2. Green/Eco Design Principles

Fabric First


  • Energy that isn’t used is energy that doesn’t need to be generated. Since most of the energy we do use is still produced using fossil fuels (gas, coal, oil), by not using it we save on the climate change gas emissions (e.g. CO2) resulting from the of burning fossil fuels.
  • Modern energy-efficient design is encompassed by the ‘Fabric First’ concept. This means that what matters above all, is to construct buildings that use as little energy as possible whilst using materials that have been made using as little energy as possible (‘embodied energy’).
  • In practice this means that we make the walls, roofs and floors of our houses as resistant to the passage of heat as we can.
  • At the same time, we use energy from the sun to our best advantage in warming our houses.
  • Only when we have ensured that we have built the most energy efficient house will we start looking at adding renewable technology such as solar panels, solar thermal and heat pumps.
Heat lost through the building envelope is balanced by heat gained from the sun


Energy efficiency is best achieved by designing a careful balance between energy conservation and energy (usually solar) gain. Computer programs will do a lot of the heavy lifting of the calculations.

  • Less floor area = less area to heat = less energy used
  • Obviously cheaper to build
  • When planning your house, it is easy to keep adding more and more space. You can end up with far too much. Be tough on yourself and ask whether you really need it. By being efficient with space you can plough the money saved into something else like solar panels (heat or electricity).


  • Everyone is familiar with the way Sun shining through a window will warm the room.
  • Equally, we’re aware of how quickly heat can be lost through glazing.
  • The skill of using the Sun to heat your house is knowing how and when to use it.
  • In the Winter, Sunlight is at a premium, so we have to design our homes to make best use of it.
  • In the Summer, some Sun is useful, but too much can lead to overheating.


  • Orient the facade that includes the main living areas, within 30 degrees of South
  • Put living, dining, family areas to the South and utility, storage and bathrooms to the North.
  • Use trees and planting to shelter the house from cold Northerly winds


Small windows to the North minimise heat loss; Larger South-facing windows optimise the light and heat from the sun


  • Less glazing or higher insulation glazing to the North.
  • Beware overheating from low sun in the morning and late afternoon. You might find it an idea to put the kitchen on the eastern side where it can warm up quickly in the morning after a cold night. Plus, some find the morning sun is invigorating.
Locating the kitchen at the East side benefits from the morning sun



  • The amount of Sun we get in the Summer is increasing. In the South of England, the intensity of heat from the Sun will approach that experienced in places such as the South of France.
  • Use solar shading to minimise overheating in the Summer
  • A simple way is to install shading just over the top of windows to prevent the high-angled Summer Sun from reaching the glass.

  • Leaves provide shade in summer; In winter the sun can reach the walls of the house

  • You can use deciduous trees to reduce heat from the Sun in Summer and maximise it in Winter
  • Perhaps consider shutters if you are in the South of England - it’s what they use on the Continent to shade the sun and prevent heat escaping at night.
Sun louvres over the windows can prevent overheating in the middle of summer


The hot caravan and the cool stone house during summertime are caused by the very different ways of construction


  • If you’ve visited the Mediterranean you’ll know that houses with thick stone walls can keep cool whilst the Sun pounds the roof and walls outside.
  • The opposite is true if you’ve stayed in a caravan. Just as soon as the Sun shines on the thin aluminium skin, the temperature inside rises dramatically and quickly becomes uncomfortable.
  • The heat from the Sun penetrates the building fabric at different rates depending on the materials the wall or roof are made from. Slowing the heat is known as ‘Decrement Delay’ or ‘Thermal Buffering’.

  • Rising temperatures in the home will put people at risk of hyperthermia


  • High summertime home temperatures can easily put people, particularly the young and elderly, at high risk of overheating (Hyperthermia).

  • We'll all be familiar with climbing into a stiflingly hot loft during the summer


    Coventional cavity wall construction will lead to overheating through rising summertime temperatures


  • Rising temperatures in the UK will result in the overheating of homes even currently being constructed by the volume house builders
  • When it’s hot, the idea is to slow down the heat over a period of time so that when it comes out of the inside of the wall, the Sun outside has ceased to shine and the room temperature begins to fall.
Using wood fibre insulation in walls and roofs is one way of significantly increasing decrement delay


  • Windows provide free heat from the Sun
  • Windows lose more heat than the walls they’re set in.
  • Getting the balance right between window size and heat loss is a tricky design issue. Computer programs are used to optimise the window size.

