How Much Difference Can New Windows Make?

 

Modern double and triple glazing can perform significantly better than older single-glazed or poorly sealed windows.

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Benefits can include:

• reduced heat loss

• fewer draughts

• improved comfort near windows

• reduced outside noise

• improved security

• reduced condensation on the glass

• better overall appearance

• improved energy performance

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However, the actual benefit depends on what you are replacing.

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Replacing badly fitting single glazing can make a noticeable difference.

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Replacing reasonably modern double glazing with slightly better glazing may produce a much smaller improvement relative to the cost.

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Double Glazing or Triple Glazing?

 

Triple glazing generally provides better thermal performance than standard double glazing, but that does not automatically make it the best choice for every home.

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The decision should consider:

• the existing construction

• the orientation of the windows

• the amount of glazing

• the level of insulation elsewhere

• noise requirements

• frame performance

• installation quality

• solar gain

• cost

• how long you expect to remain in the property

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In a highly insulated home, triple glazing may form part of a wider high-performance strategy.

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In another property, spending the additional money on wall or roof insulation may provide greater overall benefit.

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The Frame Matters Too

 

The glass is only part of the window.

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The thermal performance of the frame, seals, spacers and installation details also matter.

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Poor installation can create:

• draughts

• cold bridges

• condensation

• water penetration

• gaps around the frame

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A good-quality window badly installed can therefore perform far below its potential.

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Should You Replace Windows in a Victorian or Period Home?

 

Period properties require particular consideration.

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Original sash windows and other traditional joinery often form an important part of the character of the building.

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Complete replacement is not always the only option.

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Depending on the condition of the windows, alternatives may include:

• draught proofing

• repair and overhaul

• secondary glazing

• slim-profile glazing

• selective replacement

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In some properties, improving the existing windows may retain more of the character while still producing worthwhile comfort improvements.

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Planning restrictions, conservation-area requirements or listed-building considerations may also affect what can be changed.

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What About Secondary Glazing?

 

Secondary glazing involves installing an additional pane or glazed unit behind the existing window.

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It can be particularly useful in older or period homes where retaining the original external windows is desirable.

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Potential advantages include:

• reduced heat loss

• improved draught control

• significant noise reduction

• preservation of original windows

• less external alteration

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It may not provide the same appearance or convenience as completely new windows, but in the right property it can be a very sensible solution.

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Will New Windows Improve My EPC Rating?

 

Improved glazing can contribute to better energy performance, particularly where inefficient single glazing is being replaced.

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However, windows are only one part of the EPC calculation.

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The property may also benefit from improvements to:

• loft insulation

• wall insulation

• floor insulation

• heating

• hot water

• controls

• renewable energy

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That means spending a large sum on new windows may not necessarily be the most cost-effective way to achieve the EPC improvement you want.

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Could Insulation Give Better Value?

 

Quite possibly.

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If a property has reasonable double glazing but very little loft or wall insulation, improving the building fabric elsewhere may provide a larger reduction in heat loss for considerably less money.

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Likewise, improving heating controls or replacing an inefficient heating system may sometimes offer greater benefit.

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This does not mean replacement windows are a bad investment.

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It means they should be compared with the other opportunities within the property before a major order is placed.

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Windows Can Affect Summer Comfort Too

 

Glazing is not only about keeping heat inside during winter.

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Large areas of glass can also contribute to overheating during summer.

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South- and west-facing windows may allow substantial solar heat into a property.

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Depending on the home, summer comfort may be improved through:

• appropriate glazing specification

• external shading

• awnings

• blinds

• improved ventilation

• solar-control glass

• air conditioning or cooling

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This is another reason to consider windows as part of the whole-home strategy rather than simply selecting the lowest U-value available.

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New Windows and Ventilation

 

Older windows often allow a degree of uncontrolled air leakage.

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Replacing them with well-sealed modern windows can make the property significantly more airtight.

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That is generally beneficial for energy efficiency, but adequate ventilation still needs to be maintained.

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Bathrooms, kitchens and other moisture-producing areas require effective extraction, and more extensive energy improvements may justify reviewing the overall ventilation strategy.

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A warmer, more airtight home should also remain a healthy home.

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Do Not Let the Window Quote Decide the Strategy

 

A window installer can tell you about the windows they supply.

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But they are unlikely to assess whether your money would be better spent first on:

• wall insulation

• loft insulation

• heating

• ventilation

• solar panels

• a heat pump

• another energy improvement

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APN Green Homes takes a different approach.

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We do not start with the windows. We start with the property.

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Our aim is to help you understand where replacement glazing sits within your wider improvement plan.

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Grants and Financial Support

 

Financial support for home energy improvements changes over time, and eligibility varies between schemes and properties.

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Not every form of window replacement attracts grant support, so it is important not to assume funding will be available simply because the work improves energy performance.

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However, other improvements identified as part of the same whole-home assessment may qualify for grants, incentives or other financial assistance.

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As part of your Green Home Assessment, APN Green Homes considers the current support relevant to the improvements recommended for your property.

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That can help you decide whether the money you intended to spend on windows might be better combined with, or redirected towards, other improvements.

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Find Out Before You Spend

 

Before placing an order for replacement windows, it is worth asking:

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• Are my existing windows actually performing badly?

• Would double or triple glazing be more appropriate?

• Could secondary glazing be a better option?

• Would insulation provide a greater benefit for the money?

• How will new windows affect ventilation?

• Could different glazing improve summer comfort?

• Will new windows significantly improve my EPC?

• Are there other improvements I should carry out first?

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Get Independent Whole-Home Advice

 

APN Green Homes provides independent Green Home Assessments for homeowners considering significant energy improvements.

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Your personalised report can consider:

• windows and glazing

• draughts and air leakage

• roof and loft insulation

• wall and floor insulation

• heating

• ventilation

• summer overheating

• heat pumps

• solar and battery storage

• grants and incentives

• priorities for future improvements

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The aim is simple:

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To help you understand whether replacement windows are the right investment, what specification may be appropriate, and whether your money could achieve more elsewhere in the home.

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Green Home Assessment — £495 + VAT

 

Get the plan before you start spending.