Building Regulations Part L & Energy Labelling

Transcription

1 More than insulation. PART L GUIDE IRELAND JULY 2006 Energy efficiency in new housing Building Regulations Part L & Energy Labelling COST EFFECTIVE THERMAL SOLUTIONS Efficient fabric insulation - Lower energy demand

2 Part L Building Regulations Reduce the energy dema effective energy efficient Thin-R Choosing the right insulation for your project is vital when building dwellings to the new Part L regulations which will result in energy efficient, comfortable dwellings. The revised Part L of the Building Regulations came into force on the 1st July 2006, and has heralded significant changes in the way in which buildings in Ireland are measured in terms of energy performance. Rigid Thermal Insulation This guide aims to explain those changes and simplify specification of all inputs into the design to assist in improving energy efficiency, cut CO2 emissions and result in a better Building Energy Label. Further comprehensive information on regulation changes is available in a series of technical briefing notes available from Xtratherm, contact Technical Support for copies. 02

3 Save Energy Save Money Save Space Thin-R nd by providing cost fabric insulation EPBD and Whole House Performance The adoption of the Whole House approach to performance has been lead by the integration of the Energy Performance of Buildings Directive (EPBD) into the regulations. The directive contains a range of provisions aimed at improving energy performance in residential and non-residential buildings, and asks that Energy Labels be provided for all buildings by New dwellings will have to be provided with energy labels from 1st Jan (An exemption will apply to a new dwelling for which planning permission is applied for on or before 31 December 2006 provided the new dwelling involved is substantially completed by 30 June 2008.) The directive aims to reduce energy use in all our buildings and recognises that it is through energy improvement of the existing building stock that the greatest environmental impact will be achieved. New houses built in accordance with Part L buildings regulations will perform well and will typically achieve a C Energy Rating when built to the notional Elemental values given in the Part L Document. By Including reasonable, cost effective, measures at the design stage and some improvements in detailing during the construction, a new build dwelling can achieve a B rating. DEMONSTRATING COMPLIANCE Compliance under the building regulations is based on restricting the amount of CO2 created by a building by demonstrating that the design Carbon Dioxide Emission Rate (CDER) is within a specified target - the Maximum Permitted Emissions Rate (MPCDER). The MPCDER is derived from a NOTIONAL building of the same size and shape as the actual dwelling - but with specific characteristics taken from Appendix C in Part L, that standard specification includes; FABRIC U-VALUES ELEMENT U-VALUE W/m 2 K Floors 0.25 Walls 0.27 Roofs 0.16 Glazing* 2.2 *At 25% ops to floor area. Allowance for Thermal Bridging x total exposed surface area. Plus The notional building is also deemed to have 1 chimney, 3 extract fans, have 2 sheltered sides, have 0.5 air changes per hour among other specifications. It would be reasonable to assume then that where the design specification matches these notional building defaults, that the constructed dwelling will comply with Part L without the need for early calculation, however, compliance must be verified by calculating both the CDER and MPCDER using the DEAP calculation procedure when all relevant details of the final construction are known. GLOSSARY BER CDER DEAP EPBD HER LZCs SEI MPCDER Building Energy Rating Carbon Dioxide (CO2) Emission Rate Domestic Energy Assessment Procedure Energy Performance of Buildings Directive Heat Energy Rating Low and Zero Carbon Technologies Sustainable Energy Ireland Maximum Permitted (CO2) Emission Rate 03

4 Energy Assessment and Labelling DOMESTIC ENERGY ASSESSMENT PROCEDURE (DEAP) The CDER & MPCDER are determined by completing a DEAP calculation (Domestic Energy Assessment Procedure) which is now mandatory for ALL new dwellings and should be completed at design stage, to prove compliance with Part L. A Final DEAP calculation should be completed once the specification of the final construction is known - this final version will be used to determine the BER. (the DEAP procedure replaces the HER method included under the previous regulations.) The DEAP Excel Spreadsheet software can be downloaded from the SEI website; and the full version of the software is available from early In addition to restricting CO2, you must also ensure that minimum standards are achieved in certain areas of the construction. There is an acceptable level of heatloss through the building fabric. Ensure acceptable fabric insulation, walls, floor, roof & glazing. Ensure acceptable thermal bridge heatloss. Ensure acceptable air infiltration heatloss. Ensure acceptable controls for space heating and hot water supply. Ensure acceptable insulation of hot water storage vessels, pipes and ducts You may still be able to design a dwelling that has acceptable CO2 emissions but will fail because these minimum levels have been exceeded. (Particular attention should be paid to the areas and performance of glazing and doors in a design.)

