enhanced security performance standard specified by Secured by Design and required for Part Q compliance on new builds and many planning applications.
Multi-Point Locking
All our doors use multi-point locking systems that engage at multiple points along the frame simultaneously. Significantly harder to force than single-point locks.
Toughened & Laminated Safety Glass
Glass near doors and low-level in windows is specified as toughened or laminated safety glass in accordance with BS 6206, protecting against accidental impact and forced entry.
Weather-Resistant Seals
Our compression seals and weatherstripping are tested to Class 4 air permeability and Class E1500 wind load resistance, keeping draughts and rain out even in exposed locations.
Secured by Design
Police-preferred specification. Multi-point locking as standard on all doors.
Weather Tight
Class 4 air permeability. Tested for wind-driven rain resistance to E1500.
Acoustic Performance
Laminated acoustic glass options reduce external noise by up to 46dB Rw.
Building Regulations
All installations comply with Part L (energy), Part Q (security), and Part N (safety glazing).
Upgrade your home
Ready to cut
your energy bills?
Free home survey. Written quote within 48 hours. A-rated products installed by FENSA-registered fitters.