  • The ideal window to wall area ratio

  • In a thermally efficient house, the percentage of window glazing to solid wall is usually between 25 - 35% on the South facade. More glazing makes the balance between heat gain and heat loss much more difficult and expensive.
  • Windows on the North facade of the house don’t get heat from the Sun, but still lose heat from the house - hence they should be smaller in size.
  • Window glazing itself can reduce heat loss dramatically when triple-glazed - though this tends to be very expensive. Your final budgeted design might be a balance between some windows being triple-glazed and others double-glazed. Again, your architect will work hard on getting the balance right.

Triple-glazing: very efficient but expensive (Credit: Green Building Store)
  • Where the temperature of the inside of your house is above the outside temperature, it will lose heat to the outside.
  • Heat is lost through the fabric of the roof, walls, windows and ground floor.
  • Heat is also lost through warm air leakage from inside to outside.
  • Just through how much surface area to the walls and roof compared with the volume of the house can affect the amount of heat lost from the building. This is the Surface to Volume Ratio or ‘Form Factor’.
  • Minimise the surface area to volume - that’s where the ‘envelope’ of the house gets close to a cube or hemisphere.
  • The diagram below shows 3 figures. The best volume - surface ratio is found in the sphere (1) but obviously it's not a brilliant shape for a house (people HAVE tried); Figure (3) is much more buildable, but the volume-surface ratio is poor - leading to unnecessary heat loss; Figure (2) or similar approaching the form of a cube is the best compromise, finding an optimum volume-shape ratio or 'form factor'.
Finding the best volume-surface ratio. No. 2 works best
Keep warm: Wrap-up tight!


Pack the walls, roof and ground floor to the max with insulation


  • Most heat loss can be significantly reduced by using Thermal Insulation
  • How quickly heat is lost depends on the materials the house is constructed from.
  • Some materials have much better Thermal Insulation qualities than others. Metal is a very bad insulant whereas wood fibre or wool have excellent insulation qualities - hence their use in buildings.
  • The measure of the effectiveness of a material to reduce the flow of heat through it is known as the ‘U-Value’. The lower the value, the better the insulation. More about U-Values


  • The U value tells you how much heat energy will pass through a 1 m² piece of the material in 1 second if there is a 1°C temperature difference between the two sides of the material.
  • An ideal wall U-Value would be in the order of 0.15 W/m²K and the very best triple-glazed windows would be around 0.15 W/m²K (Watts per square metre per degree Kelvin).
  • Another important factor involving heat loss is ‘Thermal Bridging’. This refers to materials that can conduct heat rapidly through the width of the wall. A typical Thermal Bridge would be a steel wall tie or a steel lintel over a window. Building regulations advise to minimise Thermal Bridging, but the calculations can get quite complicated. More about Thermal Bridging.
If you think you've added enough insulation, add some more



  • Before thermal efficiency became an issue, older houses relied on the likes of gaps in windows and around doors as well as other incidental openings in the building fabric, to provide ventilation to the interior. Particularly useful when open fires were in use.
  • In modern, much warmer buildings such openings in the fabric can result in considerable heat loss. Stand at an open front door when its cold outside and feel the warm air stream by. When air leaks from your house, not only is it wasting energy - you’re paying to heat the outside!
  • Airtightness Barriers are a feature of modern houses. Standards of Airtightness are included in the Building Regulations.
  • Getting an Airtightness Barrier to succeed needs skilful design by the Architect and careful installation by the Builder.
  • Air barriers are typically formed by a combination of proprietorial membranes in the wall construction combined with specialist tape for use around wall openings such as windows.


