How to Make a House Energy Efficient

Being energy efficient and reducing our consumption of energy in the UK contributes to meeting our commitments pledged to tackle climate change.

As 22% of our carbon emissions currently come from our homes, there is an urgent need to drastically reduce household energy bills and increase energy efficiency. The government wants all housing to be rated C or higher, currently, only 40% of UK housing has an EPC rating of C or above. We have a long way to go.

In the UK we are now experiencing significantly higher energy costs than we have known in years, leaving many households wondering how they will continue to afford to heat their homes.

So, how do we make a house more energy efficient?

How Energy Efficient Is Your Home?

Before you start making any changes to your property, first of all, review how energy efficient your house currently is. The easiest way to do this is by looking at your Energy Performance Certificate (EPC).

If you bought your house after 2007, you will have received a certificate that shows the energy consumption of your home.

If you don't have a certificate you can contact a qualified EPC surveyor who can conduct a survey for you at a cost between £50-100.

There are three areas that the EPC is assessed:

• Heating
• Lighting
• Hot water

All the appliances used for heating, lighting and hot water are considered and the energy consumption is calculated on the amount of energy used per m2 and the level of CO2 emissions (given in tonnes per year).

One of the more useful parts of the EPC is the recommendations that tell you how you can improve your EPC rating by reducing your energy consumption to make your home more energy efficient.

Read more: Energy Performance Certificates...

How to Make Your Home More Energy Efficient

To make your home more energy efficient, there are five key areas to review and improve:

• Insulation
• Draught proofing
• Light
• Heat
• Hot water

If you don't have an EPC (as mentioned above), you can make an assessment of your house by reviewing these five main areas and following the recommendations below.

When considering what to do first to make your home more energy efficient, consider that a leaking bucket will keep losing water however much you keep pouring in.

Therefore, tackling insulation in your home should be a priority to make sure that as much heating as possible is kept in the house and you are not paying to see your heat go through the roof (so to speak).

Insulation

Wall Insulation

A third of the heat from a house can be lost through the walls if they are not insulated. Terraced houses or apartment blocks are the most efficient as they benefit from being insulated by their neighbours. Detached houses are the most inefficient as they have four walls and a roof exposed.

Most houses built after 1990 will have insulated walls and do not need extra insulation. Houses built between 1920 and 1990 will usually have cavity walls and houses built before 1920 will usually have solid walls.

Cavity wall insulation is relatively easy to install but there is an important caveat that with houses exposed to excessive wind and rain, it might be unsuitable. Insulation that suffers water ingress will develop dampness and mould and this can be a significant health problem. Make sure to take advice from a qualified and reputable installer as a bad installation can be costly to rectify.

For solid walls that don't have a cavity, the external walls can be clad and/or internal walls clad with insulating material. This is a more intrusive and costly investment than cavity wall insulation.

Cavity wall insulation can save up to £235 annually for a semi-detached house. Solid wall insulation can save up to £315 annually for a semi-detached house.

Floor Insulation

Draughts from floors or cold floors can not only reduce the temperature of a room, but they will also make you feel more cold. By insulating floors, it will make you feel warmer and help with warmth retention in the room.

Upper floors don't usually need floor insulation as they will benefit from heat from the room below unless they are built over a void. Insulation only needs to be applied to the ground floors.

Older houses can have suspended floors and floorboards and often have gaps and plenty of draughts. As a starting point, try to seal gaps where you can and use rugs to keep floors feeling warmer.

Suspended floors can be insulated with rock wool between the underside of floorboards held in place with netting.

Newer homes will have concrete floors and these can be insulated with solid insulation boards laid on the floor and under flooring.

Suspended floor insulation can save £70 a year for a semi-detached house.

Loft Insulation

Heat rises and in a house, a quarter of heat is lost through the roof. One of the easiest and most effective ways to make a house more energy efficient is by installing loft insulation.

The recommended depth of rock wool is 270mm.

For a house that doesn't have insulation and installs 270mm of rock wool the energy saving can be a big saving of £225 annually for a semi-detached house.

Roof Insulation

As an alternative to loft insulation, or for converted loft spaces, the underside of the roof can be clad internally with insulation boards. Any gable walls will also need to be clad and insulated to be effective.

Hot-water Cylinder Insulation

Adding insulation to a hot water tank and water pipes is a quick and easy job that anyone can do. A cylinder jacket will retain heat so that it takes your tank less time to heat water each time and saves energy use. The minimum thickness of insulation should be 80mm.

Lagging pipes will not only insulate the hot water but also protect them from cold and the disruption of burst frozen pipes. Foam tubes can be bought from any DIY store and fitted quickly and easily.

Insulating an old uninsulated hot water cylinder with a minimum of 80mm could save you £180 a year. Increasing insulation from 25-80mm will save £45 a year.

Energy Efficient Windows with Low U-value

Energy efficient windows are constructed so they reduce as much heat loss as possible. The glass, the frame and the construction all contribute to how efficient the window is.

U-values measure the energy transfer through solid materials and the lower the U-value the more energy efficient the window is.

Choosing windows based on a low U-value of 1.4 or less will mean less heat loss from a room and less energy use and saving money on energy bills.

Everest Ultimate Double Glazing has a U-value of 1.22 and Everest Ultimate Triple Glazing has a U-value of 0.8.

Note that for replacement windows in an existing building, Building Regulations require a U-value of 1.4 or less.

Replacing single glazing with triple glazing can save up to £915 a year on energy costs. Replacing old double glazing to triple glazing can save up to £365 a year on energy costs - read more about energy efficient windows.

Energy Efficient Doors

Like windows, doors allow heat to escape and if they are not fitted snugly in a frame can have significant drafts around the edges.