5 Thin-R ENERGY LABELLING The DEAP calculation is also used to determine the total energy required to; B1 Heat the space Heat the water To ventilate To light the property The energy used is measured in kwhr/m 2 /yr and is determined by the DEAP calculation; it is upon this figure that the Energy Label (A to G) will be based. Although not required under Part L, the Building Energy Rating (BER) will prove a significant component in how new houses are marketed. 90KWhr/m 2 /yr It has been estimated that new houses built to the Notional Figures quoted in Part L will achieve a B or C label. Who can provide these calculations? Any competent person will be able to complete a DEAP calculation using the SEI spread sheet to calculate the CO2 emissions for a design that will satisfy building control; however only Independent accredited assessors that have passed an exam of competency and are continually monitored under an accreditation scheme can produce a BER Energy Rating for a building. These assessors are listed on the SEI website. ROBUST DETAILING AND AIR PERMEABILITY As well as achieving Target U-values, the revision has placed great emphasis on the Continuity of Insulation in the form of Robust Detailing. The building fabric should be constructed so that there are no reasonably avoidable thermal bridges in the insulation layers, caused by gaps within the various elements, at joints between elements and at the edges of elements such as window and doors surrounds. The goal is to improve the air permeability or the uncontrolled movement of air, both into and out of the dwelling, through cracks and gaps in the building envelope. Most air leakage in a typical dwelling follows routes such where service penetrations or junctions between building elements that remain unsealed. Careful detailing on site will drastically improve the CDER at minimal cost. In calculating the CDER, a default penalty of 0.11 is added to the average U-value of the building fabric to take account of these nonrepeating thermal bridges making compliance more difficult to achieve. Following the details set out in the publication Right on the Site, Issue No. 28, is set as a minimum standard for addressing the thermal bridging. The more detailed document Limiting thermal bridging and air leakage: robust construction details for dwellings and similar buildings is suggested for further improvement, but is based on UK detailing Xtratherm has produced bridging details SPECIFIC to Irish construction practices that perform substantially better than the standard details that have been measured in accordance with BRE IP1/06 and perform substantially better than those used in the notional DEAP figures, using these advanced details will contribute to achieving a better rating, contact Xtratherm Technical Support for information.

6 Typical Example (Semi-Detached) The example Semi-Detached dwelling (below) is calculated using the default figures for the notional building; the resultant CDER for the actual building closely matches the MPCDER demonstrating that the building complies with the requirements under Part L, but with no margin of error should performance of air permeability or thermal bridging be less robust than calculated for at design stage. It also means that any small trade off in thermal performance in wall, floor, roof or glazing performance will automatic lead to a failure. Reducing performance in any one component of the Energy Efficiency systems will reduce the resultant energy label. MPCDER 31.27kg/m 2 y STANDARD SPECIFICATION as notional values above C2 Label Wall U-value 0.27 W/m 2 K Floor U-value 0.25 W/m 2 K Roof U-value 0.16 W/m 2 K Glazing 2.2 W/m 2 K Thermal Bridging 0.11 Air changes 0.5 Heating Controls Standard Boiler Efficiency 78% EE Lighting 30% Front Elevation CDER KWhr/m 2 /Yr 152 Rating C2 IMPROVED SPECIFICATION improvement to achieve B1 Label Rear Elevation Wall U-value 0.27 W/m 2 K Floor U-value 0.20 W/m 2 K Roof U-value 0.14 W/m 2 K Glazing 1.5 W/m 2 K Thermal Bridging 0.08 Air changes 0.2 Heating Controls Full Zoning Boiler Efficiency 97% EE Lighting 100% Heat recovery & vent. Inc. CDER KWhr/m 2 /Yr 90 Rating B1

