Retrofitting Services

It is crucial that existing buildings are maintained and operated in a sustainable manner.

Boland Payeh Azar follows a systematic approach to optimizing the sustainability of existing buildings guided by the requirements of ASHRAE Energy Auditing Procedures which involves analyzing the building’s operation and recommending cost-effective efficiency measures.

We do a thorough Gap-Analysis in order to re-design buildings to meet BREEAM/LEED requirements and International Energy Conservation Code (IECC) in IRAN, allowing for a better ROI for clients.

Our services in Buildings Retrofitting construction and consultancy include:

  • Building Architectural Retofitting
  • Building Energy Efficiency Retrofitting
  • Building Structural Retrofitting
  • Building Seismic Retrofitting
  • Building Mechanical and Electrical Utilities Retrofitting
  • Building Retrofitting with Energy Management System (BEMS) and Automation Systems
  • Building Integrate Photovoltaic systems (BIPV)

Existing Building Retrofitting

We follow a systematic approach to optimizing the sustainability of existing buildings guided by the requirements of ASHRAE Energy Auditing Procedures which involves analyzing the building’s operation and recommending cost-effective efficiency measures.

Our Retorifitting Services follow Standard Systematic Approach

The process of retrofitting involves the careful balancing of different elements and their effects on the overall performance of a building. A change in one part of a building can affect another, and sometimes this is only apparent after irreversible defects have occurred. For example:

  • Sealing buildings to improve their air-tightness can cause condensation problems.
  • Insulating a roof without also ventilating it can the cause decay of timber structure.
  • Internal wall insulation will remove the benefits of thermal mass which may have a detrimental effect on fuel usage.
  • External wall insulation will prevent the thermal store of heat from solar gain to be utilised within the building.
  • Poorly installed cavity wall insulation can create cold spots that then have damp problems that are extremely difficult to rectify.
  • Pre-existing problems can be covered up, and so more difficult to diagnose and rectify.

Some of the most common problems facing retrofit include: under-ventilation, condensation, air leakage, mould issues, rising damp, interstitial condensation, and overheating.

It is very important therefore that these and other risks are understood and managed in a way that is appropriate to each individual project. Standard solutions should not simply be rolled out without proper consideration, and it is vital that care is taken to ensure high quality installation. At each of the four retrofit processes – assessment, design, installation and operation – it is advisable to have ‘retrofit watch points’ to help avoid problems such as:

  • Poor management of trades.
  • Poor integration of trades.
  • The adoption of inappropriate solutions.
  • Overambitious performance gains claimed by designers and suppliers.
  • A lack of robustness of detailed design.
  • Fragmented procurement and delivery (lack of overall responsibility and ownership).
  • Poor construction sequencing and commissioning.
  • Inadequate handover and user guidance.

Once a building has been retrofitted, the process of post-occupancy evaluation is important in determining its overall success and ensuring that lessons are learned for future projects. This can involve monitoring fuel use, occupant surveys, air permeability testing, and thermographic surveys and so on.

Retrofit Techniques:

Wall definition

Approved document BFire Safety, Volume 1 Dwelling houses, suggests that for the purpose of the performance of wall linings, a wall includes:

  • The surface of glazing (except glazing in doors).
  • Any part of a ceiling which slopes at an angle of more than 70º to the horizontal.

But a wall does not include:

  • Doors and door frames.
  • Window frames and frames in which glazing is fitted.
  • Architraves, cover moulds, picture rails, skirtings and similar narrow members.
  • Fireplace surrounds, mantle shelves and fitted furniture.

However, Approved document C, Site preparation and resistance to contaminants and moisture, suggests that a wall is:

‘Any opaque part of the external envelope of a building that is at an angle of 70° or more to the horizontal.’

For more information, see What are walls made of?

Buttressing wall

A wall designed and constructed to afford lateral support to another wall perpendicular to it, support being provided from the base to the top of the wall.

Cavity wall

A wall constructed from two skins of masonry, the outer skin of which can be brickwork or blockwork and the inner skin of which is generally of blockwork, separated by a cavity to prevent the penetration of moisture and to allow for the installation of thermal insulation.

Compartment wall

A wall constructed to create a compartment, forming a barrier to the spread of smoke, heat and toxic gases.

Curtain wall

A non-structural cladding system for the external walls of buildings.

See Curtain wall for more information.

External wall

A wall forming the external enclosure of a building, including part of a roof pitched at an angle of more than 70° to the horizontal, if that part of the roof adjoins a space within the building to which persons have access (but not access only for repair or maintenance).

Internal load-bearing wall

A wall providing separation between the internal spaces of a building where the wall is also required to transfer loads from other parts of the structure to the foundations.

