The importance of insulated homes in reducing our demand for energy

Insulating our homes is important in order to slow down heat loss and reduce our consumption of gas and electricity.

Most Victorian homes are not insulated.  The ones that are insulated have been retrofitted with insulation by subsequent conscientious Owners.

How to Insulate Your Home


Cavity walls

Insulation is installed within the cavity of the wall and this is usually done during the original construction since cavity wall construction is a more modern method than what the Victorians and Edwardians used when building their houses and unfortunately, for reducing heat loss.  It is these types of houses that dominate London.

Solid Walls

Victorian and Edwardian houses were built using solid brick walls comprising either Flemish or English brick bonding which is an interlocking method of laying the bricks on top of each other. Typically walls are 225mm thick + plaster.

Internal Insulation

This is known as dry-lining and comprises laminated plasterboard which is fixed to the internal surface of the external walls.  This method is less popular because it is more disruptive.  The internal floor area will be reduced and all internal fixtures and fittings have to be removed prior to installation.

Applying insulation externally

Applying Insulation to the outside surface of the external walls is an effective way to improve the insulation without losing any internal floor area.

A laminated render board such as a product called KRend can be fixed to the outside of your external walls.  This render board is available in numerous finishes including render, brick and timber.  If the external finish does not match the existing finish it will need planning approval.


Most insulation is Rockwool and it is installed at ceiling level where the loft is converted into a habitable room.  Roof insulation is typically installed in-between the pitched rafters or within the flat roof of the dormer.  This type of insulation is important in retaining the warm air and bouncing it back into the rooms below. This is known as emissivity and is assessed when calculating the U value, or thermal transmittance of an element.  Headroom is typically an issue when converting lofts and therefore every millimetre has to be accounted for in maximising the ceiling height.  As such, it is not always possible to detail the insulation in the most effective way.  Most flat roof dormer insulation detailing positions the bottom of the insulation flush with the bottom of the joists with a thinner layer of insulation then fixed to the underside of the joists to prevent cold bridging.

However, if height is not limited, it is much better to position the insulation 25mm above the bottom of the joists.  This creates a small cavity in between the insulation and the top of the plasterboard which allows the warm air to be bounced back so you get more heat for your money.

Pitched roof insulation


Suspended timber floors

This is the least likely element to be upgraded yet has the most impact by reducing drafts and preventing warm air from being pushed out of your house.  Uninsulated floors will cost you a lot of money because the heating that you are paying for is being pushed out by the cold air coming through the floor via the sub-floor vents.  These vents are important in keeping your timber joists dry and so cannot be removed or blocked up.


Other floors types.

Ground bearing reinforced concrete slabs, concrete beam and block floors and hollow-core floor panels are more difficult to retrofit with thermal insulation.  The two methods are removal and installation of insulation below or above the floor.  The cost and reduction in ceiling height could be prohibitive.

Suspended Floor insulation

Windows and Doors

Windows and Doors are now available with a thermal insulated core as well as double/triple glazing with low ‘e’ glass.  This glazing slows down the transfer of warm air out of the glass and the low ‘e’ coating helps to bounce warm air back into your house. This is a method of retaining and recycling the warm air.

Low emmissivity glass

Clothing & Lifestyle

Wearing additional clothing inside our homes is the most straightforward method of keeping warm. There are warm and breathable fabrics available to make this a comfortable option, reducing our energy use and saving a lot of money in the process.

Adapting our lifestyles is another viable and effective option to reduce our energy use.  Over the previous 3-4 generations our demand for energy has increased massively.  Our thirst for energy continues to increase with exponential population increase, the popularity of the television,  our reliance on computers for work and entertainment and our increasing dependence on travel for commuting holidaying and shopping.

Any and all methods which help us to reduce our energy consumption has now become essential in reversing the damage to Earth.  So instead of watching TV or browsing our electronic devices, we should get outside and exercise, read books and magazines (not tablets), interact more and talk face-to-face in person.

As well as their environmental benefits these changes are very likely to lead to improved social lives and personal health both of which have been declining at a similar rate to the health of our planet.

Any activity which reduces our use of electricity, gas or fossil fuel is a responsible way to live.

All of these methods are important in reducing our consumption of energy which is a National and global problem adding to the heating up of our planet. Whilst these methods seem straight forward the insulation should be properly installed to allow for optimum performance of the insulation.  The key in detailing is to retain and recycle the warm air.

An important consideration of Good Practice detailing is to maintain adequate ventilation to prevent condensation and to protect the health of the building fabric as well as our own.

For more information, please contact GA Architects.

Sustainable happy families