Home Insulation: Your ultimate guide to a sustainable and energy-efficient home

When it comes to sustainable practices, the biggest obstacle for most people is not knowing where to begin. But we should remember that every action and choice in our daily lives has a direct impact on the quality of life and the overall environment. The first step to reducing your carbon footprint is an energy-efficient home; as we say, sustainability begins at our home! The best solution for an energy-efficient home is to have an efficient insulation system, and through this blog, we aim to answer all your questions related to sustainable home insulation.

Challenges of the UK Housing Stock

The UK has the oldest housing stock in Europe, with draughts and leaks across many of the currently existing structures. Draughts contribute to colder homes during winters, making heating expensive and difficult. During winters, humidity or temperature differences lead to condensation, and moisture absorption and cause damp patches and difficulty in keeping the property warm. 

Similarly, summers bring rising temperatures and heat waves, with draughts allowing heat to enter without restriction, causing excessive heat gain within the structure. These extreme conditions make homes ill-equipped for both seasons, leaving many homes unprepared for local and global climate changes due to poor maintenance and insufficient energy efficiency.

Taking such situations into account, it is more important now than ever to get your property inspected to determine what modifications can be made to reduce your energy bills and subsequent emissions. 

To cope with the demands of varying climates, investing in proper insulation becomes a major step toward achieving energy efficiency. 

What is Insulation?

Insulation is the process of creating a thermal barrier within a structure to slow down heat transfer between surfaces, ensuring the house remains warm in winter and cool in summer. It is mainly installed in areas like attics, walls, floors, roofs, windows, and doors.

There are three primary types of heat loss that occur within a structure daily, such as conduction, convection, and radiation. 

Conduction heat transfer occurs when the molecules in one part of the substance move faster as they heat up. Then they transfer this heat energy to molecules close by and so on down the line. Some materials conduct heat well, like stone, and other materials such as insulations are poor conductors.


Convection heat transfer takes place through the movement of liquids or gases. Convection is one of the reasons why your house cools down quickly when it’s windy – heat is blown away from your house more rapidly in a wind. One way to help insulate against convection heat loss is to ensure your house is well sealed.


Radiation heat transfer works without the need for direct contact or the air being blown around from the heat source. It does this through electromagnetic waves (infrared light) which are invisible to the human eye. This is the reason why things like black tarmac get hot on a sunny day as they slowly absorb the heat from the sun. The best way to reduce this form of heat transfer is to use low-emissivity surfaces such as that found in multi-foil insulations.

Although heat loss within a structure cannot be eliminated, a thermal barrier used between the surfaces can reduce the different types of heat transfer to a great extent! For the most effective thermal insulation, the chosen insulation material should address all three forms of heat transfer, regardless of the external weather conditions, to maintain a comfortable temperature across the structure.

To better understand the impact of thermal insulation, let’s observe how conduction, convection, and radiation heat loss operate between two surfaces in an uninsulated and insulated structure.

Uninsulated structure

Heat loss within a building happens every day, but during winter months or in other colder environmental conditions, this heat loss escalates. For an uninsulated property, there are no thermal barriers between the exposed external and unexposed internal surfaces. 

During summer, when heat comes in contact with the exposed surface, it is transferred to the adjacent unexposed surface easily through conduction, convection, and radiation, causing excessive heat gain and an uncomfortable temperature. 

Now if we consider this rate of heat loss within an uninsulated home, through multiple surfaces such as attics, roofs, walls, etc, it means the interior temperature can be really hot during summer and excessively cold during winter months. 

Insulated structure

Contrary to popular belief, insulation offers its benefits not just in winter but all year round! In terms of insulation materials with reflective properties, most of the radiant heat from the sun or any other source is reflected, preventing heat from entering or leaving the house. On top of that, the insulating material’s core component will make it difficult for any remaining heat (after reflection) to pass through or flow between the surfaces to limit conductive and convective heat transfer. 