Partition wall

A non-load bearing wall that separates the internal spaces of a building.

See Partition wall for more information.

Party wall

A wall that stands on the lands of 2 or more owners or a wall that is on one owner’s land but is used by 2 or more owners to separate their buildings.

See Party wall for more information.


A wall comprising an outer skin of panels and an airtight insulated backing wall separated by a ventilated cavity. Some water may penetrate into the cavity but the rainscreen is intended to provide protection from direct rain.

See Rainscreen for more information.

Separating wall

A wall or part of a wall which is common to adjoining buildings.

Solid wall

A wall constructed of one skin of masonry which can consist of brick or blockwork and does not include a cavity between the interior and exterior.

Supported wall

A wall to which lateral support is afforded by a combination of buttressing wallspiers or chimneys acting in conjunction with floor(s) or roof.

Trombe wall

A construction that uses a combination of thermal mass and glazing to collect and store solar radiation so that it can be used to heat buildings.

See Trombe wall for more information

Insulation and ventilation systems.

A roof is a structure forming the upper covering of a building or other shelter. Its primary purpose is generally to provide protection from the elements, but it may also contribute to safety, security, privacy, insulation and so on. Roofs may have openings or windows within them to allow light into the buildings, as well as providing, access, ventilation, views and so on. They also frequently include other features such as chimneys, communications infrastructure, building services, drainage, lighting, access routes and so on.

Roofs can be constructed from a wide variety of materials and in a wide variety of shapes depending on the requirements they have to satisfy, the local climate, the availability of materials and skills, the span to be covered and so on.

This article provides links to further information about a range of roof types.

Click on the links below to access more information:

Draught proofing or replacement high-performance doors.

Doors are openable barriers at the entrance to buildings, rooms or other spaces such as cupboards that allow people, vehicles or goods to enter and leave. They most commonly swing on hinges and include furniture or ironmongery that allows them to open, close, stay closed and sometimes to lock.

There are a very wide variety of door types:

  • Interior / exterior.
  • Fire rated / escape.
  • Accessible.
  • Integral frame / separate frame or frameless.
  • Solid, transparent or translucent, either in part (such as vision panels) or in their entirety. Transparent doors may include manifestation as required by part k of the building regulations.
  • Manually operated or powered.
  • One leaf or two leaf.
  • Hinged inwards, outward or both, or revolving, rolling or sliding.
  • Acoustic.
  • Energy rated.
  • Timber (hollow or solid core), aluminiumsteelUPVCglass, and so on.

Installation of double or triple glazing, draught proofing of existing glazing.

Windows are openings fitted with glass to admit light and allow people to see out. They are often openable to allow ventilation.

Although the historic use of glass dates back to the Romans, glass windows only became common domestically in England in the early-17th century, gradually becoming more versatile and widespread as plate glass processes were perfected during the Industrial Age.

England, France, Ireland and Scotland introduced a window tax during the 18th and 19th centuries which was payable based on the number of windows in a house. It is still common to see buildings from that period with windows that were bricked-up to avoid the tax. The tax was repealed in 1851.

Windows are can include a number of different components:

  • Light: The area between the outer parts of a window, usually filled with a glass pane.
  • Frame: This holds the light in place and supports the window system.
  • Lintel: A beam over the top of a window.
  • Jamb: The vertical parts forming the sides of the frame.
  • Sill (or cill): The bottom piece in a window frame, often projecting beyond the line of the wall.
  • Mullion: A vertical element between two window units or lights.
  • Transom: A horizontal element between two window units or lights.
  • Head: The uppermost member of the frame.
  • Sash: The frame holding the glazing.
  • Casement: A window (or sash) attached to its frame by one or more hinges.

Installation of insulation.

According to Approved Document C, a the ‘lower horizontal surface of any space in a building including finishes that are laid as part of the permanent construction.’

floor typically provides:

  • Structural support for the contents of the room, its occupants, and the weight of the flooritself.
  • Resistance to the passage of moisture, heat and sound.
  • A surface finish which may contribute to the look, feel and acoustics of a space.

Very broadly, floor construction tend to be solid floors, built up from the ground, or suspended floors, supported by wall structures. There are a very wide range of variations around these basic types. The intended use of the floor, its location, the structure of the rest of the building, and the required floor finish will determine which of the many variations is most suitable for a particular application.