Mechanical Ventilation with Heat Recovery (MVHR) (credit: adm systems)


  • 'Insulate tight, Ventilate right' is an industry mantra.
  • With your house successfully sealed, you will be in need of ventilation. The key is controlled ventilation, the easiest way of which is to use mechanical ventilation.
  • The use of mechanics to ventilate the house is an anathema to some people who prefer to use ‘Passive Ventilation’ techniques. However although requiring infrequent attention and a power supply, Mechanical Ventilation is an assured method of getting fresh air into the house in just the right quantities. It is also key to implementing the Passivhaus Standard (see below).
  • Mechanical Ventilation with Heat Recovery (MVHR) will require ducting around your home. Typically, the air is introduced into bedrooms, and extracted from kitchens and bathrooms. The intake air and extract air are propelled by fans, and pass over a heat-exchanger, so that the intake air absorbs heat from the extract air.
  • Since the oil crisis of the 1970s, energy use standards have become a feature of building design.
  • In the UK, energy conservation has been included as part of the Building Regulations since 1976.
  • When it was first introduced, it was intended that the UK would become less dependent on imported oil and gas. From the late 1990s the major concern of Climate Change has become the more determined driver of regulation.
  • The Building Regulation energy efficiency standards have tightened over the years. However, because of pressure from the house building industry, the best standards are still a long way from being achieved.
  • The most important external intervention has been from Europe in the Passivhaus Standard. The standard is far more rigorous and demanding than Building Regulations but the result is often that houses can be built without heating systems at all as well as levels of comfort unknown in more conventional off-the-shelf housing.

Building Regulations

CO2 Emissions target

  • Part L: Conservation of fuel and power, cites the energy conservation standards applied to all buildings currently being built in the UK.
  • The ‘Regs’ specifically targets the amount of Carbon Dioxide (CO2) that a house generates in a year.
  • The maximum amount of CO2 that can be emitted is commensurate with the size and shape of the house. This target is known as the Target Emission Rate (TER). It is measured as the annual weight in kg of CO2 generated per square metre.
  • The actual calculated rate of CO2 generated specifically for your house is known as the Dwelling Emission Rate (DER).
  • The DER must not exceed the TER.

Fabric Efficiency target

  • Sitting alongside TER and DER, which deal with CO2 emissions, are the Target Fabric Energy Efficiency Rate (TFEE) and the Dwelling Fabric Energy Efficiency Rate (DFEE).
  • Although appearing similar and giving rise to much confusion, the aim of the Fabric Efficiency standard is to improve the way your house performs through the type and size of the materials making up the walls, roof and ground floor.
  • Again, like the TER and DER, Fabric Efficiency sets a notional efficiency rate according to the size of the proposed house. The Target Fabric Energy Efficiency Rate (TFEE) is the performance standard to be achieved or bettered and is measured in kilowatt-hours per square metre of floor area per year (kWh/m2/year).
  • The Architect will calculate the anticipated actual efficiency rate, or the Dwelling Fabric Efficiency Rate (DFEE) for your house and ensure that it achieves or betters the TFEE.


  • The Standard Assessment Procedure for the Energy Rating of Dwellings (SAP) is the method by which the energy performance of houses is calculated.
  • Programs are used by the Architect which follow the the assessment procedure and calculate emissions targets and fabric efficiency (see above).



  • The Passivhaus Standard is independent of Building Regulations and is not part of UK Government legislation.
  • It is much more stringent than the Building Regulations.
  • If the standard is met, it will provide your home with considerable energy efficiency and comfort.
  • Passivhaus is the ‘go-to’ standard for ‘Green’ architects and is being rapidly adopted by individuals as well as organisations.
  • Passivhaus, as its name suggests, originated in Germany in the 1990s.
  • Unlike the Building Regulations, Passivhaus does not deal in CO2 emissions rates. Instead it confines itself to addressing the amount of energy required to heat the house.
  • The headline rate, not to be exceeded, of heating demand is 15 kilowatt-hours per square metre of floor area per year (kWh/m2/year).
  • This rate is irrespective of the size or type of building.
  • As part of achieving this very low heating rate, the standard also includes a standard for airtightness which calls for no more than 0.6 air changes in the house every hour. (the Regs by comparison, and calculated differently, only require an approximate equivalent of 10 air changes per hour)


The environmental impacts of building materials result from the related energy use and emissions, the depletion of finite material resources, and the undesirable accumulation of materials in landfill. The activities causing these impacts include the mining and harvesting of raw materials, transporting materials, the use of hazardous materials, and the generation of construction waste. Through careful building design and material selection, we can reduce these impacts substantially.

