1. My Energy Efficient Home

2. Agenda Planning and design – Site, climate, form and layout Building envelope and element performance – Thermal resistance – Condensation – Thermal mass – Air-tightness – Ventilation Codes and Regulations – Building Regulation Part L – SAP – Standard Assessment Procedure – Passivhaus

3. Energy Efficiency What is it? Why bother? – Running out of easily exploitable fossil fuel resources – Reducing overall environmental impact of construction – Reducing total demand for electricity however it is generated,; nuclear, biomass, wind – Saving consumers money Understanding the performance of the built environment is massively complicated. Even our most sophisticaed models and tests are simplifications of reality.

4. Planning and Design

5. External climate UK climate is cool temperate – Winter heat loss is the major energy efficiency design criterion. – We have cool wet winters and moderate, relatively humid summers – The future…

6. Internal climate Maintaining internal comfort is the key criteria – Temperature 15 o C – 30 o C / 18 o C – 22 o C during heating season – Humidity 40% - 70% Relative Humidity at 18 o C - 22 o C – Air movement Controlled ventilation 0.5ach Uncontrolled draughts 0.1m/s

7. Site Planning Can be really difficult to influence for some self builders – Most major house builders ignore it! But you should try and consider… Orientation Over-shading Shelter View and privacy Service runs – Remember that most situations can be managed even if the perfect solution is not achievable

8. Site Planning Orientation – Impacts on heat loss – Think about roof orientation for solar collectors – Overshading – Wind protection – Summer shading Achieving optimum orientation is frequently not possible

9. Site Planning Building form can have a significant impact on energy efficiency – Plan area – Configuration – Average height – Volume Form is influenced by planning, brief and site constraints. The major energy considerations are; – Overall surface area (which affects fabric heat loss) – Volume (which affects ventilation heat loss) and – Configuration as it relates to the south facade for potential solar gain.

10. Internal Planning The general aims for internal planning for energy efficiency are to: – zone internal spaces to maximise useful solar heat gain, minimise heat loss and achieve efficient distribution of heat – encourage the efficient circulation of ventilation air – minimise service runs to reduce standing heat losses from pipes and ducts

11. Building Envelope and Element Performance

12. Envelope Performance – The Basics

13. Thermal Resistance The thermal resistance of individual building elements is normally indicated by a U- value calculation At its simplest a U-value is the reciprocal of the sum of the thermal resistances of the layers in the construction

14. Thermal Bridging Adopt details recognised by Department of Communities and Local Government Use properly calculated values – This is what we do Adopt ‘punitive’ default values Use a conservative y-value Using poor thermal bridging (psi-values) will have a significant impact on building performance

15. Thermal Mass A measure of ability to absorb and store heat – Controlled by specific heat capacity of materials and their location relative to insulation and air-spaces High thermal mass homes are slow to respond to heat Low thermal mass homes respond more quickly A complex and much debated subject

16. Air-tightness and Ventilation Controlled ventilation Uncontrolled infiltration “Build tight – Ventilate right” Target ventilation 0.5 – 1.0ach Easy to precisely define an air permeability target – very difficult to hit it accurately – Natural – Combined natural and mechanical – Mechanical

17. Air tightness and Ventilation

18. Our Building Systems

19. – Low embodied carbon – Excellent thermal performance; High performance Kingspan insulation – Air-tight construction; proven products and details – Minimal thermal bridging; psi- values calculated – Manufactured off-site in a quality controlled environment, quick to construct on-site with minimal waste. Our Building Systems

20. Kingspan Logic – Pre-insulated timber frame system – Established timber frame system with variable performance characteristics – A leading Modern Method of Construction Kingspan Ultima – Premium performance pre-insulated timber frame system – Enhanced thermal performance properties Kingspan TEK – Structural insulated panel system – Next generation, high performance, engineered timber envelope solution – Whole building system

21. Our Building Systems

22. Performance Levels in Practice Part L 2013CSH 4+Lower EnergyPassivhaus Ground floor0.20 – 0.160.18 – 0.100.11/0.12~0.1 Ext wall0.19 – 0.150.19 – 0.100.15~0.1 Roof0.15 – 0.10 0.09~0.1 Sloping roof0.20 – 0.150.15 – 0.100.09~0.1 Windows1.8 – 1.41.4 – 1.10.83~0.1 Doors~2.0~1.81.30<0.8 Air-tightness7 - 3<31.5<1.0ach Thermal bridging0.08 – 0.050.05 - <0.03<0.040.00 Energy solution is very project specific and it’s difficult to generalise but this is what we experience

23. Building Regulations & SAP

24. Part L1A – Conservation of Fuel & Power 5 Compliance Criteria – Achieve Target Emission Rate (TER) and Target Fabric Energy Efficiency (TFEE) – Acceptable Dwelling Emission Rate (DER) and Dwelling Fabric Energy Efficiency (DFEE) – Stay within limits on design performance flexibility – Check for overheating – Make sure the dwelling can be operated efficiently

25. Part L1A – Conservation of Fuel & Power Achieving TER and TFEE Notional Dwelling Specification Roofs0.13 W/m2K Walls0.18 W/m2K Floors0.13 W/m2K Party Wall0.00 W/m2K Windows, roof windows, rooflights & doors1.4 W/m2K / g-value 0.63 Opaque doors1.00 W/m2K Semi glazed doors1.20 W/m2K Air Tightness5.00 m3/hr/m2 at 50 Pa Linear thermal transmittanceStandardised psi values (See SAP 2012 appendix R)