Solid floors tend to require little maintenance and are less prone to movement. They are often built up from the following components:

  • Sub-base: Well-compacted building rubble or loose stone-based material.
  • Hardcore: Suitable filling material to make the required level, and create a solid base.
  • Damp-proof membrane (DPM): An impervious layer such as heavy duty polythene sheeting.
  • Concrete bed: Provides a solid level surface.
  • Insulation to limit heat transfer with the ground.
  • Screed: Usually a sand and cement mix laid to prepare for the installation of a floor covering.
  • Finish: Such as carpet, tiles and so on.

The thicknesses of the layers and their order will depend on the specific use required and the ground conditions.

New controls, occupancy sensors, Light-Emitting Diode (LED) lighting and other low energy technologies.

The term ‘lighting’ refers to equipment the primary purpose of which is to produce light. This is typically some form of lamp. However, lighting can also refer to the use of natural light to provide illumination.

The level of light on a surface is described as ‘Illuminance’ and is measured in lux (lx), where one lux is equal to one lumen per square metre (lm/m²) and a lumen is the SI unit (International System) of luminous flux, describing the quantity of light emitted by a lamp or received at a surface.

Articles on Designing Buildings Wiki about lighting include:

Plant, pumps, piping and controls upgrade.

Chillers are used in buildings to provide cooling. This is typically for heating, ventilation and air conditioning (HVAC) systems providing thermal comfort for occupants, but they can also be used to provide cooling for industrial processes.

Chillers remove heat from a liquid through a refrigeration cycle in a process that is essentially the same as that used to cool domestic fridges. They can work on compression or absorption:

  • In compression systems, a liquid refrigerant with a low boiling point absorbs heat from water returning from the building and boils in an evaporator to form a gas. The gas is then compressed, which increases its temperature further. The gas is then condensed, releasing its latent heat which is rejected to the outside. The process then repeats.
  • Absorption refrigeration works on a similar basis, with a refrigerant that boils at low temperature and pressure, however, in this case, the refrigerant gas is then absorbed in a solution which is then heated in a ‘generator’ so that the refrigerant evaporates again, but this time at a higher pressure and temperature. The gas is then condensed, releasing its latent heat which is rejected to the outside. The process then repeats.

The rejection of heat from chiller units can be achieved by:

  • Air cooling, which rejects heat to the outside air by circulating it through the condenser.
  • Evaporative cooing, which uses the addition of a water mist to the air to enhance the cooing effect.
  • Water cooling, which is generally suited to large systems and requires connection to cooling towers.

Heat recovery can be used to allow the rejected heat from chiller units to be re-used for space heating or to provide hot water.

The exact opposite of the refrigeration process can be achieved by a heat pump, which reverses the cycle so that heat is supplied to the building rather than cooling. Some systems are reversible, able to supple either heat or cooling. See Heat pump for more information.

Typically in heating, ventilation and air conditioning systems, chiller units produce chilled waterthat is piped to air handling units (or fan coil units) where it is used to cool the air that ventilates the building. The ‘warmed’ water is then returned to the chiller unit to be re-cooled. The process of cooling ventilation air will also reduce its humidity.

Air handling units may also include a heating coil for times when heating rather than cooling is required. In some situations, air that has already been cooled will be re-heated (typically in simple, single duct constant air voume (VAC) systems). Whilst this may seem wasteful, in buildings where there are some minor local variations in thermal demand it can be more economic than it would be to provide two separate air ducting networks.

Chilled water might be supplied to other components, such as chilled beamschilled ceilingsand so on.

An alternative system supplies the refrigerant itself (rather than chilled water) to terminal units supplying different thermal zonesVariable refrigerant flow (VRF) systems use a single external condensing unit and multiple internal evaporators and can be more efficient, more compact and offer greater flexibility than other HVAC systems. See Variable refrigerant flow for more information.

Some refrigerants have both ozone depletion potential (ODP) and global warming potential (GWP), and as a consequence refrigerants such as CFC’s (chlorofluorocarbons) are banned. New equipment using HCFCs ((hydrochlorofluorocarbons such as R22 and R408A) was banned in 2001 (2004 for small systems), and the use of virgin HCFC’s was banned in 2010, when it also became illegal to manufacture HCFC refrigerants or for suppliers to keep them in stock. From January 1st ۲۰۱۵ the use of HCFC’s was prohibited in any form, even for maintenance. The use of HFC’s (hydrofluorocarbons, including 417A, 422A, 422D, 424A, 427A, 428A and 434A) continues to be permitted. Other refrigerants include, ammonia (common in absorption refrigeration), carbon dioxide and non-halogenated hydrocarbons.

It is important that the design of HVAC systems is considered as a part of the overall design process for the building, and not seen as an add on at the end. It is also important that HVACsystems are regularly maintained to ensure optimum performance and occupant comfort.

