An important consideration for any property owner these days is how to save energy. Increasing energy prices, concern over global warming and government energy efficiency targets are making reductions in energy bills and CO2 emissions a major concern for both owners and tenants in buildings of all sizes.

The biggest problem that most people face when they come to improve the energy efficiency of a building is the bewildering amount of options available to them. There are literally hundreds of products and methods for saving energy and reducing equivalent CO2 emissions. Given the large amount of options available to them, how should someone go about choosing the best way to save energy?

Costs Versus Savings

If your goal is to save money on bills by using less energy, and consequently outputting less equivalent CO2, some of the key things to look at in potential methods are the cost of purchase/installation and the amount of money potentially saved each month. If you divide the cost of purchase/installation by potential monthly savings, for a particular method or system, then you can work out what is called the ‘payback period’.

The payback period of any energy saving system is the amount of time it takes for that particular method to recover its purchase and installation cost through the savings made. Take the example of an energy efficient light bulb. If the light bulb costs £4 to buy and install and saves you £2 per month on your lighting bill, the payback period would be 2 months. Any money saved after that point becomes a direct saving to you.

The Biggest Target

For most people, their largest energy expenditure goes to their heating bill. Most energy saving products and systems are designed to reduce the amount of energy required to sufficiently heat a property. The most popular methods are:

  • Double Glazing – Double glazed windows are, on average, about 50% more efficient at stopping heat loss than windows with single glazing.
  • Insulation – There is a wide range of different insulation methods available to the householder, such as cavity wall insulation, roof/loft insulation and solid wall insulation. All of these reduce heat loss from the home.
  • Waterproof Coatings – Dry masonry and brickwork have far better insulating qualities than when they are wet. A coating of water repellent can keep masonry and brickwork dry.

With so many methods available it is logical to implement the methods with the shortest payback period first. There are also many other small things the homeowner can do to save money on their heating bills that have no significant outlay, such as lowering your thermostat by 1°C or installing heavier curtains.

Seeing Through Double Glazing

Double Glazing is commonly one of the first energy saving methods people implement. Whilst it is true that double glazed windows can be much more efficient at stopping heat loss than single glazed windows, they often have a small overall effect on the total heating bill. 

Given the average cost of £5000 for the purchase and installation of double glazed windows in a 3 bedroom house, the 10% energy bill savings made afterwards mean that the payback period is often very long. Using figures presented by the Energy Saving Trust, the best case scenario for double glazed windows in a gas heated house is a payback period of 28 to 50 years.

Most of the advantages of double glazed windows can be achieved by correctly draught proofing and secondary glazing any original window frames, at a fraction of the cost. As long as they are properly maintained, single glazed windows are not necessarily a large drain on heating bill costs.

A Better Solution

Insulation in combination with a waterproof coating, such as Stormdry, is a far more cost effective way of cutting heating bill costs, when compared to double glazing. A third of all heat in a property is lost through the walls, so it makes sense to insulate your walls before considering double glazed windows.

One of the most cost effective methods of wall insulation is cavity wall insulation. For a relatively small outlay it is possible to save an average of 20% on your energy bills. There are, however, drawbacks to this form of insulation. Cavity wall insulation is often installed without proper attention being paid to the porosity and condition of the wall itself.

If steps aren’t taken to ensure that rain water does not penetrate the bricks, there is a risk that cavity wall insulation will get wet. Once the insulation is wet, the majority of the thermal benefits it would normally provide will be lost.

A deeply penetrating, long lasting and effective water repellent, such as Stormdry, can protect cavity wall insulation and even enhance its performance for up to 30 years. When using Stormdry, it is important to make sure that any necessary masonry repairs are carried out on cracks or major defects. 

The Ideal Solution

The ability of a wall to insulate is determined by its thermal resistance. A wall with a high thermal resistance will lose less heat than a wall with low resistance. The thermal resistance of brickwork and masonry can be very dependent on how wet it is. Tests show that the thermal resistance of a Stormdry treated brick is over twice that of a wet brick. 

Depending on the weather, a wall treated with Stormdry alone has been proven to save between 7% and 27% on energy bills. On average, a Stormdry treatment on a 3 bedroom house will cost of £500 to apply and give a payback period of 6 years, making for a significantly better return of investment than that provided by double glazed windows.

If Stormdry was to be applied to a 3 bedroom house, along with the installation of cavity wall insulation, at an average price of £850 (£500 – Stormdry application; £350 – cavity wall insulation installation), an even faster payback period of just over 4 years can be expected. A long term energy bill saving of over 25% is possible with cavity wall insulation that has been protected by Stormdry.

Less Common Methods

If your property does not have a cavity wall, similar results can be obtained through the use of loft or roof insulation. Stormdry can also be applied to gable ends, chimneys and roofs to make sure the same level of protection is provided to the loft or roof insulation. 

In the case of single skin walls, Stormdry can also be a less high cost alternative to solid wall insulation, which has a long payback period of at least 14 years in a gas heated property. Solid wall insulation, either internal or external, can provide high levels of insulation but the installation cost and level of disruption to the householder is very high when compared to other forms of insulation. 

Further Information

Each building is different and it is always advisable to get an expert opinion on your particular property. If you wish to obtain advice on waterproof coatings or find contractors able to carry out Stormdry applications, contact Safeguard Europe’s technical department on 01403 210 204.

To continue research into insulation methods, there is a wealth of information on both and All figures and estimates from this article were gathered from these sources.

Stormdry has also been subjected to extensive testing by Safeguard Europe and all findings can be viewed on the test reports page, the energy saving analysis and insulation protection report are of particular note.