26. Part L1A – Conservation of Fuel & Power Design flexibility limits Limiting U-valuesW/m 2 K Roofs0.20 Walls0.30 Floors0.25 Party Wall0.20 Swimming pool basin0.25 Windows, roof windows, rooflights & doors2.00 Air permeability10.0m 3 /m 2 /hr@50Pa In practice, the building specification needs to be considerably better than the stated limiting values in many aspects of the design U-values are calculated using the methods and conventions set out in BR443 Conventions for U value calculations

27. Part L1A – Conservation of Fuel & Power Limiting the effects of heat gains in summer – SAP automatically runs a check to consider whether heat gains are excessive It’s not the most sophisticated – If the glazed area is <20% then low levels of daylight may increase the use of electric lighting – Consider shading in low energy buildings – Reduce internal heat gains from pipes by insulating them Effect can be significant

28. Part L1A – Conservation of Fuel & Power Ensure building Performance is consistent with DER and DFEE – Calculate thermal bridging – Consider party wall thermal by pass (semis, terraces and flats) – Measure air permeability

29. Part L1A – Conservation of Fuel & Power Air permeability – An achievable value is set at design stage – This must be measured at completion Earlier measurement is strongly advised if target is <3

30. Passivhaus

31. Contents What is Passivhaus? Why build Passivhaus? Passivhaus -v- the CSH? Is it difficult? How do you prove it? How much does it cost?

32. What is Passivhaus? Passivhaus dwellings typically include: – excellent insulation with minimal thermal bridges – triple glazing with solar shading – excellent levels of air-tightness – good indoor air quality, provided by a whole house MVHR system – well thought out utilisation of solar and internal gains

33. What is Passivhaus? Passivhaus dwellings typically include: – excellent insulation with minimal thermal bridges – triple glazing with solar shading – excellent levels of air-tightness – good indoor air quality, provided by a whole house MVHR system – well thought out utilisation of solar and internal gains

34. What is Passivhaus? In many cases, the small heating demand can be met using a compact services unit which integrates heating, hot water and ventilation in one unit. But a conventional boiler and small radiators will also work well.

35. What is Passivhaus? A dwelling is deemed to satisfy the Passivhaus criteria if: – the total energy demand for space heating and cooling is less than 15 kWh/m 2 /yr and – the total primary energy use for all fixed appliances, hot water and space heating and cooling is less than 120 kWh/m 2 /yr These figures are verified at the design stage using the Passivhaus Planning Package High levels of on-site quality control are essential to achieve the performance required

36. What is Passivhaus? For our house, currently: – the total energy demand for space heating and cooling is less than 12.6 kWh/m 2 /yr and – the total primary energy use for all fixed appliances, hot water and space heating and cooling is less than 97 kWh/m 2 /yr These figures will change as we continue to refine / develop the build

37. What is Passivhaus? How does our Passivhaus perform

38. What is Passivhaus? Ultimately it is the occupier who determines how energy efficient a home will be in use

39. What is Passivhaus? PassivhausCommon UK practice Compact and highly insulated No U-Values exceed 0.15 W/m 2 K. Almost always somewhat less U-values of approx 0.23-0.18 W/m 2 K but getting lower due to Part L improvements Thermal bridgingThermal bridges almost eliminated y = 0.01 Typically y = 0.08 OrientationPassive use of solar energy is a critical feature of Passivhaus design Some consideration of orientation in design and SAP, but energy savings from passive design are not normally considered. Windows and doorsGlazing and frames, have combined U-Values not exceeding 0.80 W/m²K Typically, 1.4-1.2 W/m 2 K but getting lower due to Part L improvements

40. What is Passivhaus? PassivhausCommon UK practice Envelope air-tightnessAir leakage is less than 0.6 times the house volume per hour. This is roughly equivalent to an air permeability value of between than 0.5 – 1.0 m 3 /hr/m 2 @ 50 Pa Design air permeability of 5 to 8 m 3 /hr/m 2 @ 50 Pa. VentilationMVHR. Fresh air can be passively warmed or cooled by @ 8 o C in ground ducts prior to passing through the MVHR Trickle vents, extract fans, or passive stack ventilation is commonly used. MVHR increasing due to Part L improvements AppliancesEverything is low energyIncreasing use of efficient lights and appliances Energy demand Less than 15 kWh/m 2 /yrTypically ~55 kWh/m 2 /yr

41. What is Passivhaus – Performance Summary Part L 2013Low EnergyPassivhaus Ground floor0.20 – 0.160.18 – 0.100.15 – 0.09 Ext wall0.21 – 0.150.19 – 0.100.15 – 0.09 Roof0.15 – 0.10 0.15 – 0.09 Sloping roof0.20 – 0.150.15 – 0.100.15 – 0.09 Windows1.8 – 1.41.4 – 1.10.8 Doors~2.0~1.80.8 Air-tightness7 - 3<30.5-1.0 Thermal bridging 0.08 – 0.050.05 - <0.03<0.01 Energy solution is very project specific and it’s difficult to generalise but…

42. Why build Passivhaus? Low running costs Prevent future fuel poverty Easy to live in Thermally comfortable – No draughts – Even temperature distribution Good indoor air quality Excellent acoustic performance

43. My Energy Efficient Home