In short, during winter, insulation helps prevent heat loss, making the house more comfortable while reducing the likelihood of moisture penetration, condensation, and any other associated problems from colder weather conditions. Also in the summer, insulation helps prevent hot air and dust from entering the house; keeping the home cooler and more comfortable. 

Why insulate?

1. Energy efficiency & lower bills

Keeping an uninsulated house warm isn’t easy. In the UK, about 60% of household energy usage goes towards heating. Without insulation, heat can escape or enter the building envelope, causing the heating and cooling systems consuming more energy to maintain a comfortable home temperature. This means, reducing the amount of heat lost from your home has a huge impact on lowering your energy bills.

The energy price cap per year for an average household increased to 54% in April 2022 and it was later replaced with a new Energy Price Guarantee in September, capping rates for the average household at £2,500 per year from October 2022, through April 30, 2023. Therefore, the amount that households can be charged per unit of gas, electricity and standing charges is restricted by the Energy Price Guarantee. These expenses will be higher if the household consumes more energy than the average limit and the lower bills are achieved only as a result of any energy conservation initiatives adopted! This means, the best way to achieve energy efficiency,  lower energy bills and an Energy Performance Certificate (EPC) for your home is by reducing the dependence on heating or cooling systems and investing in a long-lasting home insulation system. 

2. Damp and mould proofing

Condensation is less likely to build up on a warm surface! But a lack of insulation can cause obvious temperature differences between the inside and the outside building structure, such as walls, floors, ceilings and other sections. This temperature difference soon enough leads to condensation and the warm and humid air molecules touch the colder surface of the property,  it risks exposure to mould and other growth in the house! 

It is important to address any sources of moisture or dampness in the house promptly because when mould spores encounter a suitable environment with moisture, they can begin to grow and colonise in the affected area and typically growth begins within 24-48 hours of exposure to moisture. 

When insulation offers the house a better chance at fighting the mould by offering protection through a moisture control layer, vapour barrier, air sealing, and consistent thermal comfort, an uninsulated home is prone to draughts, and leaks. Therefore, an uninsulated house is more susceptible to moisture problems than an insulated home. 

While the wet and cold climate of the country, building fabric, and certain indoor activities are all major culprits in promoting such conditions, it is to remember that a lack of insulation is the primary reason in most cases. 

3. Carbon emission

“While nine in ten households rely on gas boilers to meet the household energy demands, the amount of fossil burned to meet these requirements equates to twice the EU average due to the poor housing stock.” 

The country is actively taking steps to achieve the 2050 Net Zero goal, and a ‘fabric first’ approach is becoming popular in this effort. The primary focus of a ‘fabric first’ approach is to make buildings perform better using eco-friendly and low carbon methods before relying on fossil fuels, mechanical or electrical systems and any other high carbon embodied solutions. This approach starts with prioritising insulation, retrofitting, draught-proofing, repairs, and ventilation ahead of any other add-ons.

Around  22% of the total carbon emissions result from domestic energy usage! Additionally, homes that are not energy-efficient tend to have higher consumption levels, followed by a massive release of carbon into the environment. Therefore, relying on the benefits of sustainable and cost-effective solutions, over gas, electricity, oil, etc becomes a priority decision and a straightforward solution for every household in an effort to reduce their carbon footprint.

Overall, insulation can significantly reduce greenhouse gas emissions not just by minimising the energy demand for the building, but also by bringing down the carbon footprint associated with the manufacture, transportation, and installation of heating/cooling systems along with the per capita emissions.

4. Elevating your home’s market value 

Insulation can significantly increase the home’s value in the real estate market for several compelling reasons. First, a fully insulated home requires very little additional heating and cooling and can improve your EPC rating (Energy Performance Certificate), which makes it attractive to buyers seeking energy efficiency and cost savings. 

While ensuring consistent indoor temperatures year-round, insulation also enhances comfort, reduces utility bills, and contributes to a healthier living environment by preventing issues like mould growth and dampness, which can affect the overall indoor air quality.

An insulated home also aligns with the sustainability initiatives that are currently gaining momentum, making it appealing to environmentally conscious buyers. As energy efficiency regulations evolve and buyers prioritise eco-friendly and low-operational cost features, it also showcases the property as a wise long-term investment. 

