a very low energy house at Peterculter

There are now several sets of standards afoot, and it can be quite confusing because they have somewhat different approaches. more +/-»

The Building Regs, part L

Currently there is a transition period for part LThe Building RegulationsThese are the legal regulations which govern how a house is constructed. (not to be confused with Planning Permission which is about whether you are allowed to build the house at all or what it might look like) see Building Regulations), part L is the section which covers energy conservation for new buildings (with part L1A covering new buildings and part L1B covering existing ones) and there is a good explanation of the latest changes is published by the NHBCThe National House-Building Council describes itself as being "the leading warranty and insurance provider and standards setter for UK house-building for new and newly converted homes" as a Technical Extra

Part L (which are the current mandatory legal standards) has been tightened  as regards thermal insulation and new standards to do with air tightness are being ushered in, though more slowly, and with some resistance from the mainstream building industry. They are likely to be improved considerably over the next decade or so.

A SAPStandard Assessment Procedure - the method used in the building regulations for calculating the energy use of a house. see Part L and SAP ( Standard Assessment Procedure) rating is required under the building regulations (Part L (England and Wales), Section 6 (Scotland) and Part F (Northern Ireland). SAP is an energy rating which estimates the annual space and water heating energy use of a house.

The 2009 edition of the Standard Assessment Procedure (SAP 2009) will be introduced from October 2010 and will be used for compliance with building regulations in England & Wales (Part L) and in Scotland (Section 6) and for the generation of Energy Performance Certificates for new dwellings. Similar provisions will be made in Northern Ireland at a later date. The actual SAP calculation details are available here

Code for Sustainable Homes

The old Ecohomes scheme is due to expire on the 8th of April 2012 and be superceeded by the CSH which is part of BREEAMBuilding Research Establishment Environmental Assessment Method. See Green Design Standards . It is an interesting but slightly strange way into the process of ecological house design. It’s a check list of how green the design is likely to be with a simple scoring system for each part. It covers -

• Energy efficiency/CO2Carbon dioxide is a gas which is given off when carbon based materials such as fossil fuels (coal, oil, and natural gas) are burned. It is called a greenhouse gas because it works like the glazing of a greenhouse and causes global warming – see Energy
• Water efficiency – see Water conservation
• Materials – see Building materials
• Surface water management – see Surface rainwater and SUDSSustainable urban drainage systems. Various ways of holding back rain water and allowing it to percolate into the ground instead of taking it to a drain and sewer. This helps prevent flash flooding. See Surface rainwater and SUDS
• Site waste management
• Pollution – see Avoiding pollution
• Health and wellbeing – see Health issues
• Management of the construction – see Job management
• Ecology –  see  Habitat protection

The best place to get an idea of how this works is the Code for Sustainable Homes: Technical guide – 2010. There you can download a large PDF containing the actual guidance. There is a useful FAQ there which you can download as an Excel file.

Since 1 May 2008 it has been mandatory for all new homes to have a rating against the Code (even if it is only a zero rating).  However CSH is a strange animal in that it allows you to pick up points on some issues at the expense of points on others, – a real mixed bag rather than a pure standard. So for instance you can forsake a bit of energy efficiency provided you have recycling facilities etc.

According to a BREEAM press release of  20/3/12 there are now “a record number of new and existing buildings being registered for BREEAM assessment“. Some local councils are now insisting on houses being designed to CSH level 4 or sometimes level 3 as a condition of planning permissionthe legal basis for being allowed to do some form of development such as building a house. (not to be confused with Building Regulations which is all about whether the building is properly constructed). see more on Planning Permission .

BREEAM have recently published on line their manual for assessing refurbishment work.

Extra cost of building to CSH 

The CSH Cost Review is a very detailed document published by Communities and Local Government which considers the extra cost implications concerned with building to the various levels of the Code for Sustainable Homes. It is mainly aimed at developers but has a huge amount of information that may be of use to the green self builder. When it was published (in 2010), there was very little firm information to go on as the report points out

“Despite the plans of many developers to build Code homes, at the time of the research the number of post-construction certificates (certifying Code homes) stood at a relatively modest figure at around 40″

It is interesting to note that nearly all public housing such as that for housing associations must already conform to CSH level 3 which is 25% better than current building regulations in terms of energy. This is considerably better than most private builders achieve and in not so long it may be increased to level 4.

Also with existing houses the code is a useful means of assessing the green aspects of a house. Unlike the other standards around, Ecohomes standards are not just to do with energy usage but cover a whole lot of other green issues. There is a guide to the likely score achieved. The standard has however come under considerable criticism because of the way it treats how the primary heat source for dwellings is factored in to the calculations. There is a technical guide here

Zero carbon ?