Passivhaus home under construction


There’s usually a vast range of building products available on the market. Many are grouped in a way that they can do the same job within the building. Sorting them out can be hard work. Professional designers and builders spend a good deal of their time studying the potential of products to do the job needed of them. However, there are guiding principles, the main ones being:

Is it a product or material you like and want in your building?


Is it a product that will stand-up to the ravages of time, or will it fall apart in the first year. Materials and products that last are a particularly important consideration for the Green Self-Builder because of the amount of energy and material that are invested in a building product.

Window failure


Does the product/material do the job it claims - or is it a figment of the salesman’s imagination? Get expert advice and feel free to interrogate the manufacturer/supplier. Not always available, but look for third party certification - i.e. someone or some respectable organisation endorses it.

Is it affordable? Can the product/material justify its place in your building or is it a luxury? There might be a time during the build when you have to cut costs, so understanding your reasons for spending money at the outset is a useful exercise.

  • Think ‘lean’. Materials you don’t include in your build, don’t need to be made. Materials that aren’t made don’t have an environmental impact - and don’t cost anything!
  • The ‘Greenest’ material selection is that which minimises the quantity of material used. The less overall material you use to build the house, the lower the impact.


  • Assessing the overall environmental impact of a material/product is often quite difficult. Fortunately there are an increasing number of products appearing on the market that can tell you exactly what’s involved in their manufacturer. These products are accompanied by an Environmental Product Declaration (EPD). EPDs tell you about what materials and energy go into the manufacture of the product and what the consequences are of the manufacturing process in terms of waste and emissions into the atmosphere or water courses. EPDs are just information that you use to inform your decision. It’s important to understand that they are not Green Certificates/Labels or Endorsements of any kind.
  • Obviously it’s important that materials/products are chosen that have the minimum impact possible for their function.


Use salvaged materials wherever possible. There are plenty of materials available from demolished buildings ranging from bricks, timber, steel structure through to bathroom and kitchen fittings and doors. Reused materials are just about the most virtuous components you can select because there is no-longer and associated environmental impact.

'Envirotile' roof tiles made from recycled plastic


Use materials that feature recycled content. There are plenty of materials that can be used as part of new building components. They might come from outside of the construction industry such as slag from furnaces or aluminium from drinks containers; Equally they might be sourced from construction such as concrete crushed and recycled as new aggregate.

  • Use materials with low embodied energy (though strictly low embodied carbon).
  • Embodied energy is the amount of energy used to make a product/material.
  • Most energy is still fossil fuel based, which emits Greenhouse Gases like Carbon Dioxide. Hence Embodied Energy is more properly known as Embodied Carbon to distinguish it from Energy from Renewable Sources. In reality though, hardly anyone uses the more accurate term.
Using materials close from close to the site reduces the impact of transport Source: Johnsen Schmaling Architects



  • Transport is actually a sub-concern of Embodied Energy.
  • The issue is how much Carbon Dioxide and other gases are emitted in the process of transporting materials around the country / world.
  • To reduce the amount of fuel burnt in transportation of goods, it makes sense that where possible, building materials are sourced locally.


In a lot of instances, products and materials that are fabricated from non-food crops can offer alternatives to more conventional or fashionable materials. The aim is to move our reliance away from either materials that are made from oil (e.g. plastic) or made from minerals that are energy intensive in their production (e.g. steel) . By not doing this we can save energy and non-renewable resources that can be saved for greater needs amongst future generations.


  • Timber is the most well known and prolific of all the crops that we harvest to use as building materials. ‘Rapid Renewable’ in this case means soft-wood forests that grow quickly rather than, say, tropical hardwoods that take a long time to grow and probably involve habitat destruction.
  • Timber has a huge range of applications available for your house some of which we explore later.
  • Choose timber that has third party certification such as FSC or PEFC. Labels are printed on the timber and the packaging.


