The government is looking for responses from the heating industry, consumers and those with a wider interest in the UK’s net zero ambition to help shape the design of the policy. Please feel free to provide your response to the consultation questions here. The closing date for the consultation is 12th January 2022.
Net-Zero is an ambitious target for governments, companies and institutions to dramatically reduce environmental impact and to prevent the most damaging effects of climate change. Significant cuts in emissions across the built environment are required in achieving this goal.
At CBG Consultants Ltd, we create buildings that minimise their environmental impact. We have a wealth of experience in thermal modelling which enables us to understand the performance of a building through a computer-generated model to assess energy consumption and carbon emissions.
Understanding how buildings generates carbon emissions and the predicted impacts of various measures and strategies through detailed modelling will generate a robust route map to Net Zero Carbon.
Remember, it’s up to us all to fix this climate crisis. Take your first step by visiting WWF’s carbon calculator to understand your carbon footprint and take actions.
The New London Plan 2021
After more than three years in the consultation process, the New London Plan came into force on 2nd March 2021.
The Plan sets the overarching framework for how London will develop over the next 20-25 years. It gives focus on new developments and redevelopments to meet low carbon, energy efficiency and sustainability standards as part of a drive to make London a zero-carbon city by 2050.
Our team have extensive experience supporting projects through the planning process on major London schemes and advising on the policy requirements. We can provide a full range of MEP and sustainability services in all areas of the built environment.
For information on the adopted changes and how they may affect your project, please get in touch!
The advice is a reduction in UK greenhouse gas emissions of 78% by 2035 relative to 1990. This would achieve well over half of the emissions reduction required by 2050 in the next 15 years. The analysis in the report shows this is feasible, provided effective policies are introduced across the economy without delay. The budget requires a major investment programme, worth around £50 billion each year from 2030 to 2050. However, the CCC estimates net costs of meeting the budget to be low, equivalent to less than 1% of GDP.
The report covers every section of the economy including buildings. Specific actions for the buildings sector include:
Reducing demand for carbon-intensive activities such as increased insulation and low-energy appliances.
Take-up of low-carbon solutions. The CCC expects this will largely be in the form of switching from fossil fuels boilers to electric solutions such as heat pumps. For example it recommends that the sales of residential gas boilers should be phased by 2033.
Expansion of low-carbon energy supplies. There are two key areas for this: low-carbon electricity, largely from off-shore wind, and low-carbon hydrogen which can used in sectors less suited to electrification.
To make all buildings energy efficient and ultimately low-carbon a clear timetable for policy standards is needed along with industry changes to rapidly scale up supply chains for heat pumps and to develop the option of hydrogen for heat.
CBG applies these principles with a ‘fabric first’ approach to reduce energy demands by focusing on passive design. Then it is followed by the design of efficient buildings services.
We keep up to date with all building regulations and policy guidance and can provide CPD presentations to assist with the transition to low and zero-carbon buildings. Please do contact us to schedule a CPD for your team.
Minimum Energy Efficiency Standard (MEES)
The Minimum Energy Efficiency Standard (MEES) came into force in England and Wales in April 2018, these standards apply to private rented residential and non-domestic properties.
The aim of the MEES is to encourage landlords and property owners to improve the energy efficiency of their properties by upgrading fabric, installing new boilers and energy efficient lighting etc.
Properties with EPC ratings of E or less will be subject to restriction on the granting and continuation of the existing tenancies .
Minimum Energy Efficiency Standards (MEES) applies to any privately rented property which are legally required to have Energy Performance Certificate (EPC), these include assured short hold, regulated and domestic agricultural tenancies. From April 2018, landlords will not be able to grant a tenancy to new or existing tenants with an EPC rating of F and G and from 1 April 2020, they’ll not be able to continue letting the property without improvements.
Landlords are not expected to finance the cost of improvements but to use third party resources such as Green Deal and Local authority improvement grants. Exemption can be claimed where they are not able to get the funding/grant to cover the cost of the improvements, or are not able to achieve the minimum EPC rating (E) even after improvements. Any exemption must be registered on the RPS Exemption Register.
Non-Domestic Private Rented Property
Similarly, as above from 1 April 2018, non domestic landlords must not grant new tenancies without the minimum energy efficiency standards. They cannot continue to let the property after 1 April 2023 where property has an EPC rating of below E.
All the improvements to Non-Domestic properties will be funded by landlord or tenant, there is no third-party funding available. Landlords may be able to claim exemption, all exemptions must be registered on the RPS Exemption Register.
