Understanding Energy Ratings for Windows and Doors

Energy ratings for windows might seem confusing at first, but understanding them can help you make better decisions for your home.

The Rating System

Windows in the UK are rated from A++ (most efficient) to G (least efficient). Most modern PVC and aluminium windows achieve A or A+ ratings as standard.

What Affects the Rating?

Several factors contribute to a window's energy rating:

• U-value: How well the window insulates (lower is better)
• Solar gain: How much heat from sunlight passes through
• Air leakage: How airtight the window is

Why It Matters

Better-rated windows reduce heat loss, cutting your energy bills and making your home more comfortable. They also reduce condensation and draughts.

Our Recommendation

We recommend A-rated windows as a minimum for most homes. For maximum efficiency, consider triple glazing which can achieve A+ or even A++ ratings.