Why Is Home Insulation Important?

 

Heat naturally moves from warmer areas to colder areas.

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During winter, heat generated inside your home can escape through the roof, walls, floors, windows and uncontrolled gaps in the building.

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Insulation slows this transfer of heat.

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A better-insulated property may therefore:

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• require less energy for heating;

• remain warmer for longer;

• have more consistent internal temperatures;

• reduce cold surfaces;

• improve comfort;

• help reduce household energy costs; and

• make low-temperature heating systems more practical.

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Insulation can also influence the size and performance of future heating equipment.

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House Insulation

 

The term house insulation covers several different parts of the building.

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Depending on the construction, opportunities may include:

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• loft insulation;

• attic insulation;

• pitched roof insulation;

• flat roof insulation;

• cavity wall insulation;

• internal wall insulation;

• external wall insulation;

• suspended floor insulation;

• solid floor insulation; and

• insulation incorporated into extensions or refurbishment work.

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The appropriate solution should be based on the construction of the property rather than applying the same system to every home.

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Loft and Attic Insulation

 

Loft insulation is often one of the first areas worth investigating because warm air rises and significant heat can be lost through an inadequately insulated roof.

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In a traditional house with an unused cold loft, insulation is commonly installed at ceiling level between and over the ceiling joists.

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Where the roof space is used as accommodation, the insulation strategy will normally be different and may involve insulating the roof slopes.

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Homeowners searching for attic insulation are generally considering the same part of the building, although in the UK the term loft insulation is more commonly used.

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How Much Loft Insulation Do You Need?

 

The appropriate thickness will depend on the type of insulation material, existing construction and current standards.

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Simply adding another layer without inspecting what is already present is not always the best approach.

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Existing insulation may be:

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• compressed;

• uneven;

• missing in areas;

• disturbed by storage;

• affected by moisture;

• badly installed around services; or

• blocking required ventilation.

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The loft should therefore be considered as a complete roof-space system.

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Attic Insulation Cost

 

The cost of attic or loft insulation will depend on the size and accessibility of the roof space and the work required.

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Factors affecting price can include:

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• floor area;

• existing insulation;

• insulation material;

• required thickness;

• access;

• stored belongings;

• boarding;

• water tanks;

• electrical cables;

• pipework;

• ventilation requirements; and

• whether existing defective insulation needs to be removed.

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A simple open loft can be relatively straightforward, while a heavily boarded or difficult-to-access roof space may require considerably more work.

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External Wall Insulation

 

External wall insulation involves applying insulation to the outside face of the building and covering it with a protective finished layer.

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It can be particularly relevant to solid-wall properties that do not have a cavity suitable for conventional cavity-wall insulation.

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Potential benefits can include:

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• reduced wall heat loss;

• improved internal surface temperatures;

• reduced cold bridging;

• improved weather protection; and

• the opportunity to refresh the external appearance of the building.

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However, it represents a substantial alteration to the property and needs to be properly designed.

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Is External Wall Insulation Suitable for Every House?

 

No.

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Suitability can depend on:

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• wall construction;

• architectural character;

• roof overhangs;

• window and door details;

• damp conditions;

• gutters and downpipes;

• external services;

• boundaries;

• adjoining properties; and

• planning restrictions.

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The work changes the thickness and appearance of external walls, so junctions around roofs, windows, doors and ground level all require careful consideration.

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Historic and traditionally constructed buildings may require a different approach.

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External Wall Insulation and Planning Permission

 

External wall insulation can materially alter the appearance of a property.

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Planning considerations may therefore arise, particularly for:

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• listed buildings;

• conservation areas;

• terraced properties;

• houses with distinctive architectural detailing;

• properties close to boundaries; and

• homes subject to other planning restrictions.

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Where the external appearance will change significantly, it is sensible to establish the planning position before committing to the work.

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Cavity Wall Insulation

 

Many homes built with cavity walls may already have insulation within the wall cavity or may potentially be suitable for cavity-wall insulation.

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However, not every cavity should automatically be filled.

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Factors such as exposure, cavity condition, wall construction, moisture and previous alterations need to be considered.

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If there are concerns about damp or existing defective cavity insulation, specialist investigation may be required before further work is undertaken.

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Internal Wall Insulation

 

Internal wall insulation involves adding insulation to the inside face of external walls.

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This can sometimes provide an alternative where external wall insulation is unsuitable or where the appearance of the outside of the building needs to remain unchanged.