Installation of high-efficiency condensing boilers or micro CHP, new controls, connection to low carbon community heating systems.

Boilers are typically used to heat water to feed heating systems or to supply hot water, or both. Boilers are most commonly fuelled by:

There are a very wide range of boilers available depending on; size, fuel type, efficiency and application, and ranging from compact units used for domestic heating, to very large boilersused for industrial processes. For more information see:

Upgrade, or replace with air or ground source heat pumps or passive cooling.


Use of the term ‘air conditioning’ (AC) can be confusing.

In some of the strictest definitions, air conditioning is used to describe systems that control the moisture content of air, that is, its humidity. This can include humidification and dehumidification. Humidity control can be important for; the comfort of building occupants, to reduce the incidence of condensation (both surface and interstitial), for specialist environments such as swimming pools, and where the protection of sensitive items requires particular conditions.

However, dehumidification of air is generally achieved by cooling. As the temperature of air falls, it is less able to ‘hold’ moisture, that is, saturation water vapour density falls, and so relative humidity rises. When relative humidity reaches 100%, the air will be saturated. This is described as the ‘dew point‘. If the air continues to cool, moisture will begin to condense, dehumidifying the air.

This means that humidity control and cooling are often considered together as ‘air conditioning’. Cooling and dehumidification are important contributors to thermal comfort. This is because the ability to perspire, and so to lose heat by evaporation from the skin, is limited by the humidity of the air.

As a result, remaining cool is dependent on both temperature and humidity (as well as a number of other factors, see Thermal comfort for more information). So a combination of reduced air temperature, and reduced humidity helps people to remain cool.

The cooling of air alone, often described as ‘air conditioning’ is more correctly referred to as ‘comfort cooling’. However, because it cools the air, comfort cooling may include some incidental dehumidification.

Other definitions of air conditioning describe it as the process of conditioning supply air to:

CIBSE Guide B. Heating, Ventilating, Air Conditioning and Refrigeration suggests that:

Air conditioning involves full control over the humidity within the conditioned space as well as temperature control.’ CIBSE suggest that ‘close control air conditioning‘ might be defined as the control of temperature to within 1°K and relative humidity to within 10%. This requires a complex process of dehumidification and cooling, reheating and humidification.

The Department for Communities and Local Government (CLG) guide, Improving the energy efficiency of our buildings, A guide to air conditioning inspections for buildings, December 2012 suggests that an air conditioning system is defined as ‘a combination of all componentsrequired to provide a form of air treatment in which the temperature is controlled, or can be lowered, and includes systems which combine such air treatment with the control of ventilationhumidity and air cleanliness’.

This includes fixed, self-contained systems, such as split systems and centralised systems. Mechanical ventilation systems that provide no mechanical cooling, but serve spaces that are cooled by other means are included. Any components contained in air conditioning systems that are only intended to provide heating are excluded.


In mechanically ventilated commercial developments, air conditioning is often provided by air handling units (AHU) connected to ductwork that supplies air to and extracts air from internal spaces. Alternatively, air handling units can be used to supply and extract air direct to a space.

Air handling units typically comprise an insulated box that might include some, or all of the following components; filter racks or chambers, a fan (or blower), heatingcooling and dehumidification, sound attenuators and dampersAir handling units that consist of only a fan and a heating or cooling element, located within the space they are serving, may be referred to as fan coil units (FCU).

Cooling itself can be generated either within the unit itself, or can be provided by connection to central chillers.

Installation of photovoltaics, solar thermal heating, passive solar heating, wind energy, wood and organic waste power sourced heating or power plant, micro-hydro power, and so on.


Our society on earth is heavily dependent on fossil fuels such as oil, gas and coal, and is likely to remain dependent on them for much of this century (Odell, 2009).

Every year we emit more than 20 billion tonnes of carbon into the atmosphere by burning fossil fuels, half of which is absorbed in the seas and by vegetation, and half of which remains in the atmosphere (Comby, 2008). The impact on human and natural systems is potentially irreparable (Schellnhuber et al, 2006). In addition, as fuels deplete and demand increases, so supplies become more vulnerable to disruption.

According to the International Energy Agency (IEA, 1999) ‘The world is in the early stages of an inevitable transition to a sustainable energy system that will be largely dependent on renewable resources’. In 2009, US President Barack Obama said, “To truly transform our economy, protect our security, and save our planet from the ravages of climate change, we need to ultimately make clean, renewable energy the profitable kind of energy.”

In 2007 European Union (EU) countries committed to set a binding target that 20% of the EU’s total energy supply should come from renewables by 2020 (European Union Committee, 2008). For the UK the target is 15%, almost a seven-fold increase in the share of renewables in scarcely more than a decade (HM Government, 2009).