We have a team of Qualified Level 3, 4 and 5 Energy Assessors, who can provide assistance with MEES compliance and provide advise on how to achieve MEES compliant building. Please do contact us should you wish to find out more.
A Sunny Afternoon in Oxford!
Always seeking an excuse to take a sunny walk in Oxford, Chris Dicks took time out between meetings for a stroll around the Thames and Christ Church Meadows, to look at a few current and former CBG Consultants Oxford projects.
First stop was the Cathedral at Christ Church, where we are nearing completion of the first phase of the new lighting project. Working with Purcell, Monard Electrical, and specialist designers, the project sees the replacement of energy hungry and failure prone halogen lights with high performance LEDs.
The next stop was our project completed with A2 Dominion and Yurky Cross, at Thames Street. Completed around 2015, this £8M project comprised of four residential blocks, with a mixture of social housing and student accommodation.
Continuing on the Thames waterfront, Chris checked in on our refurbishment project at Christ Church’s Boat House. Working with Robert Montgomery Architects, new changing facilities, gym, workshops, punt store and kitchen are being provided. Then it was on to the Jubilee Bridge, where CBG assisted Christ Church with infrastructure services to this elegant new footbridge, opened by the Dean in 2014.
After a pleasant walk through the Meadows, Chris reached the famous Broadwalk, along the sunny south site of Christ Church. We have worked on several major refurbishment projects with Sidleys Chartered Surveyors in the Meadows buildings over the years, including the main visitor entrance.
Finally, it was back to the iconic Tom Tower on St Aldates, housing the famous Old Tom bell. In 2011, CBG worked with the college to locate new hot water distribution plant within a spare corner of the tower, which was last open to the public in the 1930s.
Just time for a quick coffee at another Oxford institution G&D’s café, then on to the next meeting…
BREEAM UK New Construction 2018, So What’s New?
On Friday 23rd March 2018, the BREEAM UK New Construction 2014 scheme will close for registration and usher in the new era of BREEAM UK New Construction 2018.
Released on the 7th March, this new scheme looks to upgrade on BREEAM UK NC 2014, to improve the clarity of the technical manual for all users and give an added focus to the building’s life cycle in an overall more concise manner.
We have reviewed the new manual and below are a few of the major developments made by the BRE in BREEAM UK New Construction 2018:
Post-Occupancy Stage (POS)
The biggest development is the introduction of a new Post-Occupancy Stage, an optional third stage. This assists in assuring that the design performance targets are being monitored and reported to identify any deficiencies in performance and where required rectify; focusing primarily on the Energy and Water categories.
MAN 03 Responsible Construction Practices
Previously, this awarded two credits if a developer adopted a Considerate Constructor’s Scheme and achieved a score >35.
BREEAM UK New Construction 2018 has replaced this requirement with a checklist of 19 responsible construction management items of their own, although many of these can be covered by undertaking a compliant CCS.
Updating on the BREEAM NC 2014 manual, there is now a requirement not just to monitor energy use, water consumption and transportation data on site, but to also to set performance targets.
The Transport Category has had a complete facelift. Four credits have now been compacted into two; the first is awarded by producing a Travel Plan, which has had its own criteria update and the second has become an amalgamation of all the previous Transport credits from BREEAM NC 2014. A selection of 11 transport measures are provided, with credits awarded based on how many are implemented on site.
ENE 01 Reduction of Energy Use and Carbon Emissions
Previously the energy performance ratio (EPRNC) section of this awarded 12 credits, rewarding reduction in building energy use. However, this has now been reduced to 9 credits with a reduction in the size of the benchmark scale, whilst keeping the EPRNC score minimum standards for overall BREEAM ratings. This change has been introduced to encourage the uptake of the 4 new credits to encourages additional modelling and reporting energy consumption data.
MAT 01 Environmental Impacts from Construction Products – Building Life Cycle Assessment (LCA)
The major change in Mat01 is the removal of the Green Guide ratings, in its place is the BRE’s Life Cycle Assessment tool. This tool now includes the ranges of elemental descriptions previously found in the Green Guide, and will ultimately calculate the credits awarded.
Another option is the IMPACT Compliant LCA tool, which has a similar process but is integrated into BIM or IES software.
Furthermore, the BREEAM UK NC 2014, hard landscaping and insulation credits have been encompassed into the Mat01 assessment.
