There has been talk in the news recently about the standards for houses to meet ‘low carbon’ requirements.
Developers say it will cost £30,000 to meet the 2016 ‘zero carbon’ standard. Although it is also said the cost is overstated and the effect understated. It would be interesting to see a breakdown of this cost as newly fitted thicker insulation and efficient boilers probably don’t cost a lot more. So there must be some big cost drivers to be exposed.
Below I’ve found some examples of what it might entail. It seems only the self generating capacity is a significant new cost. The cost of this would come down if it became widespread. Also local areas could install their own systems to reduce costs.
Then there is the forecast cost of fuel. There are websites saying energy costs could reach £5000 a year if price increases over the last few years continue. Obviously this depends on the dates you pick and maybe if you picked the last 12 months then energy costs could be forecast to be zero in 20 years. So what is a reasonable figure?
A lot depends on cost effectiveness as we can’t spend limitlessly on the assumption of global warming. For example if we insulate and the temperature goes up then maybe we don’t need it. If it rains all the time then maybe solar power won’t do much good. Wind seems probable, etc. Is any of this based on metereological data and reasonable assumptions?
I’ve a lot to find out to be convinced, particularly being wary of who is presenting what figures and why. Although in general I support minimising human effect on the environment for whatever purpose if it creates a better Earth for everything on it.
The government issued a paper on house standards, dated 2006. It uses code levels to cover the standard.
Level 1 is slightly better than todays regulations. An example of what might meet the standard;
The home will have to be 10% more energy efficient than one built to the 2006 Building Regulations standards. This could be achieved by:
• Improving the thermal efficiency of the walls, windows, and roof (by using more insulation or better glass for example);
• Reducing air permeability, that is by improving the control of the fresh air into a home, and the stale air out of a home. (A certain amount of air ventilation is needed in a home for health reasons);
• Installing a high efficiency condensing boiler;
• Carefully designing the fabric of the home to reduce thermal bridging (thermal bridging allows heat to easily escape between the inner walls and the outer walls of a home).
The home will have to be designed to use no more than about 120 litres of water per person per day. This could be achieved by fitting a number of items such as:
• 6/4 Dual Flush WC;
• Flow Reducing/Aerating taps throughout;
• 6-9 litres per minute shower (note that an average electric shower is about 6/7 litres per minute;
• 18ltr maximum volume dishwasher;
• 60ltr maximum volume washing machine.
Other minimum requirements are required for:
• Surface water management – this may mean the provision of soakaways and areas of porous paving;
• Materials – this means a minimum number of materials meeting at least a ‘D’ grade in the Building Research Establishment’s Green Guide (the scale goes from A+ to E);
• Waste management – this means having a site waste management plan in place during the home’s construction, and adequate space for waste storage during its use.
But to get to Level 1 you need a further 33.3 points. So the builder/developer must do other things to obtain the other points such as:
• Providing accessible drying space (so that tumble dryers need not be used);
• Providing more energy efficient lighting (taking into account the needs of disabled people with visual impairments);
• Providing cycle storage;
• Providing a room that can be easily set up as a home office;
• Reducing the amount of water than runs off the site into the storm drains;
• Using environmentally friendly materials;
• Providing recycling capacity either inside or outside the home.
Level 6 Example of a Carbon Neutral house for 2016;
The home meeting any level of the Code will have to meet minimum standards for certain items depending on what Level is desired. For Level 6 this means:
The home will have to be completely zero carbon (i.e. zero net emissions of carbon dioxide (CO2) from all energy use in the home). This could be achieved by:
• Improving the thermal efficiency of the walls, windows, and roof as far as is practically possible (by using more insulation or better glass for example);
• Reducing air permeability to the minimum consistent with health requirements (a certain amount of air ventilation is needed in a home for health reasons);
• Installing a high efficiency condensing boiler, or being on a district heating system;
• Carefully designing the fabric of the home to reduce thermal bridging (thermal bridging allows heat to easily escape between the inner walls and the outer walls of a home);
• Using low and zero carbon technologies such as solar thermal panels, biomass boilers, wind turbines, and combined heat and power systems (CHP). It would mean for example that energy taken from the national grid would have to be replaced by low or zero carbon generated energy, so that over a year the net emissions were zero.
The home will have to be designed to use no more than about 80 litres of water per person per day. This could be achieved by fitting such items as:
• 6/4 Dual Flush WC;
• Flow Reducing/Aerating taps throughout;
• 6-9 litres per minute shower (note that an average electric shower is about 6/7 litres per minute);
• a smaller, shaped bath – still long enough to lie down in, but less water required to fill it to a level consistent with personal comfort;
• 18ltr maximum volume dishwasher;
• 60ltr maximum volume washing machine.
To achieve the standard would also mean that about 30% of the water requirement of the home was provided from non-potable sources such as rainwater harvesting systems or grey water recycling systems.
Other minimum requirements are required for:
• Surface water management – this may mean the provision of soakaways and areas of porous paving;
• Materials – this means a minimum number of materials meeting at least a ‘D’ grade in the Building Research Establishment’s Green Guide (the scale goes from A+ to E);
• Waste management – this means having a site waste management plan in place during the home’s construction, and adequate space for waste storage during its use.
But to get to Level 6 you need a further 64.9 points. So the builder/developer must do many other things to obtain the other points. In fact they will need to do 90% of everything in the
Code to achieve Level 6, including:
• Energy efficient appliances, and lighting;
• Supplying accessible water butts;
• Reducing surface water run-off as much as possible;
• Using highly environmentally friendly materials;
• Minimising construction waste;
• Maximum, accessible provision for recycling;
• Improved daylighting, sound insulation and security;
• Building to the Lifetime Homes standard;
• Assessing and minimising the ecological impact of the construction of the home.
Is the above Good or Bad?
With the exception of generating power there is nothing there that looks particularly taxing. I’m not sure what grade D materials are though. In general I support it but want to watch the costs.
Retrofitting a lot of the existing housing will be a big challenge and the use of home generating sounds idealistic. I’d assume that localities could take it in their own hands to set up local power generators. Also windows and walls could be expensive to replace before they are worn and maybe there is no economic case for doing this unless energy prices increase significantly. One council fitted external cladding to houses at a cost of £4000 to £6000 a house. There are about 25 million dwellings in the UK and only about 100,000 are being built at present so the new standards will take a very long time to have any effect if they are restricted to new build.
The 2006 code for sustainable homes is on the link below.
http://www.planningportal.gov.uk/uploads/code_for_sust_homes.pdf