Renewable energy

Renewable energy is derived from sources which are naturally replenished or are practically inexhaustible. They are often described as ‘clean’, ‘green’ or ‘sustainable‘ forms of energy because of their minimal environmental impact compared to fossil fuels.

However, there is some controversy about which forms of energy are genuinely renewable, as there are inevitable environmental consequences from any form of energy production and consumption:

The national planning policy framework (nppf) suggests that renewable and low-carbon energy: ‘Includes energy for heating and cooling as well as generating electricityRenewable energy covers those energy flows that occur naturally and repeatedly in the environment – from the wind, the fall of water, the movement of the oceans, from the sun and also from biomass and deep geothermal heat. Low carbon technologies are those that can help reduce emissions (compared to conventional use of fossil fuels).’

Very broadly the range of energy production techniques that have been described as ‘renewable’ includes:


Solar photovoltaics.

Solar cells, or photovoltaic (PV) cells, convert sunlight directly into electricityPhotovoltaicsgets its name from the process of converting light (photons) to electricity (voltage). See Solar photovoltaics for more information.

Solar thermal energy.

The term ‘solar thermal‘ is used to describe a system where the energy from the sun is harvested to be used for its heat. Small scale solar thermal collectors can be used for heatingswimming pools or supplying building heating systems. Large scale solar thermal collectors use mirrors or lenses to focus solar radiation; allowing much higher temperatures to be generated. See solar thermal systems and Large scale solar thermal energy for more information.

NB The use of the term ‘solar thermal‘ is also associated with the integration of ‘passive’ heating and cooling technologies in buildings.

Geothermal energy.

Geothermal energy is the second most abundant source of heat on earth after solar energy. It is the natural heat energy stored in the earth itself. Geothermal temperature increases with depth in the earth’s crust. Using the technology available at present, it has been found that the average geothermal gradient is about 3°C per 100m (Dincer et al., 2007). Geothermal energyhas been used on a commercial scale for over 100 years and more than 70 countries now exploit geothermal resources for electricity generation, space heating, hot water supply, cooling, industrial and agricultural uses. See Geothermal energy for more information (Batchelor, 2005).

Heat pumps.

Ground source heat pumps.

The temperature of the surface layers of the ground remains fairly constant below a depth of approximately 7-10m, at the mean ambient air temperature regardless of the time of year. Depending on the location and depth, this temperature is typically between 7°C and 13°C in the UK. This means that it can be used to as a heat source in the winter (and as a source of coolth in the summer). A heat pump works by using the evaporation and condensing of a refrigerant to move heat from one place to another. An evaporator (analogous to the loop in the cold part of a fridge) takes heat from water in a ground loop; a condenser (analogous to the hot loop on the back of a fridge) gives up heat to a hot water tank which feeds a distribution system. See ground source heat pumps for more information.

Air-source heat pumps

Air-source heat pumps extract heat from the outside air in a similar way to ground source heat pumps. This can be used to supply heat to radiators, hot air systems or hot water systems.

Water source heat pumps

Water source heat pumps operate on a similar principal but use watercourses as a heat source.

Tidal power

Tidal Range

Tidal Range is the difference in height between high and low tide. Tidal barrages or tidal lagoons can capture the tide, and release it through turbines to generate electricity. Turbine blades can be of a size and speed that allow large fish to freely enter and exit without harm. However, there is concern that enclosing large areas can destroy tidal habitats.

The Swansea Bay tidal lagoon is calculated to save 216,000 tonnes of CO2 annually which is equivalent to taking 81,000 cars off the road. See tidal lagoons for more information. The UK‘s total theoretical tidal range resource is estimated to be between 25 and 30GWs (12% of current UK electricity demand). Ref DECC Wave and tidal energy: part of the UK’s energy mix

Tidal Stream

Tidal stream is the flow of water resulting from the continual ebb and flood of the tide. Tidal turbines can generate electricity from this flow in a similar way to wind turbines. This is particularly effective in areas where narrow channels or headlands increase the tidal flow.

Wave power

Wind blowing across the surface of water causes waves. Wave energy can be captured by a number of methods to power turbines that generate electricity.

Wave and tidal stream energy could meet up to 20% of the UK‘s current electricity demand. Ref DECC Wave and tidal energy: part of the UK’s energy mix.