If you require any other guidance on the new 2018 manual or wish to speak to us regarding any potential projects that may incorporate BREEAM NC 2018, please do not hesitate to contact us.
Closing the Performance Gap in Non-residential buildings
There is an increasing awareness in the construction industry that buildings do not perform as expected in terms of energy and carbon emissions, an issue which has become known as the “performance gap”.
For example, in a recent study by Innovate UK, it was shown across a range of non-domestic buildings that carbon emissions were 3.8 times high than design estimates, and that energy use varied widely. There are a range of possible causes for the performance gap in buildings. Here we outline a number of issues we have experienced and how they may be overcome in the design and construction of buildings.
For most new buildings a computer model will be produced to demonstrate compliance with Part L of the building regulations. This involves the use of approved software which calculates the carbon emissions of the building, which must be less than or equal to a target generated by the software. This provides a means of checking compliance with building regulations, but is problematic for predicting actual building energy consumption and emissions. The models contain many generic (and unalterable) assumptions about the building use and internal heat gains, and often simplistic methods of calculating system performance. We often find that models will predict heating demands lower than Passivhaus buildings, when we know the real building demand could be more than five times this amount.
Building-specific energy modelling is needed to be able to reasonably estimate building performance. The modelling must take into account the specifics of building use, appliances, fabric and building services performance. However, like all models, the accuracy of the results is limited by unknowns. Calculating lighting energy use, for example, is relatively straightforward, whereas predicting vending machine energy performance may turn out to be a wild goose chase! Some other areas of uncertainty, like the impact of thermal bypass in insulation, or thermal bridging, are discussed further below. Where uncertainties are identified, it is useful to identify the potential impact through sensitivity tests.
A key feature of the Passivhaus approach is that many uncertainties are simply designed out or eliminated by careful construction. Not surprisingly, Passivhaus buildings can be successfully modelled using an excel spreadsheet.
Insulation & Thermal Bypass
The energy performance of building elements such as walls is calculated by reference to the “U-value”, which describes the amount of heat passing through 1m2 of surface. This value is theoretical, and assumes that the insulation has been fitted perfectly over the element. Thermal bypass describes a number of mechanisms by which heat can bypass the insulation layer, and results from imperfections in the installation. Additional heat loss is created when there are gaps between insulation boards or behind insulation boards, or in the worst-case scenario, both.
Some specific examples include;
Poorly cut or fitted insulation boards, resulting in gaps
Mortar snots in masonry walls, resulting in gaps behind the insulation
Fixings and brackets in the insulation layer which prevent insulation boards being laid flat
Unsealed party wall cavities
The effect of thermal bypass can be significant- potentially resulting in heat losses being triple what was calculated. In many cases the effect cannot be quantified- so it is best to avoid as far as possible.
How can thermal bypass be avoided?
Where possible use flexible insulation products which when fitted tightly will compress and expand to fill gaps.
Design for air-tight and wind-tight construction- preventing air movement greatly reduces transfer of heat.
Simplify junction details to make fitting insulation easier- avoid difficult angles and kinks in the thermal line
Robust specifications for installation quality (see below)
Training of installers to understand the issue
Development of installation methods for each type of insulation product
Cutting tools suitable for the insulation type
Site monitoring of insulation fitting
Thermography to spot problems (although it’s normally too late by this point).
Thermal bypass Examples: Left: Gaps between insulation boards allow air and heat to bypass the insulation layer. Right: insulation boards not joined at the corner resulting in thermal bypass. Gap behind board on left will also allow air circulation.
In non-residential developments, thermal bridging is rarely given attention, despite building regulations requirements for “continuous insulation”, calculations of junction heat losses, and a system for site inspections. In practice, the impact of thermal bridging is largely ignored, with only a nominal allowance made for it in the energy model.
The impact of thermal bridging becomes more significant for building’s with high levels of insulation, which would include buildings constructed to the latest Part L2A standards. Based on a simple 5x5m ground floor room, we calculated that with high levels of insulation, heat loss from thermal bridges could account for 28% of the total for the space, and therefore not considering them could result in underestimating the heat demand by 39%.
As well as increasing energy consumption, thermal bridges also create cold surfaces which can result in condensation forming internally, or within the fabric. Internal dampness creates ideal conditions for mould growth, with the associated health effects on occupants.
How can thermal bridging be reduced?