  • Social Responsibility is best known as one of the more challenging issues in the clothing industry where most products are outsourced to Third World countries. Working conditions, health and safety as well as paying for a fare return for work, continue to trip-up clothing companies relying on their products being made in environments not directly under their control.
  • Though not as obvious, some elements of the construction industry - for example importation of some tropical hardwoods, have sometime caused destruction of old forest habitats along with wildlife and the native societies depending on them. With timber certification, the issues with timber are largely being brought under control. However many electronic products including ‘white goods’ from Asia can be produced in conditions many of us would not approve of.
  • If the product is a complex mechanical / electrical piece of equipment - find out how it is disposed of.
  • An interesting exercise is to find out what happens to your PC when you dispose of it. Hint: it doesn’t go to landfill and it doesn’t go back to the computer manufacturer……
  • If you have any doubts about where and how a product is made, ask the supplier / manufacturer for more details. Don’t be fobbed off because they find it difficult to answer!
  • Big companies producing products and materials will likely have a statement regarding their Corporate Social Responsibility. Ask to read it. Is it genuine or just hot air from the marketing department?
Families including children recover metals from PCs shipped from the West



  • Renewable Energy has a very low environmental impact compared with oil, gas and nuclear.
  • Renewable Energy generation is most efficient at national level where big investments can be made into very large energy producing sites such as off-shore wind farms (and hopefully tidal in the future).
  • Producing electricity for when you need it continues to provide a technical challenge both at a national and domestic scale. Wind power isn’t power when there’s no wind. Solar electricity doesn’t really happen very much under a grey sky.
  • Producing electricity isn’t really the challenge, but electrical storage, particularly in batteries still needs a technical breakthrough. It needs to provide cheap and efficient storage to supply household appliances with electricity on demand.
  • However, on balance, it is still worth installing solar electric panels to provide electrical supply where possible.


  • Solar Electric panels used to be prohibitively expensive, but prices have plunged with the technology now primarily manufacturers in China.You can still supply electricity back into the grid when you’re not using it (a kind of ‘storage’) and get paid for it. An investment into a workable installation will pay-back over a reasonable period.
  • You’ll need 35 - 40m2 within no more than 30° deviation from a South-facing roof pitched at 35° - 40°.
  • The roof should be unshaded by trees or adjoining buildings.
  • Use the Grid as your battery supply.


  • Domestic-scale wind power once held out to be a realistic provider of electricity. However installation requires turbines that are large enough to provide a sensible supply located in a position where the approaching wind is not interrupted by obstacles.
  • Trying to mount turbines on your house is a ridiculous waste of money.
  • The most appropriate application for a small wind turbine would be in a rural location where there is an average, unobstructed wind speed of at least 6m/s.
  • The turbine will typically be mounted on a support at no less than 10m above the ground.


  • Solar thermal panels mounted on the roof are a good source of hot water. They can provide up to 70% of your annual hot water needs - of which is around 20% in winter and 100% in summer.
  • They need to be mounted on a south-facing roof of a pitch of around 30° - 40°
  • The common ‘flat panel’ technology is tried and tested and uncomplex.
  • The simplest solar panels are a bit like radiators painted black with cold water pumped through them which in turn is heated by the sun.
  • A more sophisticated design is based on the ‘evacuated tube’ technology. It is more efficient but more expensive.
  • The warmed-up water will then be returned to a storage cylinder shared with another hot water-generating appliance such as a gas or wood chip fuelled boiler.
Evacuated tube water heating technology


  • There are ‘Ground Source Heat Pumps’ (GSHP) or ‘Air Source Heat Pumps’ (ASHP).
  • Heat Pumps work like refrigerators in reverse. They take heat from either the ground or the air and ‘upgrade’ it to a higher, more useful, temperature to heat space or in some instances water.
  • Because Heat Pumps operate using electricity, you need to be certain that the heat energy you gain from the earth or air significantly exceeds the operating electrical energy. The ratio between heat gained and electricity expended is call the ‘Coefficient of Performance’ (COP).
  • You should look at getting a COP ratio of 3.0 or above. Verify with the manufacturer/supplier that their equipment achieves this ratio consistently.
  • Heat pumps should not be used to provide Domestic Hot Water (DHW) in conjunction with Electrical Immersion Heaters. The overall electricity load will be immense - effectively derailing your low energy project.