Hydro electric

Moving water can be used to generate electricity at both large and small scales. The UKgenerates approximately 1.5% of its electricity is generated by this method, largely by creating dams to capture water and then discharging it through turbines. (ref DECC Harnessing hydroelectric power January 2013)


Wind energy can be converted into electricity by wind turbines. These can be onshore or offshore, large scale commercial wind farms or small domestic units. Wind energy generation in the UK is growing rapidly, however, wind turbines have proved controversial because of their impact on the landscape and the fact that they only generate electricity ۷۰-۸۵% of the time. Ref Renewable UK


Biomass is a generic term referring to organic materials that can be used as fuelsBiomassdiffers from fossil fuels because of the timescale required for replacement. Whilst both take carbon out of the environment during their creation, before releasing it when used as a fuel, fossil fuels deplete faster than they are replaced and so are not sustainable whereas biomasscan be replaced relatively quickly and so may be considered ‘carbon neutral’. Solid bioenergy options include woodchips and pellets. Using these types of biomass fuel as a heating source is well established across Europe and the UK.


Combustion / incineration

Waste products can be incinerated at around 850°C and the energy recovered as electricity or heat.

Gasification and pyrolysis

Waste fuels can be heated with little or no oxygen present to produce gases which can be used to generate energy.

Anaerobic digestion / biogas

Biomass can be broken down by micro-organisms through a process of anaerobic digestion to produce methane-rich biogas that can be used as a fuel. The waste can also be used as a fertiliser.

Limitations of renewable energy

A key disadvantage of renewable energy at present lies in the rate at which it can be produced. Despite its successes, renewable energy production remains limited, partly because of the costs of the new technologies required and partly because their efficiency and productivity is partially dependent on variables such as the weather. A study conducted by The Renewable Energy Foundation revealed that the UK has missed its 2010 targets by a ‘large margin‘ (REF, 2011).

Renewable energy may also face the challenge of land constraint. For example, replacing crude oil-derived fuels by bio fuels would require between 1,000 and 10,000 times larger areas for crops than the land used by oil field infrastructures, and shifting from coal-fired to wind-generated electricity would require 10 to 100 times more space (Smil, 2006). Land issues apply to most renewable energies, along with direct or indirect impacts on natural habitats, the visual environment and loss of agricultural land.

These impacts can be seen in countries such as Brazil, Malaysia and Indonesia as producer countries of biofuels and Morocco, Libya, and Jordan where solar power plants are installed.

Nuclear energy

Although some sources claim that Uranium is inexhaustible with 4 billion tons dissolved in sea water, and that it can power the globe for 60,000-years at present rates (Comby, 2008; Fetter, 2009); there are concerns about the current state of available sources and the costs of processing that would be needed to extract uranium from sea water.

In addition, radioactive wastes are difficult and costly to dispose of and there is widespread concern about the diversion of nuclear materials to weapons production, as well as nuclear plants‘ vulnerability to attack. As a consequence, nuclear power may not be seen as a long-term option.

However, increasing C02 emission, rising demand and the limitations of renewable sources creates a dilemma. “If you don’t want nuclear, there are hard choices to be made on other issues” (Fitzgerald, 2005). For the time being at least, the UK government has chosen to support nuclear power as a low-carbon (rather than renewable) source of energy. This may provide some energy security whilst giving time for renewable energy technologies to be perfected.


A number of incentives have been introduced by the UK government to encourage the take-up of renewable energy technologies.

Feed in tariff

The feed in tariff scheme enables consumers to receive payments from their energy supplierfor renewable or low-carbon electricity that they generate, whether they use it themselves, or export surplus back to the grid.

Renewable heat incentive

The renewable heat incentive is a similar scheme to the feed in tariff scheme, but for heat generation. At present it is only available to the non-domestic sector, but the scheme is expected to extend to households in 2014 (ref Increasing the use of low-carbon technologies).

Green deal

Under the green deal scheme, a ‘green deal provider’ finances the up-front costs of installing energy efficiency measures, and the consumer’s energy supplier adds a ‘green deal charge’ to the consumer’s bill. The range of energy efficiency measures that might qualify under the green deal include (amongst other measures):

See Green deal for more information.

Climate change levy

The climate change levy (CCL) is a tax chargeable on commercial energy suppliersElectricitygenerated from renewable sources is exempt from the climate change levy.

Installation of low-flow equipment such as water fittings, shower heads, dual flush WC’s, rainwater harvesting, and so on.


Water is a critical and finite resource. It covers over 71% of the Earth’s surface and is essential for life, playing a key role in the production of food, human health and sustaining the natural environment.

However, water, particularly of drinking water quality, is becoming increasingly scarce in most of the populated regions of the planet. The pressure is on to reduce water demand by reducing wastage, to reuse or recycle as much as possible, and to look at other means of minimising our impact on the water environment. Overall we must be more efficient with our water utilisation.