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However, it reduces internal room dimensions and affects:

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• skirting boards;

• sockets;

• radiators;

• window reveals;

• decorative finishes; and

• junctions with floors and ceilings.

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Moisture movement and condensation risk also need to be considered carefully.

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Floor Insulation

 

Heat can also be lost through ground floors.

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The appropriate insulation method depends on whether the property has a suspended timber floor or a solid floor.

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Suspended floors may sometimes be insulated between the timber joists while maintaining necessary sub-floor ventilation.

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Solid floors are more likely to be upgraded when major refurbishment or floor replacement is already planned.

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Floor insulation can be particularly worthwhile where rooms feel cold at low level or substantial renovation work is taking place.

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Insulation During an Extension or Renovation

 

Major building work provides an excellent opportunity to improve insulation.

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If walls, floors, roofs and ceilings are already being opened or reconstructed, additional insulation can often be incorporated more easily than it could be afterwards.

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An extension or refurbishment may provide opportunities to:

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• improve existing loft insulation;

• upgrade roof insulation;

• insulate suspended floors;

• improve external walls;

• replace glazing;

• reduce draughts;

• improve airtightness; and

• prepare the property for a heat pump.

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It is therefore worth looking beyond the new extension itself and considering whether adjoining parts of the existing house should also be improved.

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Insulation and Heat Pumps

 

Insulation becomes particularly important when a homeowner is considering an air source heat pump.

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A heat pump can work effectively in many types of property, but reducing unnecessary heat loss may allow the heating system to operate at lower temperatures and potentially improve overall performance.

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Before changing the heating system, it can therefore be sensible to assess:

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• roof insulation;

• wall insulation;

• floor insulation;

• glazing;

• draughts; and

• the general heat-loss characteristics of the property.

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The objective is not necessarily to achieve a perfect building before installing a heat pump, but to understand whether sensible fabric improvements should be made first.

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Insulation and Solar Panels

 

Solar panels and insulation solve different problems.

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Solar PV helps generate electricity.

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Insulation helps reduce the amount of energy the property needs.

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The two can therefore complement one another.

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A home that requires less energy and generates more of its own electricity can move towards lower running costs from both directions.

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This is why a Green Home Survey considers both energy demand and energy generation.

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Insulation and Windows

 

Replacing windows can improve comfort and reduce draughts, but glazing should be considered alongside the surrounding walls and roof.

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There may be limited value in installing very high-performance windows while leaving substantial areas of poorly insulated building fabric untouched.

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Similarly, insulation work around windows needs to consider reveals, lintels and other junctions where thermal bridging can occur.

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A whole-home approach can help identify where improvements are likely to have the greatest effect.

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Insulation and Ventilation

 

Insulation should not be considered without ventilation.

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As properties become better insulated and more airtight, uncontrolled draughts reduce.

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This is generally beneficial for energy efficiency, but the home still needs sufficient fresh air and moisture removal.

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Poor ventilation can contribute to:

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• condensation;

• mould;

• high humidity;

• stale air; and

• poor indoor air quality.

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Depending on the property, ventilation may involve background ventilation, extract fans, continuous mechanical ventilation or MVHR.

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A greener home should be both energy efficient and healthy to live in.

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Draught Proofing

 

Not all heat loss requires major insulation work.

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Uncontrolled air leakage around doors, windows, floors, loft hatches and other openings can make a property uncomfortable and increase heating demand.

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Suitable draught-proofing can sometimes provide a relatively low-cost improvement.

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However, intentional ventilation openings should not simply be sealed.

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The aim is to reduce uncontrolled air leakage while maintaining adequate designed ventilation.

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Insulation for Older and Period Homes

 

Older properties require particular care.

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Traditional solid-wall buildings may behave differently from modern cavity-wall construction and may rely on materials that allow moisture to move through the building fabric.

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Using inappropriate insulation materials or preventing walls from drying properly can potentially create damp and deterioration.

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Before undertaking major insulation work to an older property, it is important to understand:

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• wall construction;

• existing materials;

• moisture conditions;

• ventilation;

• previous alterations; and

• the architectural character of the building.

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The solution appropriate for a modern house may not be appropriate for a Victorian or Georgian property.

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Insulation in Listed Buildings and Conservation Areas

 

Listed and historic buildings can often be improved, but interventions need to respect the significance and traditional construction of the property.