We would take a ‘eliminate, reduce, calculate’ approach. Where possible, thermal bridging should be eliminated by ensuring insulation continuity (a building regs requirement!). Where thermal bridging is inevitable, try to achieve some measure of insulation, or use thermal breaks. Where thermal bridges remain, their effect should be calculated using numerical modelling to generate a φ-values which can be fed into the energy model.
As a rule of thumb, a thermal bridge can be ignored if two thirds of the insulation thickness is maintained.
For steel structures, structural elements should be kept on the warm side of the insulation (and generally the air barrier too). The conductivity of metal is over a thousand times that of insulation, and if penetration through the insulation layer will greatly increase heat losses.
Glazing should ideally positioned in the middle of the insulation layer.
Window and door heads should be detailed to minimise bridging (e.g., thermally broken lintels).
Consider using timber for structural elements instead of steel. Timber is much less conductive than metal, and can be formed into insulated cassettes e.g., to construct a parapet.
Simplify the thermal line. Overhangs or external shading could be supported independently of the internal structure to avoid bridging the insulation layer.
Where structural zones are insulated (e.g., timber frames, or steel SFS systems), additional elements (fixings, studs, noggins etc) may be installed that are not shown on the drawing, increasing thermal bridging. Better to be pesimistic, or to avoid insulating structural zones!
Avoid complex 3-dimensional thermal bridges! These require specialist software to analyse and much better to eliminate the bridge.
Cladding fixings and wall ties can add significant heat loss. Lower heat loss products are available such as basalt wall ties, or thermally broken brackets.
Heat losses for a 5x5m ground floor room, for different insulation standards. Thermal bridge heat losses based SBEM technical manual.
Results from a numerical thermal model of a ground to wall junction. Colours show the temperature through the junction.
Thermal bridging examples. Left: heat loss through the lintel above the window. Right: heat loss under the external walls around the perimeter of a building.
Controls for mechanical systems and lighting, if set up correctly, are vital for minimising building energy consumption, by providing energy-consuming services only when needed. Control strategies such as weather compensation of boilers, or free cooling in ventilation systems, can reduce energy consumption by optimising the operation of the plant itself.
However, it is tempting for services engineers to push for increasing levels of complexity in control systems, in pursuit of greater and greater energy savings. In reality such complexity is more likely to lead to poor performance, as the chances of set up problems increases, and the end user is left with a system they can neither understand or operate correctly. A balance is needed between simplicity and sophistication, which will be different for each project and application.
Some key questions to ask might be;
Can standard control strategies be used rather than complex bespoke ones?
What are the big energy consumers in the building and how can the controls reduce these?
Do the energy savings justify the complexity (and cost) of the controls?
What level of expertise does the client have to operate the control system?
Would providing packaged controls with each plant item be a more appropriate than a full BMS?
Has the appropriate level of user control been provided?
Has sufficient monitoring been provided to identify issues?
It is tempting to add increasing complexity to control systems to squeeze out as much energy reduction as possible, but the reality might be very different. As complexity increases, so does the chance of errors in design, setup, commissioning, and operation, which inadvertently increase energy consumption.
Data, data, data
It takes time in new buildings to optimise performance in terms of energy and environmental control, as well as flushing out latent defects. The availability of data from a BMS system is crucial for first quantifying performance issues and defects, and then monitoring subsequent improvements.
To provide such data, the BMS must be set up to log the required parameters, and then to store the data somewhere. Normally the BMS hardware itself will have limited storage capacity, so a suitable location on a server or PC hard drive must be found. Once data is obtained it must be analysed and compared against expectations to build a clear picture of the issues.
 – Approved document L2A, 2013.
See the Service page for more information on how we can help you design buildings and optimise them for comfort and energy efficiency.
The Price of Thermal Bridging
Thermal Bridging calculations can be the most cost effective way of reducing domestic carbon emissions.
What is Thermal Bridging
Thermal bridging refers to an area of a building that has a higher heat transfer than surrounding materials. These bridges often occur at junctions between elements, for example around a window. The resulting heat losses are captured by ψ-values, which are applied over the length of each junction.
How to Design for Thermal Bridging
The effect of thermal bridges can be mitigated with appropriately placed insulating materials. One approach is to follow standard details such as the BRE Accredited Construction Details. Where standard details are not used, thermal bridging calculations are required to assess the junction performance.
The bar chart shows the capital cost of these measures per tonne of carbon saved.
The cost of offset payments used in the London Plan has also been included.