  • The Ground Source Heat Pump is a system that extracts heat from the ground, upgrades it to a higher temperature and releases it where required for space heating.
  • It is ideal where for a low energy heating system such as underfloor heating.
  • It is not effective at heating water for your hot water supply and would need to work as a ‘pre-heater’ to a storage vessel in conjunction with a gas or wood-chip boiler.
  • A GSHP system relies on the installation of a loop of pipe underground on the site surrounding the house. You need to make available a lot of space OR bore deeply vertically into the earth.
  • Ground Source Heat Pumps are at their most appropriate where the grid gas supply is unavailable.
  • A GSHP system can be expensive and require specialists to install and commission correctly for successful operation.
  • There have been plenty of commissioning disasters to date - so beware!


  • The Air Source Heat Pump is a system that extracts heat from the atmosphere and upgrades it to a higher temperature.
  • ASHPs are very much cheaper and easier to install than Ground Source
  • Historically they have had problems operating at very low outside air temperatures as they can put a heavy demand on electricity to keep running.
  • Technology is improving and it is worth bearing in mind that in Norway and Sweden, where, admittedly hydro electricity is easily available, heat pumps have been a standard heating method in houses for many years.


  • Biomass Boilers are the alternative to gas or oil fired boilers.
  • The boilers use use wood chips or pellets which are routinely available from an increasing range of suppliers.
  • The boilers are automatically fed from a hopper containing the fuel.
  • Compared with a conventional gas boiler, they’re quite expensive
  • Biomass boilers are not pollution-free, they still produce smoke and can’t be used in a smokeless zone. The Carbon Dioxide they produce has already been sequestered during tree growth - and will be re-absorbed if the trees are routinely replaced.
  • Trying to install a log-burning stove into a well-sealed, energy efficient house is not a good idea.
  • Fires (and building inspectors) need plenty of ventilation - which air-tightness works against.
  • If you have a house at or near to Passivhaus standards, you will not need the relatively massive amount of heat that a typical wood burning stove produces.


  • Climate Change is disrupting weather patterns in the UK and around the world
  • The South East of England is particularly vulnerable to Climate Change with increasing drought-inducing conditions in the summer combined with higher temperatures.
  • In the SE water tables are low and the population is dense.
  • The situation will only get worse.
  • Part G: ‘Sanitation, hot water safety and water efficiency’
  • The Regs require that ‘Reasonable provision must be made by the installation of fittings and fixed appliances that use water efficiently for the prevention of undue consumption of water’
  • The maximum water usage per person/day is set at 125 litres.
  • Local Authorities have the power to restrict this further to 110 litres if local conditions demand.
  • The water consumption per person must be demonstrated through calculation at the design stage.
  • Water usage calculators are available.
  • Choose water-efficient shower heads
  • A 5 minute shower is more water and energy efficient than a bath.
  • Choose low-flow taps..
  • Choose appliances with the best performance on the European Water Label.
  • Dish washers use much less water than sink washing - but use energy.


  • Before you start thinking about water recycling, ensure that all your appliances, wc, bath, washing machine, dishwasher are the most water-efficient available.
  • Waste water is either ‘grey’ from baths, sinks, washing machines or ‘black’ from the toilet
  • ‘Blackwater’ should be disposed of either into the sewage system or, if you’re off grid, into a septic tank that has been calculated to accommodate the needs of your family.
  • If greywater is used at all, it is most useful for flushing the toilet.
  • Unless it is treated, grey water can’t be stored for more than 24 hours.
  • Treating it takes energy, resources and storage, so it is a balanced calculation as to whether to use it or not.
  • Ask a water consultant for more information if you’re aiming to use your greywater,
  • It’s tempting to think that with plenty of rainwater, it is possible to go a long way in replacing the main supply.
  • In practice, rainwater for use within the household is costly to use both in terms of equipment required and the energy to pump it around.
  • Consider using rainwater inside the house only when nearly or all the water demand can be met.
  • The best use of rainwater is for garden irrigation (and washing your hair)..
  • Unless it is treated, grey water can’t be stored for more than 24 hours.
  • Install a water butt fed by water draining from the roof.