This notion that it is important to conserve water is not a recent one. Whether it is the intricate reservoir and sewage systems of the Indus or the more aqueduct systems found in imperial Rome, the need to use water efficiently has been innate in human populations since the birth of modern civilizations. However, we now need to find new ways to conserve water and to use it efficiently.

The national and international context

Technically, there is enough freshwater on Earth to fulfil the needs of the global population, but a combination of factors mean that there are significant scarcity issues in many areas:

  • Demand distribution does not match resource distribution. Population densities are becoming more localised, consumption patterns are changing, and new demands are emerging (for example, bio-fuels could become a significant water user of the future). This all stresses the resource at a local and regional level.
  • Social access. In many places there is sufficient water, but people cannot access it due to asymmetric power relations, poverty and related inequalities.

Climate change is accelerating global water circulation, amplifying climate variability and temporal water scarcity.

Water Consrvation project approach

The various building rating schemes all reflect the heirarchical approach of reducing demand for water at source, ensuring efficient distribution (including metering, leakage detection etc), and then use of alternative sources.

Reduce demand at source – efficiency

There are a number of relatively straight-forward water efficiency measures that can be made that not only conserve water but also save money. Water efficiency should be specified on all projects, unless it can be proven to be to the detriment of other systems.

A brief overview of the potential savings are outlined below:

Baseline water consumption can be reduced at source through passive or active measures.

Passive measures

Passive measures are those which require no behaviour change by the user. They include:


  • Water Saving Taps (efficient versions are as low as 1.7 L/min) are often the same price as less efficient models.
  • Appropriate sink sizing. If a sink does not need to be completely filled to use it, then a smaller sink could be specified.
  • Foam soap requires little water to remove, and generally means less soap and water are used.

Low flow toilets

  • Toilets are typically the largest water user in non-residential developments, allowing significant savings to be made.
  • Modern standard cisterns have a volume of 6L. Efficient designs can bring the average flush volume down to 3L.
  • Siphon mechanism. Low flush (4.5L) versions are available, but they are slow to refill the cistern and are only available in single flush.
  • Drop valve mechanism. Allows quick cistern refill (good for high frequency use) but the valve will eventually leak, and it is not as robust as the siphon. It may also require maintenance to remove scale deposits.
  • Delayed action inlet valve. This prevents water flowing into the cistern before the flush is complete.
  • Interruptible flush. The user stops the flush by releasing the lever when the pan is clear.
  • Composting. A tank or chamber is installed below the toilet bowl to collect waste. Liquid waste can be collected separately, diluted and used as fertiliser for trees and flowers. The solid waste can be collected after 6months to a year and used as compost.
  • Vacuum. These use air rather than water to flush, and can be used where gravity drainage is problematic. Some designs combine an air and water flush.

Water efficient appliances

The Environment Agency reports that dishwashers and washing machines account for over 16% of domestic water consumption. Typically, washing machines use less than 50 L/cycle, and dishwashers less than 15L/cycle. Efficient versions use much less (40L/cycle and 10L/cycle), and modern washing machines often have a ‘half load’ cycle or intelligent monitoring to only use as much water as needed.

Efficient distribution

  • Leak detection and water meters can help highlight excessive use, or unusual usage patterns.
  • All modern domestic pipework should be fitted with an isolator valve, with integral flow restrictor. However, should the water pressure fall, the flow may no longer be adequate. There may also be difficulties with blockages in hard-water areas due to scale buildup.
  • Water mains are usually operated at about 2-4bar, but in some cases higher pressures than necessary can be delivered to the lower floors of tall buildings. Over-high water pressure can result in excessive water consumption, cause or exacerbate leakage and put additional wear and tear on the distribution system. Pressure reducing valves (PRVs) can be used to control the pressure in the incoming main or distribution system (e.g. in the supply to each floor, the down service of a gravity-fed system, or the risers in a pumped system). They can be pre-set or adjustable, and accept delivery pressures of up to 25bar and deliver pressure of 1.5 to 6 bar under variable flow conditions.
  • Lag pipework to reduce heat loss/gain and so avoid the practice of running water to drain until it achieves the correct temperature.
  • A solenoid valve linked to a lighting control module via a PIR will shut off the water supply to the toilet area to prevent wastage due to leaks.

Alternative sources

Examples of alternative sources for water utilisation are rainwater harvestinggreywater reuse and blackwater reclamation.

Rainwater harvesting

In areas where there is insufficient surface water or where groundwater is particularly inaccessible but there is an abundance of rainwater, rainwater harvesting can be effective.