In this example, use of thermal bridging calculations was by far the most cost-effective way of reducing the carbon emissions.
Ongoing Cost Savings
The solar PV system on this project was expected to pay for itself in around 19 years (accounting for export and feed in tariff payments). However when compared to carbon offsetting this reduces to around 12 years.
Assuming a base case of poor thermal bridge design (as represented by ‘default’ thermal bridging in SAP), reduced fuel bills from improved thermal design should very quickly recoup the money invested. These measures will also last the lifetime of the building, where as other technologies (such as solar PV) have a more limited service life.
Making a carbon offset payment will never give anything back so the investment stays flat.
The use of standard construction details, or thermal bridging calculations, can provide very large carbon reductions in SAP assessments. This can result in a very cost effective route to compliance.
Thermal bridging is particularly important for projects which fall under the London Plan 35% carbon reduction target.
Significant ongoing cost savings may also be realised with good thermal bridge design.
Lux Live 2017 – CBG Selected Picks
The Lux Live lighting show is now a firm fixture in the calendar each autumn. This year’s show brought a fresh focus on connected lighting systems, the Internet of Things and intelligent controls.
But of course much of the show is given over to lighting products themselves, with a chance to catch up with suppliers and see what’s new for 2018. There are also lots of seminars and panel discussions, covering everything from emergency lighting compliance through to the convergence of lighting and data communications. CBG visited both days, some of our top picks are listed below, in no particular order:
Linea Light. Italian based manufacturer, with a much increased presence in the UK in the past few years. A great range of products, including many very small options for spots, sold under their iLED brand. Used extensively in CBG’s Pipers Corner Arts Centre project, delivering a superb calibre of light.
Hard to miss at a prime spot in the entrance, Holophane have a deserved reputation in external and sports hall lighting. They demonstrated a virtual reality (VR) console, allowing you to “stand” in a sports hall and compare different ways of lighting it, using a BIM model. A great way to show clients how a scheme will look, and something we’ll be exploring more ourselves in 2018.
Illuma. Great range of track lighting systems and spot lights, to suit all budgets. Recently used by CBG on our completed Norris Museum project for art gallery lighting. Recent additions to the range include the Probeam, an adjustable beam angle spot complete with on-board dimming. A good option for spaces where lighting needs to be regularly re-configured.
Not many manufacturers would think of using an old shipping container as their stand, but that is exactly what iGuzzini have done for the past few years. Inside, a control sequence demonstrates each of their product ranges in turn. Very impressive was the mini Laser Blade. Barely bigger than a chewing gum packet, this neatly engineered rectangular downlight can provide over 1000 lumens of light.
Lighting Industries Association (LIA). A big presence this year, with several new initiatives to support the industry and help clients when choosing lighting. Earlier this year they launched the LIA Verified scheme, providing a database of reputable lighting product that have been independently tested. A very welcome development in an industry with so many new start-up suppliers making some dubious claims.
Hacel had an interesting new range of suspended and very minimal fittings, with prototypes on display. The suspended hoops were particularly striking, and would make a good choice for entrance areas and mixed use spaces.
Led Linear, part of the Fagerhult Group, were one of several exhibitors showing off a great range of flexible LED tape. This has evolved from simple LED tape to an impressive range of form factors, colours and optics. Rubberised housing allows it be installed just about anywhere, with the right system.
Long established supplier of everyday lamps, Crompton, are soon to release a warm dim LED replacement lamp. The output becomes warmer as the light level drops. This mimics a traditional tungsten lamp, giving an intimate and relaxed ambience. Standard dimmed LEDs can just look dull by comparison. Not a new idea, but the launch by mainstream manufacturers such as Crompton means this technology is about to become commonplace.
And finally… for the most bizarre product in our opinion: If there was one technology who’s passing few would mourn, it must be the compact fluorescent “energy efficient” bulbs of the 1990s and 2000s era. Undeterred, retail orientated firm ExtraStar had a range of LED replica fluorescent lamps. Coming soon to a hipster café near you…
The two day show finished with the Lux Awards dinner, and a welcome glass of fizz. Next year will promise further innovations in controls and technology. Big developments in wireless technology such as Bluetooth Mesh will herald a new era of scalable and economic lighting controls, from simple houses to historic cathedrals. But we shouldn’t forget it is the light fittings themselves and their visual effect, which will be of prime interest to most clients and architects. From the selection above, and many others at the show, 2018 will be an exciting time in lighting design.