On top of that, an insulated home requires fewer maintenance expenses and offers a marketing edge, setting it apart in a competitive market. These advantages can positively influence property appraisals and valuations, making your home a more appealing choice for potential buyers. 

Where should I insulate? 

The primary areas that require insulation in buildings are attics, roofs, walls, floors, windows, and doors. 

Lofts & Roofs: around 25% of heat escapes through the roofs or attics of an uninsulated home. One of the main considerations while insulating a roof will be if the attic/roof space is to be used as a living space or for any other purposes, as this will determine if insulation should be at ceiling level or on the roof pitch itself. Things like re-roofing a property are also great opportunities to add insulation with minimal disruption and additional cost.

Walls: Poor wall insulation accounts for about 35-45% of the overall heat loss within a home. Since there are solid walls and cavity walls, the wall type must be taken into account before insulating your property. The reason is that while both wall types can be insulated externally and/or internally, insulation choices and techniques vary across both types. The choice often depends on the property size, budget, insulation space, convenience etc.

Floors: Floor insulation has a great impact on energy efficiency. A properly insulated suspended timber or concrete floor saves above 10% of the overall heat loss that occurs via floors in a regular dwelling.

Doors & windows: Windows and doors are often the weakest points in a home’s insulation. About 15% of heat loss occurs via doors and 10% via windows in most scenarios. Cutting out drafts and cold spots prevent heat loss from happening through conduction and radiation to a great extent while draught-proofing doors can save up to £60. Replacing single-glazing window panes with A++ certified double-glazing helps save up to £235 annually and 405 kg of carbon dioxide emission for an average household! 

Pipes & ducts: Insulating pipes and ducts can prevent heat loss and reduce energy bills. This is especially important in areas of the home where pipes and ducts are located in unheated spaces, such as the basement or attic.

Can I insulate an old house?

Insulation is equally essential for new builds and retrofits for achieving optimal energy efficiency and is often installed from the roof to the foundation. But many older homes have less to no insulation than homes built today. Therefore, when it comes to installing thermal insulation, there is an evident confusion holding back the old housing stock owners.

Improving insulation might seem difficult, expensive, and disruptive, especially if it requires changing/modifying parts of the building to address energy compromised areas. This is the reason why one of the most often consulted questions before insulating or renovating such properties is ‘Is it worth it?’ 

The answer is Yes! ‘Older buildings’ are leaky, and making them airtight by sealing gaps, cracks and draughts has its range of benefits!

The cost of insulating an old house can indeed be slightly higher than that of a new one. While you think the heat loss that may occur through such draughts, damp and exposed building sections could be relatively small, a prolonged period of heat loss might have a significant impact on the building’s overall energy consumption and energy retention capabilities. Additionally, shifting pressure across the structure, seasonal changes, and extreme weather conditions can all worsen the building’s thermal envelope over time. 

Since the initial investment in insulation can be recovered in the following years through lower spending on the overall energy bills, improving your home’s insulation is a great way to help keep your monthly outgoings down and reduce your home’s carbon footprint. 

How to begin?

Home insulation varies from quick fixes to professional installations. Deciding what works best for your project depends on your insulation goals, building control and regulations, home location, budget, etc. Knowing the U-value you’re looking to achieve is a key step toward selecting the perfect insulation for your project. U-value refers to the thermal performance of a structure, and this value decides the thermal resistance (R-value) the insulation material should have. If your property has a higher U-value, you will be spending more money than necessary trying to keep your home warm! 

Proper installation is yet another potential factor to lookout for while insulting your home. To maximise the benefits of insulation, including energy efficiency, comfort, and indoor environmental quality, proper insulation installation is significant, it is essential to ensure that your insulation is installed properly. 

Following installation guidelines, building codes and using appropriate tools and materials are all part of proper installation techniques and if you are not a trained installer or are unsure about anything, we always recommend hiring qualified professionals to meet your project needs. 


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