Despite the fact that the United Kingdom receives a high level of rainfall, water resources are under serious pressure. Rainwater harvesting systems range from the humble water butt used to water domestic gardens, to schemes such as the Millennium Dome in London in 2000, where rainwater was collected from the 100,000 sqm roof and filtered through reed beds in the landscape before being returned to the Dome and used to flush the 700 toilets. Typically, rainwater is collected from building roofs and then stored in a tank for non-potable use. Most non-potable water applications do not require UV or chemical treatment, although treatment might be appropriate depending on the potential for human exposure.

The code for sustainable homes (۲۰۰۶) encourages the installation of rainwater harvestingsystems in newly built homes for use in the garden, washing clothes and dishes and other domestic uses such as flushing toilets. It has been reported that this can reduce the amount of mains water being used by up to 50%. The Environment Agency suggests that, “Reducing the volume of mains water supplied means that less water is taken from lakes, rivers and aquifers and more is left to benefit ecosystems and help sustain the water environment”.

See Rainwater harvesting for more information

Grey water recycling

Greywater is wastewater from showers, baths, washbasins, washing machines and kitchen sinks. It is possible to collect such water and, after treatment, use it for purposes that do not require drinking water quality, such as toilet flushing and garden watering. (Environment Agency, 2011). This greatly reduces the demand on mains water as well as reducing the volume of water discharged into sewage systems.

As well as conserving water this will also save users money on their water bills (if they have water metres installed). According to the Environment Agency (۲۰۱۱), greywater recyclingsystems have the potential to reduce the amount of mains water used in the home by about a third.

The limitations of initiatives such as rainwater harvesting and greywater harvesting are that even though it reduces demand for mains water, it does not actually contribute to a reduction in water consumption. In addition, long payback times combined with small storage volumes mean it can be less effective than other water conservation measures.


There are many challenges in implementing sustainable water management practices. There is a social reluctance to change habits and routines, and it is a field laden with expectations and prescriptive legislation. This means that the physical systems which make up our current infrastructure have a high degree of inertia over time. Change will only happen slowly, alongside the development of knowledge, understanding and acceptance.

The safe implementation of water recycling and reuse in all countries and for all types of applications requires the development of a global framework including regulatory requirements and policies, water quality control and risk assessment, design and operational recommendations with codes of practice, as well as communication and education with stakeholder and community involvement.

Peak saving through thermal energy storage, onsite electricity generation, combined heat and power, and so on.

The term ‘electricity‘ refers to the presence and flow of an electric charge. The most common form is that which is used to power appliances, machines and devices by the flow of electrons through conductors such as copper wires.

Static electricity refers to electric charges that are static and not moving, while an electric current is created when charges are dynamic and moving.

Articles relating to electricity on Designing Buildings Wiki:

Smart meter

The Government’s vision is that every home and small business in the UK will have a smart meter by 2020 . This will require the replacement of over 53 m gas and electricity meters requiring 30 m visits to homes and small business.

Consumers will be offered an In-Home Display (IHD) and this will provide real time information on their energy use both in terms of consumption and cost as well as other useful information. This will allow the consumer to manage their energy, save money and reduce carbon emissions. Smart meters will also allow for easier switching between suppliers, end estimatedbilling and eliminate the need for meter readers to visit premises.

To protect consumers the Government has put safeguards in place to ensure that consumers are not subject to any sales pressure during meter installation and that consumers’ privacy is protected by providing them with control over their smart meter data.

By providing consumers with near real-time (potentially 30 minute settlement) data that reflects the true cost of supplying electricity a whole new supply and demand relationship will be established. Smart meters will facilitate a more reactive, price driven, demand-response from the consumer. Time-of-Use Tariffs (TOUTs), enabled by smart meters, will mean that energy consumers will need to be much more aware of what they are using and when they are using it:

Domestic users, who represent one third of the total demand for electricity but two thirds of the volatility will progress from passive bill payers to highly informed energy consumers and producers”.

As the deployment of smart metering proceeds an increasing range of market-led devices will become available to help consumers manage their energy use including; enhanced energy displays, smart appliances and home automation tools. These will be able to securely connect to the smart meter receiving and reacting to gas and electricity consumption and pricing data.

The introduction of a smart grid and smart meters are important elements in de-carbonising electricity in the UK. As this happens the relationship between the supply and demand of electricity will become very much more dynamic and interactive. The price of electricity will move away from a relatively fixed tariff to one where it may change every half-an-hour as it does already for many non-domestic consumers.

While the changes will inevitably bring some problems and issues, the prediction is that the average household bill will be reduced by between 5 per cent and 9 per cent between 2016 and 2030 compared to existing policies.