Energy Saving Calculator

Cost Saving Secondary Glazing Calculator

To work out the cost saving for the whole building, simply enter the details of the property.

Type of Primary Window
Taken from the Pilkington Spectrum Glass uValue calculator using 4mm Optifloat clear annealed for single glazed and Air filled 4mm Optifloat clear annealed for double glazing.

Timber single-glazedAluminium single-glazedSteel single-glazedSteel double-glazeduPVC single-glazeduPVC double-glazed

U Value W/(m²K) Primary & Secondary Window Combined
U-Value based on Granada’s slimline hinged unit, with 6mm low-e glazing and a 50mm cavity.

How many windows do you have?
Based on average window dimensions of 2000mm x 1000mm

External Temperature Summer

External Temperature Winter

Internal Temperature
Based on lower external average temperatures of 2°C Winter and 9°C Summer.

The below is based on 6 months in summer and 6 months in winter

Heating (Hours per Day) in Summer

Heating (Hours per Day) in Winter

Unit Cost Per kWh (£)
Current UK average as of Oct 23.

Average Estimated Saving in GBP (Per Day)

Estimated Saving in GBP (Per Annum)

Calculation in Watts (Primary Only)

Calculation in Watts (Combined)

Calculation in kW (Primary Only)

Calculation in kW (Combined)

kWh Per Day (Primary Only)

kWh Per Day (Combined)

kWh Per Annum (Primary Only)

kWh Per Annum (Combined)

Saving in kWh (Per Day)

Saving in kWh (Per Annum)