In a world increasingly focused on combatting climate change, government policies are evolving to align with ambitious carbon reduction goals set forth by regulations such as the Climate Change Act 2019. These policies are geared towards reducing carbon emissions and aiming for net-zero greenhouse gases by 2045 in Scotland. Each nation within the UK has set its own specific targets, making it essential to refer to region-specific regulations.
This article delves into the changes and their effects, providing a comprehensive overview of what you need to know.
WHAT ARE THE CHANGES?
The amended Technical Handbooks and Approved Documents now set higher standards under Section 6 (Scotland), Part L (England), and Part L (Wales). These standards have set new values for domestic and non-domestic buildings, which vary depending on the regulation your local authority is applicable to. Each standard has varying categories, which typically refer to various general subjects.
Each of these categories contains further detailed subcategories, which need to be fully explored with your architect and energy assessor.
- Energy Demand is the primary energy rate, calculated in kWhPE/m2 Per Year and determines how much energy will be required to heat your home, influenced by the fuel type and fabric.
- Carbon Emissions are calculated in kgCO2/m2 Per Year and determine how much carbon your new home can generate, also influenced by the fuel type and fabric.
- Building Envelope or Fabric is calculated in kWh/m2 and determines the heat loss through the fabric of the building (windows, doors, walls, roofs, floors, etc.) and is influenced by the fabric only.
- Fuel Type is how you plan to heat your home, either through Electricity (the preferred route, as it can derive from renewable sources), Gas, Biomass, etc. The type of fuel you choose influences all other factors.
- Air Tightness is determined by how permeable your fabric is. The more air that can escape through the fabric, the more heat will be lost. This is calculated in m3/(h.m2) at a specific pressure rating of 50 pascals.
- Ventilation is how you plan to ventilate your home to achieve a healthy environment. This can be done naturally, via mechanical extraction or a mixture of both.
For further reading on these topics, check out:
- What Is The Fabric First Approach?
- The Importance Of Airtightness In A Low Energy Home
- Exploring The Dynamics Of Natural And Mechanical Ventilation
Within each of these categories, a Target Rate is set by a Notional Dwelling. This Notional design depicts what the new standards would expect your home to be designed to and sets a Target figure your dwelling must meet or exceed in order to pass SAP. The more you exceed this rating, the better your SAP result will be and the more energy-efficient your home.
That being said, it’s not always as simple as it sounds, as so many contributing factors affect the final SAP rating, and small tweaks in the figures can impact the final rating more than others. Reviewing which of these most impacts your final result should be explored with your design team during the design process.
These Target figures have all been reduced in the new regulations and are now much harder to meet than in previous regulation versions. The target figures vary across the UK, so please ensure you are trying to meet the correct target for your project location.
HOW DO I KNOW WHAT TARGETS I NEED TO MEET?
These changes are reflected in SAP (Standard Assessment Procedure) to give you an overall rating on your new dwelling, finally providing an EPC Rating (A, B, C etc.) that determines your home is now habitable.
SAP is the design tool used to determine overall performance figures for your new dwelling. It takes into consideration all the areas listed above (and more) to determine if the specification for your new home will pass or fail.
SAP will set a Target Rate for each of the key areas listed above. This Target Rate is determined by a Notional Dwelling of your size that determines how your dwelling is expected to perform. This Target is then compared against your actual dwelling rate to determine if you meet or exceed the Target Rate. Meeting or Exceeding all of the Target Rates will result in a Pass. If you don’t meet all or even one specific value, your SAP will fail, and the dwelling will not be deemed as compliant.
A Designed SAP should be produced and issued to the local authority during the Design Stage. You will need to work with your Architect and Design Team to determine the best approach to achieve a compliant Designed SAP rating. The Designed SAP will determine how close you are to meeting or exceeding the Target Rate and will give a basis to then determine which areas need work to achieve a Pass.
We always advise to compare your Dwelling Rate against your Target Rate at design stage to ensure you aren’t just passing. If you just scrape through the SAP and slight alterations happen on site (material availability or poorer air tightness results) your final As Built SAP to produce your EPC could fail, causing remedial measures on site to achieve compliance.
Each of the Technical Handbook Sections and Approved Documents will set Targets you need to meet in order to be Compliant with Regulations. Each Section will give maximum allowable figures for each of the key topics listed, However, these figures aren’t always the Maximum value acceptable under the standards, so please be mindful of this when choosing products or elements of Fabric that state they achieve a compliant figure. The Compliant figure set for each of these areas is generally a poorer figure than what’s depicted in the notional dwelling specification, so picking all products that just meet minimum regulations will probably result in a SAP Rating that fails.
Work with your Architect to ensure the specification you are looking at will ultimately achieve compliance with not only the regulations for each element, but also the notional dwelling specification and other key factors like cold bridging. They can work with your supplier to determine details required to ensure you get the results you need.
HOW DO I ENSURE I MEET THESE TARGETS?
Speak to a trusted professional in the industry, who can guide you through all the variables, how these impact your overall rating, and whether you will meet or exceed compliance.
This can be done through your Architect and should involve your Energy Assessor, Heating Designer, Ventilation Specialist or even Kit Contractor, who can all work together to deliver the preferred values you need to maximise the energy performance of your new home.
At AC Architects we have been exceeding Targets set by the Building Regulations for well over a decade. Since 2008 we have always aimed to get the maximum fabric efficiency from each of our designs using the Fabric First Approach. This ensures you invest in the fabric of your home to achieve the most comfortable and efficient environment, maximising solar gain and reducing heat losses to create an efficient environment for years to come.
We all recognise the need to reduce our Carbon Footprint, and setting these targets for new dwellings will help us achieve what we need to as a nation, something we should all be mindful of when considering building our own homes.
Designing and building to even higher standards as set by the Government will help reduce your Carbon Footprint, giving you peace of mind that you have contributed positively toward addressing Climate Change, leaving a lasting impact on carbon footprint for years to come…it could also reduce your financial outgoings, too!
For more Self Build advice, take a look at the learning centre or follow the link below to arrange a free initial consultation with one of our team.