7 Thin-R Warm-R Homes Type D2 STEPS TO ACHIEVING AN ENERGY EFFICIENT HOME Well insulated Building Fabric Providing effective insulation to the building fabric cuts the energy demand for space heating requirements the largest proportion of our energy demand. The most energy efficient houses built are Passive, ie. houses so well insulated and sealed that they require no conventional heating systems, using heat gain from the sun and internal gains such as cooking and lighting to heat the dwelling. Improved Robust Detailing As well as achieving effective U-values, emphasis must be placed on Robust Detailing - or the Continuity of the Insulation layer avoiding any thermal bridges. Bad detailing can account for up to 40% of heatloss through the building fabric in a presumed well insulated dwelling. Xtratherm systems that include corner & reveal boards for walls and perimeter detailing for floors have been approved and exceed the new Building Regulations. Air Tight Build Air leakage from buildings, the uncontrolled flow of air through gaps and cracks in the fabric of dwellings (Draughts) is a major cause of energy loss and increased CO2 emissions. Designing effective air barriers and sealing any gaps in the build will save energy, Air Pressure testing of properties can be used to measure air permeability. Effective Boilers Boilers will convert fuel to energy with varying efficiency. Condensing boilers have a minimum efficiency of 86% but can be as efficient as 97%, a vast improvement on earlier technologies. Effective Heating Controls Effective control of space & water heating facilities in a property is essential to assist in energy efficiency. Full time & temperature zoning is a requirement in properties over a certain size under the building regulations but is recommended for all properties as Best Practice Efficient Secondary Heating An assumption is made under the new building regulations that a certain amount of energy is used on secondary heating. Using a more efficient appliance such as a condensing gas fire rather than the default electric will improve efficiency, and burning renewables such as wood will also reduce CO2 emissions. Controlled Ventilation This is not to be confused with air-permeability, the controlled flow of air into and out of the dwelling through purpose-built ventilators is required for the comfort and safety of the occupants. Providing ventilation in the correct manner will help maintain efficiency, or once a well insulated airtight build is achieved (Permeability less than 4m 3 /h/m 2 ) mechanical ventilation with heat recovery become very effective. Energy Efficient Lighting As we achieve better control of space heating requirement through effective insulation of the building fabric and good control of our hot water needs the energy demand for lighting becomes a bigger proportion of the energy demand and a major contributor to CO2 production, not least because the energy is electric based which is a costly fuel and dirtier than all other fuels. Using energy efficient light FITTINGS will reduce CO2. Low & Zero Carbon Technologies (LZCs) As previously mentioned, the first step in energy efficiency in new build is to provide a robust, energy efficient building fabric before incorporating any Low or Zero Carbon Technologies (LZCs). It do not make sense to install renewable generation into a design if much of the output is to be wasted through inefficient usage. By providing a well insulated building fabric, the energy demand will be lower, and therefore the costs less to run. The building fabric will last a lot longer than the services that are put into it. Most technologies such as boilers, glazing, and renewables will be replaced within one or two decades. It is therefore vital to get the fabric right at time of construction. It is always more costly to insulate properly at a later stage. Clearly renewable measures are important; they simply should not be regarded as a substitute for reductions in heat loss in new homes, and they will be required as we move towards net zero-carbon heating and beyond, but carbon reductions/energy savings of 25% or better than the regulations can be achieved, and subsequent genuine cost savings made, without a huge investment. SOLAR GAIN The Free energy good design takes advantage of solar gain. Solar Water Heaters Can provide up to 50% of hot water requirements on a SE-SW roof at 60º Photovoltaics Uses energy from the sun to create electricity to run appliances and lighting. PV requires only daylight - not direct sunlight - to generate electricity. A typical array would cover 10-15m 2 of roof area, to provide 50% of electricity. Pellet Stoves Energy from biomass is produced from organic matter of recent origin - not fossil fuels, the CO2 released during burning is balanced by the CO2 absorbed during the fuel's production - this is Carbon Neutral. Storage of pellets is a major consideration. Ground Source Heat Pump The ground keeps a constant temperature of about 11-12ºC Ground source heat pumps (GSHP) can transfer this heat into a building to provide space heating. For every unit of electricity used to pump the heat, 3-4 units of heat are produced. Particularly suitable for under floor heating because of lower operating temperatures.

8 The Xtratherm range of high performance insulation boards provides the complete solution for newbuild and refurbishment. Thin-R/PR Pitched Roof Effective insulation of roof area Reduced insulation thickness Reduces thermal bridging Minimises intrusion into living area Ventilated Pitched Roof Warm Pitched Roof Hybrid Pitched Roof Thin-R/TP Flat Roof Insulation & decking in one fix For new & refurbishment roofs Easy to handle & install Rapid weather proofing New Flat Roof Refurbished Flat Roof Thermal Decking Thin-R/CW Cavity Wall Robust tongue & groove jointing Clear cavity maintained No exposure restrictions Low emissivity foil facings Extra thermal performance Partial Fill Cavity Walls Thin-R/TL Thermal Lining High thermal performance Drylining & insulation in one fix Shorter drying time Responsive insulation system Thin-R/UF Under Floor Extra thermal performance Suitable for under floor heating Reduced insulation thickness High compressive strength Masonry Walls Sloped Rafters Ceilings Solid Block Floor Under Screed Floor Suspended Timber Floor Zero O D P Zero Ozone Depletion Potential Technical Support The Xtratherm Technical Support team provide a single point of contact to offer assistance on a wide range of issues for both the Designer and Builder and can be contacted by phone, fax or . Full details of all Xtratherm products, along with full technical literature can be downloaded from the web site at: Good workmanship and appropriate site procedures are necessary to achieve expected thermal and airtightness performance. The example calculations are indicative only. Default values for components and cavities have been used, for specific U-value calculations contact Xtratherm Technical Support. Comprehensive guidance on installation should be consulted. Xtratherm technical literature and Agrèment certification is available for download on the Xtratherm website. The information contained in this publication is, to the best of our knowledge, true and accurate but any recommendations or suggestions which may be made are without guarantee since the conditions of use are beyond our control. Xtratherm Limited Kells Road Navan Co Meath Ireland Tel: (0) Fax: (0) info@xtratherm.com XT/ PartLNew(RoI)/ 8P/ 0407