  • Air pollution is a feature of modern life - both outside and in.
  • Air contamination from cars and factories infiltrates our homes
  • Indoors we can suffer from emissions from building materials, furniture, cleaning products, people and pets.
  • The most important pollutants outside and in are volatile organic chemicals (VOCs), gases such as nitrogen dioxide, ozone and carbon monoxide, particulate matter and fibres, and biological particles such as bacteria, fungi and pollen.
  • Controlling indoor air quality depends on limiting emissions from materials and products alongside providing clean fresh air.
  • The traditional method of reducing and eliminating indoor air pollution is through natural ventilation - such as opening windows to let fresh air in. However, with increasing standards of air tightness, houses are becoming a lot less natural ventilated.
  • When air tightness gets towards the standard that Passivhaus recommends (much more stringent than Building Regulations) there becomes a need for mechanical ventilation.
  • The best system is Mechanical Ventilation with Heat Recovery (MVHR). This is a systems of ducts which run around the house collecting foul air and delivering fresh air. At the centre of it all is the ventilation unit which collects the air from the house and pumps it to the outside while drawing in fresh air which is filtered and pumped into the ducts. The Heat Recovery comes in the unit where the warm air going out effectively heats the cooler air coming in. The result is that the house receives fresh and clean warmed air. It is relatively expensive but essential when reaching the very high standards of energy conservation.
  • Many of these problems can be solved by careful selection of the building materials you use in your house - primarily paint and floor finishes.
  • Floors: Avoid carpeting. Fitted wool or nylon carpets contain a high number of pollutants and irritants such as flaked-skin and mites. Carpets are particularly bad for asthma sufferers.
  • Floors: If needed, substitute carpeting from a range of vegetable products such as jute, sisal or coir matting thrown over solid floor finishes.
  • Floors: Choose tongue & groove (T&G) timber floor finishes to avoid adhesives; or tiles, rubber or linoleum, stone, bamboo or cork.
  • Floors: Avoid vinyl flooring(PVC).
  • Avoid using timber particle boards, fibre board, plywood, with formaldehyde content where exposed to the indoor atmosphere. These can be found both in building and furniture components.
  • Walls: Use plaster rather than plasterboard if possible.
  • Walls: Low VOC Paint e.g. water based acryilcs.
  • Walls: Try and use paint with low or no Titanium Dioxide. It is a mineral that is polluting throughout its extraction and manufacturing process.
  • Uncontrolled condensation promotes fungal growth and fabric damage.
  • Condensation occurs when moist warm air meets with a cold material. The most common experience for most people is waking up in the morning with water running down the window glass.
  • People and animals produce warm moist air all the time through breathing so naturally a room like a bedroom can build-up a lot of moisture overnight.
  • Other common activities such as cooking, washing, bathing and drying laundry generate moist air.
  • Always ensure that bathrooms and kitchens are well-ventilated.
  • Tightly air-sealed houses will present the greater challenge where less incidental ventilation (through cracks, holes etc in the walls and roof) is available
  • In an energy-efficient, tightly sealed house, particular attention must be paid to ensuring sufficient ventilation to prevent moisture build-up and reduce the chance of condensation occurring.
  • Installing a ‘whole house’ ventilation system will obviate most air moisture issues as well as background odours.
  • Keeping your house at an even temperature will prevent air cooling and condensation occurring.
  • Consider a ‘breathing wall’. Breathing walls consist of materials that can absorb and expel moisture as the internal air humidity changes. The walls don’t ‘breath air’ as much as moisture. Not everyone is a fan of this way of dealing with moisture, but it is worth thinking about.
  • Our health depends on regular exposure to light and dark each day. (Vitamin D and our circadian rhythms of waking and sleeping)
  • Daylight is the most effective way of providing light.
  • Too much light can be uncomfortable.
  • A view of the outdoors is a contributor to wellbeing.
  • Effectively using daylight to light your home is a delicate balance against the effects of windows on the overall energy used by the house.
  • Choose an LED-based lighting system.
  • Unless for security reasons, don’t install lights for the external lighting of the house or other features. External lighting wastes energy and contributes to overall levels of light pollution at night.
  • Noise is unwanted sound.
  • At high levels it can be hazardous to health.
  • Repeated noise can cause severe stress.
  • A well-insulated house with high-performance windows will significantly reduced noise from the outside.
  • Building Regulations Part E addresses sound insulation.
  • Impact Sound (e.g. footsteps) is transmitted through the building structure.
  • Airborne Sound (e.g. talking or TV) is transmitted through the air.
  • Part E sets minimum standards of airborne and impact sound transmissions both from adjoining houses (e.g. terrace housing) and between rooms inside a house