Thermal Performance: Part L1A - Masonryfirst.com

Thermal Performance: Part L1AGeneral conclusionsAs apparent in Figure 3,the effect of changing the fabricand/or services specification is dependant on dwellingtype, with improvements to the fabric of greatest benefitto dwellings with a large exposed area, particularlydetached houses. Dwellings with a relatively small exposedarea benefit more from the use of low and zero carbontechnologies.Further outcomes from the study are provided below:Compliance with Part L: 2010• Compliance can be achieved without the use ofrenewables, but enhancements to the services may benecessary if fabric specifications 1 or 2 are used. This doesnot have to include MVHR.• Use of fabric specification 3 will, for most dwellingtypes, be adequate to achieve 2010 compliance withoutenhancements to the services.Compliance with Part L: 2013• Compliance can be achieved without renewables,providing there is a high standard of fabric performancei.e. somewhere between fabric specification 3 and 4. Inaddition, the services may need upgrading with one ormore of the options featured in the study.• Alternatively, a more relaxed fabric specification can beused in conjunction with a renewable technology suchas PV; although this may be a more expensive route tocompliance.Compliance with Part L: 2016Performance requirements for 2016 are currently underreview and may not be finalised until the end of 2011or early 2012. However, recommendations have beenpresented to the government and will be subject to publicconsultation during 2011. Performance will no longer bemeasured in terms of a percentage improvement overPart L 2006, instead specific CO 2 targets will be set. Therecommendations [9] are that the ‘built performance’emissions from new homes should not exceed:• 10 kg CO 2 /m 2 /year for detached houses• 11 kg CO 2 /m 2 /year for other houses• 14 kg CO 2 /m 2 /year for low rise apartment blocks.The Carbon Compliance Standard applies to builtperformance, whereas the 2006 Regulations relateto designed performance. For this reason therecommendations cannot be directly compared with the2010/13 performance requirements. However, in additionto any improvement achieved by moving from designedto built performance, the % improvements [9] on the 2006standard would be:• 60% for detached houses• 56% for other houses• 44% for low rise apartment blocks.(This range is represented by the greyed out area on Figure 3).Figure 3 shows that 2016 compliance can be achievedin a variety of ways using fabric specification 3 or fabricspecification 4, in combination with one or more heatrecovery systems and/or PV. The extent to which thesetechnologies are needed depends very much on dwellingtype and level of fabric performance.In some cases, it may just be possible to achieve compliancewithout the use of renewables if a very high standard offabric performance is applied (fabric specification 4 orPassivhaus equivalent) and heat recovery systems are used.However, this is based on the current SAP methodology andassociated assumptions, which may be revised in the run upto 2016.It is likely that for 2016 compliance, the optimal U-valuefor external walls may stop at around 0.15 - 0.18 W/m 2 K,reflecting the cost-benefit limit of insulation as comparedto other options for reducing CO 2 emissions. However,whatever the eventual outcome is, there is a wide range ofconcrete and masonry options that can meet the highestlevels of fabric performance, and easily exceed the FEESrecommendations where required.In addition to meeting the CO 2 targets detailed above,2016 compliance will also require that the minimum fabricperformance requirements specified in the FEES are alsosatisfied. These are currently set at:• 39 kWh/m 2 /year for apartment blocks and mid terracehouses• 46 kWh/m 2 /year for semi detached, end of terrace anddetached houses.All of the dwellings in Figure 3 built to fabric specifications3 and 4 complied with the FEES targets.8