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In the sixth of the series of blog posts regarding retrofitting homes to be more sustainable, PJH are looking at glazing comparisons (double vs triple glazing). Beginning with an introduction and facts regarding glazing, pros and cons, costs and additional considerations.

Glazing Comparison Introduction

Double glazing vs triple glazing, the panes of glass are sealed within a frame that contains a pocket of air or inert gas between the panes. This gas is usually argon which is heavier than air and therefore offers greater insulation to both heat and noise. With the third pane of glass in triple glazing offering an additional pocket, according to Everest (2023) upgrading to triple glazing adds around 25% efficiency.

glazing comparison

There are several variations that can alter both types of glazing in order to achieve greater results for insulating a home for heat and noise. The type of gas that is used can increase thermal performance, the spacers between the frames can be upgraded to ensure that it reduces thermal bridging and there are different coatings available for the glass panes that offer increased performance. Frames themselves can also have added or unexpected effects to the overall performance with insulated frames ensuring reduced thermal bridging and greater air tightness.

Glass manufacturers have been able to develop various different coatings that can offer the end user reduced glare, reflecting unwanted solar gain, self-cleaning glass and increased insulation performance. The Building Regulations require that windows now must have a minimum U-value of 1.4 as a result of the increasing achievable performance from manufacturers.

glazing comparison

Pros and Cons of Triple Glazing

glazing comparison

Glazing Comparison: Associated costs

The costs for double and triple glazing can vary depending on the different optional extras that can be included. According to Checkatrade (2023) the cost for a triple glazed window can be around £485 per window with double glazing coming in at around £325 per window, averaging around £160 (or 49%) more expensive for triple glazing.

Loftera (2023) state that costs would typically be around £80 per m² (excluding installation) for double glazing. Whilst some window specialists might be able to provide a cost per m², it’s always better to get a personalised quote from your chosen manufacturer.

Additional considerations for Glazing Comparison –

Requirement for ventilation as per updated building regulations

As per the Building Regulations Approved Document F, the updated regulations regarding ventilation which took effect from 15th June 2022 requires properties to allow for consideration of the ventilation when installing new windows. Whole dwelling ventilation needs to be considered which can be delivered through natural ventilation, mechanical ventilation or a combination of both. Natural ventilation within window systems would be trickle vents to ensure the input of fresh air to dilute, disperse and remove water vapour and pollutants not removed by mechanical extraction.


To conclude the glazing comparison, whilst double glazing can achieve the current required u-value in order to satisfy the building regulations, triple glazing can offer customisable benefits that double glazing can’t. Whilst being better at insulating a dwelling to prevent heat loss, triple glazing can also offer reduced; noise, glare, solar gain, thermal bridging. In conjunction with other eco retrofits, installing triple glazing windows can have a profound effect on the indoor climate making it easier to maintain at a comfortable level. This will in turn have an effect on monthly bills, running costs and the carbon footprint of the dwelling.

Ask us for advice

If you have a project in its infancy and want to have an informal chat regarding your options, feel free to contact us, we are always happy to provide friendly and knowledgeable advice. Get in touch on 0161 460 0382 or email the team at enquiry@pjhas.co.uk 

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