An energy-efficient doorset will have an integrated draught proof frame, letter box and glazing. The door slab will also be insulated for minimum heat transfer.

Building Regulations require a door in an existing dwelling to have a U-value of 1.4 or lower.

Draught proofing windows and doors can save £35 a year.

Double Glazing →

Our double-glazed windows have energy ratings up to A+ and U-values as low as 1.20.

Triple Glazing →

Our triple-glazed windows are our most energy-efficient, with energy ratings up to A++ and U-values as low as 0.80.

Draught Proofing

Draught Proof Gaps

Older houses were built to have much more ventilation than modern builds. Because Victorian houses relied on coal fires, ventilation was essential to circulate the heat and maintain a healthy balance of oxygen in the room. New builds are much more insulated and required to be airtight under Building Regulations.

For existing buildings, when doing any renovation work care should be taken to reduce unwanted heat loss through air infiltration (draughts) by sealing around any service pipework and making sure windows and doors are well fitted.

To help draught-proof your home:

• Periodically adjust the hinges on a uPVC door to ensure a tight fit
• For older doors, apply insulation strips around the inside frame
• On windows, fill any gaps around the frame with caulk or silicone
• Use a chimney pillow/draught excluder to block chimneys not in use

Draught proofing doors, windows and gaps can save £35 a year.

Fit Shutters and Heavy Curtains

Old fashioned techniques such as fitting shutters and heavy drapes to windows make a considerable difference to keep cold out and warmth in a room. They work.

Closing curtains and shutters as soon as the sun goes down will help to retain the heat in the room.

Always open the curtains or shutters as soon as it gets light to take advantage of any solar gain to warm the room for free.

Light

Install Energy Efficient Light Bulbs

The most basic energy-saving measure you can take in your house is to upgrade all incandescent bulbs to LED bulbs.

If everyone in the UK was to replace their old bulbs with LED, the UK would save 1.8 million tonnes of C02 a year.

Turn off Lights

It might seem obvious but turning off lights when you are not using a room, or are out of the house, will save energy. It also contributes to increasing your EPC rating.

Turn off Standby Appliances

Electrical appliances are energy hungry even when they are in standby mode.

Try this simple test, check your smart meter to see how much energy your home is currently using. Then turn off everything in the house except for your fridge freezer (or anything essential) and compare the difference.

Don't leave appliances on standby - turn them off.

Composite Doors →

Unglazed 70mm composite door – 0.98 W/m2K U-value & A++ energy rating

uPVC Doors →

Made-to-measure for a millimetre perfect fit – 1.41 W/m2K U-value & B energy rating

Timber Doors →

Naturally insulating solid hardwood exterior doors

Heating

Upgrade Your Boiler

Heating your home and hot water consumes over half of your energy bill spending, so any changes you can make in this area will have the most impact on your bills.

If you are spending money to heat water, then you want to retain the heat as long as possible. This starts with insulation (see above).

If you have an older boiler, upgrading to a new energy efficient model can see significant savings.

When researching a new boiler, also consider the size of your house, how many people use it and the output you require. A boiler that is just the right size for your needs will be more efficient than a boiler that is oversized or undersized.

Also note, with government proposals to phase out fossil fuels and a ban on gas boilers starting in new build houses from 2025, start to research other low carbon alternatives such as heat pumps.

Upgrading an old G-rated boiler to a new A+ rated energy efficient boiler can save up to £310 per year in a semi-detached house.

Fit Thermostats

Having thermostats fitted on all radiators in your home will give you full control of your heating system and allow you to optimise your system to be as efficient as possible. Setting radiators to a 'frost' setting in unused rooms will keep them from becoming a heat drain and keep them above freezing. Only heating the rooms you need, as you need them will cut your bills.

Limit How Often the Heating Is On

Instead of having the heating on through the night or all day, try reducing the time you switch on the heating. For example, only set the heating to turn on just before you get out of bed, and just before you come home. Turn the heating off before you go to bed so the house is cooling as you go to sleep.

Don't forget to reset your heating controls when you are on holiday or the house is unoccupied with a maintenance frost setting.

Turn the Thermostat Down

Instead of wearing a T-shirt indoors in the winter, put on a jumper and turn your thermostat down. Don't risk your health by turning the heating off, but do try to be more considerate with your usage – do you need the room to be as hot as it is?

Just turning it down by one degree can save 10% on your energy usage. If everyone in the UK dialed down by one degree, 3.5 million tonnes of C02 a year could be saved.

Hot Water

Reduce the Washing Machine Temperature

Modern washing machines are much more efficient than old versions, but the biggest saving you can make is by reducing the temperature down to 30 degrees. Also, be mindful of your usage and only run full loads rather than small loads on a frequent basis.

Don't Use a Tumble Dryer

Drying clothes with a tumble dryer racks up your energy bills when the same chore can be done for free.

Always dry clothes outside when the weather is fair, or use drying racks in the house. Old fashioned drying racks suspended from the ceiling work very well. If you do dry clothes indoors, don't forget to ventilate the room with a window on a vent latch or a trickle vent to avoid a build-up of condensation.

Not using a tumble drier can save £50 a year.

Use a Shower Timer and Reduce Baths

Heating hot water is costly so the less you need the more you can save. Use a shower timer to help you get used to shorter showers and wash more quickly. Also, avoid having baths as a quick shower will use far less hot water.

Reducing your shower time to four minutes can save £55 a year.

How Much Can an Energy-Efficient House Save on Energy Bills?

Data in table above uses April 2024 energy prices, quoted for an average three-bedroom semi-detached house and sourced from the Energy Saving Trust. ** Everest data.

Sources here and here, for all data and statistics quoted above.