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External wall insulation may not be acceptable where it changes important architectural details.

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Internal insulation may also require careful design to prevent damage to historic fabric or moisture problems.

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Listed-building consent or planning permission may be required for certain alterations.

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Improving an older home is therefore often about finding the correct balance between energy efficiency and conservation.

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Home Insulation Cost

 

The cost of home insulation varies enormously because different parts of a property require very different work.

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A straightforward loft insulation project may represent a relatively modest investment.

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External wall insulation, major roof upgrades or whole-house internal insulation can be substantial projects.

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Cost can depend on:

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• area being insulated;

• insulation type;

• accessibility;

• preparation work;

• scaffolding;

• finishes;

• building condition;

• associated repairs;

• planning requirements; and

• whether the work forms part of a larger renovation.

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Comparing cost alone is rarely sufficient. The likely energy benefit, disruption and lifespan of the work should also be considered.

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Free Loft Insulation and Insulation Grants

 

Homeowners frequently search for free loft insulation and other forms of financial support.

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Government, local-authority and energy-company schemes may provide assistance towards qualifying energy-efficiency improvements, including insulation.

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However, schemes, funding levels and eligibility requirements change over time.

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Whether assistance is available may depend on factors such as:

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• household circumstances;

• income;

• benefits;

• Council Tax band;

• property energy performance;

• heating system; and

• local funding programmes.

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It is therefore worth checking current grant and funding options before commissioning significant insulation work.

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Choosing Insulation Installers

 

The quality of installation can be just as important as the insulation material itself.

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Poor workmanship can create gaps, thermal bridges, blocked ventilation or moisture problems.

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When comparing insulation installers, homeowners should consider:

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• experience with the relevant building type;

• proposed insulation system;

• technical details;

• ventilation strategy;

• guarantees;

• accreditation where appropriate;

• preparation work;

• finishes; and

• how junctions and difficult areas will be treated.

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The cheapest quotation may not represent the best long-term value.

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Where Should You Start With Home Insulation?

 

The answer depends on the property.

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For some houses, loft insulation provides the obvious first improvement.

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For others, external or internal wall insulation may offer greater potential.

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A house undergoing extensive renovation may justify a much more comprehensive approach involving the roof, walls, floors, glazing and ventilation at the same time.

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The important thing is to understand where the home is losing energy before deciding where to spend the money.

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Home Insulation as Part of a Green Home Plan

 

Insulation can affect almost every other major home energy decision.

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Better insulation reduces heat demand.

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Improved glazing can increase comfort and reduce draughts.

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A heat pump may operate more effectively in a lower heat-loss property.

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Solar panels can generate electricity.

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Battery storage can help manage electricity use.

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MVHR can provide controlled ventilation while recovering heat.

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The best results can come from considering these measures together rather than treating insulation as a completely separate project.

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Independent Home Insulation Advice

 

Insulation installers naturally concentrate on the systems they supply.

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APN Green Homes takes a wider approach.

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A Green Home Survey can consider where insulation improvements may be worthwhile, whether they should take priority over other technologies and how the building fabric affects heating, ventilation, solar generation and future energy plans.

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The aim is to identify what your particular home needs before committing to major expenditure.

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Start With the Building Fabric

 

There is little point generating or purchasing energy unnecessarily if much of it is immediately being lost through the building.

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Understanding the roof, walls, floors, windows and ventilation can therefore provide the foundation for a much more effective green home strategy.

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NEXT STEPS

Every home is different, so the right next step depends on your property, your budget and what you want to achieve. APN Green Homes can help you turn the information you have just read into a practical plan for your own home. Whether you are considering one improvement or looking at a complete whole-home energy upgrade, we can help you understand what is suitable, what should be prioritised and where your money is likely to make the greatest difference.

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Choose one of the options below to get the ball rolling:

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BOOK A GREEN HOME SURVEY
Get a detailed assessment of your home with practical, property-specific recommendations and a clear plan for the improvements worth considering.

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BOOK A PHONE CONSULTATION
Talk through your property, ideas and priorities with us and get some initial direction on the best way forward.

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EMAIL US
Send us details of your property, photographs or any questions and we can advise you on the most appropriate next step.

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GIVE US A CALL
Prefer to speak to someone? Give us a call and tell us what you are hoping to achieve.

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Your greener, more efficient home starts with understanding the right improvements for your property — and putting them in the right order.