The government has stated that all new homes shall be ‘zero carbon’ starting from 2016. This is based on a general European move towards zero energy building by 2020. This equates to CSH level 6 in terms of energy use which is an extremely high standard and will require the whole house building industry, at all levels, to reinvent itself, considering that at present (2012) there are only a handful of zero carbon homes in the country and considering also the lamentable skill level and generally low culture of care and thoroughness within the industry. The definition of zero carbon is on the Zero Carbon Hub web site and was quite controversial because it is aimed at only the building itself and does not generally include the appliances within it.   See the WWF article “Why we’ve resigned from the Zero Carbon Taskforce” and also the Zero Carbon Hub web site

Whether the country has the facilities or even the will to retrain the building industry to move from Neanderthal to rocket science in a few years is very questionable. To give an example – practically no plumbing courses at any of the colleges of building in the UK ever take their students out to look at a solar collector installation, let alone teach them how to plumb one up. However some of the more forward looking house designers and architects are busy getting to grips with the challenge and producing solutions, e.g. Ruralzed

It is intended that ‘zero energy’ will be phased in through a number of CSH stages

• 2013 level 4 (44% better than current regulations and almost up to PassivhausSee more on the Passivhaus standard. The PassivHaus Institute has pioneered a standard for low energy buildings. It includes very low energy usage and ways of achieving this. The word is derived from the idea of buildings which are fundamentally low energy and passive solar heated rather than using extra gadgets to heat them. See Passivhaus for the UK branch of the organisation. standard)
• 2016 level 5 (zero carbon for heating and lighting),
• 2016 level 6 (zero carbon for all uses and appliances

The government has recently restated its commitment to zero carbon and introduced the concept of  ‘Allowable solutions’

Passivhaus standard

See more on the Passivhaus standard

Passivhaus is an extremely high standard of building developed in Germany and Sweden and aimed at producing very low energy usage. There are now many thousand houses, mainly on the continent which have been built to the standard over the last decade or so. It relies on:

• Very high amounts of insulation.
• Awesome levels of draught proofing and air tightness.
• High levels of air quality
• Heating mainly from passive solar.
• Heat recovery from whole house mechanical ventilation.

Interestingly the heating load is so low that a central heating system is not required (with the consequent cost savings of maybe £4000 – £5000). A very small amount of heat is injected into the ventilation system electrically (or via a ground source heat pump driven electrically) and for the occasional very low winter temperatures experienced in some parts of Northern Europe a small stove may be included in one room.

This type of low energy building is not intrinsically expensive but takes a degree of skill and care which is almost impossible to achieve with the present cultural attitudes towards house building prevalent in the UK.

Design software is available from the Passivhaus Trust and BREBuilding Research Establishment. and the Passivhaus Trust itself is running courses about how Passivhaus works.

There is a recently produced design manual and Planning Package from the Passivhaus Institute. These design tools are based on robust and practical ways of designing a building rather than the more theoretical calculation methods used by the Code for Sustainable Homes (above).

There is a big question as to whether the Passivhaus approach might be more sensible than the government’s stated intention of going for ‘zero energy’ homes. Whereas zero energy is a higher standard than Passivhaus, it is debatable whether zero energy is practicably achievable within the UK context (except for a small minority of extremely dedicated builders) whereas Passivhaus is now a mainstream and well proven standard across Europe.

Passivhaus standard is only about energy and has nothing to say about other aspects of sustainability such as the health issues of building materials (these are mainly dealt with separately on the continent).

As yet there has only been a very few houses built in the UK which has been certified as reaching the Passivhaus standard.

Your architect or designer should be conversant with these standards and be able to advise you on the latest developments.

More about Passivhaus standard

The state of play in Europe regarding low energy building is outlined in an EU article called LOW ENERGY BUILDINGS IN EUROPE: CURRENT STATE OF PLAY, DEFINITIONS AND BEST PRACTICE

The AECB silver and gold standards

AECB standards set up by the Sustainable Building Association under their CarbonLite Programme. These include the Silver standard, the Gold standard and an endorsement of the Passivhaus standard and how it relates to the other two. Excellently put together with lots of example on their web site.

If you are a member of the AECB you can get extensive free downloads covering Passivhaus Construction Guidance. There is a resume of the guidance on the Simmonds Mills web site

The Energy Performance Certificate

The EPCenergy performance certificate is what you will need to provide if you sell your house or rent it out. It is an assessment of how well your house performs in terms of energy use. There is still considerable disagreement about how well this system of measurement works but it is now in operation.