Building Performance Evaluation Programme: A selection of findings from domestic projects presentation on behalf of Innovate UK by Ian Mawditt

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1 Building Performance Evaluation Programme: A selection of findings from domestic projects presentation on behalf of Innovate UK by Ian Mawditt

2 Content Portfolio overview Building fabric performance: overview Building services: a sample of common findings MVHR meta-study (ongoing)

3 Building Performance Evaluation Programme 8m Innovate UK funding: four year programme running 2010 to 2014 Domestic new build and non-domestic new build or major refurbishment Projects are self-selected case study investigations of individual buildings or developments Generally, these are not main stream homes: they are designed to be high-performers

4 BPE programme profile: domestic projects

5 Locations 46 Project sites: The south of England and Scotland are well represented, and two projects in Wales Central regions of East Midlands and Yorkshire & Humberside also have a significant representation West Midlands and Shropshire and most of the North West are not well represented

6 20 Construction type (domestic) Timber Steel Concrete Masonry Masonary SIPs

7 18 Size of developments <5 5 to to to 100 >100

8 Number of dwellings The total number of dwellings in the programme is 366 (across 46 sites), representing developments with a total of 3,989 dwellings, Most development sizes one off through to volume build are represented in the portfolio

9 Three main approaches for dwellings to achieve low energy use Traditional housing design with a degree of renewable energy systems (including biomass heating, photovoltaics, solar water heating, air source heat pumps, etc.) Passive House / Passivhaus design MVHR with exceptionally good insulation and airtightness Passive solar large south-facing windows, and small north-facing windows, typically with natural ventilation and exceptional insulation

10 Building fabric performance: overview and examples of the results

11 Note on data used Values presented are taken from BPE programme field measurements and not test/commissioning results for the purpose of building completion or regulatory acceptance.

12 Building fabric performance Physical methods for measuring the building fabric performance included: Air permeability testing Coheating tests In-situ U-value measurements Thermography

13 n total = 54 dwellings Design Values: n>5.0 = 3 n 3 to 5 = 24 n 1 to 3 = 7 n<1.0 = 20 Tested air permeability results (m 3 /h)/m (design values in light blue) Measured Mean =

Coheating: whole house heat loss This is a measure of a building s total heat loss through its fabric and ventilation, using an independent and closely controlled heating system.

14 Coheating: whole house heat loss This is a measure of a building s total heat loss through its fabric and ventilation, using an independent and closely controlled heating system. Environmental conditions and energy use are recorded, allowing the heat loss coefficient (W/K) to be calculated (heat input vs. Δt). Image courtesy of CeBE, Leeds Metropolitan University

15 Heat Loss Coefficient (W/K) Sample from BPE coheating tests Predicted Measured Design HLCs range from 37 to 135 W/K, mean 87 W/K Measured HLCs range from 39 to 221 W/K 72% HLC measured > HLC design

16 Heat Loss Coefficient (W/K) Sample from BPE coheating tests Predicted Measured 6 PH dwellings quick analysis Design HLCs range from 37 to 64 Measured HLCs range from 39 to 62 Mean difference (design-measured) is 2.8 W/K s.d

17 Heat Loss Coefficient (W/K) Sample from BPE coheating tests Predicted Measured Non PH dwellings quick analysis Design HLCs range from 52 to 135 Measured HLCs range from 39 to 221 Mean difference (design-measured) is 25.6 W/K s.d

In-situ U-value measurements Flux sensors

18 In-situ U-value measurements Flux sensors provide a direct measure of heat transfer through an element. Often performed in tandem with coheating test U-Value can be calculated by using the resulting heat flow and local temperature data (Δt). Images by CeBE, Leeds Metropolitan University

19 In-situ U-values: ceilings Mean = 0.10 W/m 2.K Design U-value = 0.10 W/m 2.K

20 In-situ U-values: ceilings Mean = 0.17 W/m 2.K Mean = 0.10 W/m 2.K Design U-value = 0.10 W/m 2.K

21 In-situ U-values: ceilings Examples of insulation discontinuity at eaves and at gable in cold loft roofs

22 In-situ U-values: ceilings Mean = 0.17 W/m 2.K Overall Mean = 0.13 W/m 2.K Mean = 0.10 W/m 2.K Design U-value = 0.10 W/m 2.K

23 In-situ U-values: walls Design U-value = 0.13 W/m 2.K Upper Mean = 0.11 W/m 2.K Lower Mean = 0.10 W/m 2.K Overall Mean = 0.11 W/m 2.K

24 Building services: Examples of common findings

25 Ventilation systems Mixture of systems in portfolio including: MVHR (240 dwellings) MEV (qty tbc) EAHP (<10 dwellings tbc)

26 A number of high quality installations

27 A number of compromised installations

28 Quality installations are not always flawless Incomplete insulation can be the cause of significant condensation

29 Heating and hot water systems Mixture of systems in portfolio, including: Gas condensing boilers and unvented cylinders Biomass central heating Heat pumps: air source and exhaust air Warm air coils District heating systems

30 System Complexity Has been found to cause problems: 11 1 site wiring a lot of connections 2 commissioning potential conflict usability

31 Building Services Energy systems, particularly ventilation and heat pump installations, are not always well integrated into the design from an early stage The impact of changes to construction details (often at site level) are not always assessed Access for maintenance and cleaning can be over-looked Contractors not experienced with some of the newer technologies and controls lack a mentor to advise and check work

32 Building Controls Ensuring that low carbon energy systems perform as well as possible relies on residents having a good understanding of why and how they work Several common issues have been found: the systems and how to effectively control them had not been explained well enough during the hand-over process the controls were too complex automatic controls often overridden instructions were not in English

33 Summary of findings-to-date MVHR meta-study (ongoing)

34 Overview A meta-study of domestic projects that have MVHR systems Why? Increased take-up of MVHR systems in many new homes Insufficient data available about MVHR performance Aware of emerging concerns from end-user groups, which has resulted in negative press An opportunity presented whilst the BPE programme is live access to projects and teams

35 Number of Dwellings Air Permeability Range n = 54 n<1 = 16 n<3 = 29 n<5 = 41 min = 0.26 max = Passivhaus Non-Passivhaus Air Permeability (m 3 /h)/m 2

36 Design Review MVHR meta-study (ongoing)

37 Number of Dwellings 40 Design Flow Rates Meet Part F? Passivhaus Non-Passivhaus Yes No Unknown

38 Summary design assessment Design data supplied for 80% of dwellings Design data (where supplied) for all 2006 dwellings meet the air flow design guidance published in AD F % of the designs for 2010 dwellings (where supplied) meet the air flow design guidance published in AD F 2010 Design air flow rates between supply and extract show an imbalance in 36% of all designs submitted (not a requirement of Part F) 11% of all systems reviewed had no access to design data at time of commissioning

39 Measured Characteristics MVHR meta-study (ongoing)

40 Number of Dwellings 25 Measured Flow Rates Design Flow Rates PH Non PH Yes Borderline No

41 Chart 5: Mean Percentage Deviation (Balance Between Supply/Extract) Normal Dev <15% = 25 Normal Dev >15% 27 n= 52 Boost Dev <15% 22 Boost Dev >15% 26 n= Measured Deviation Normal %

42 Summary measurements 46% of all systems measured do not meet the minimum flow rates published in AD F tables 1.1a/b (2006) and 5.1a/b (2010) 56% of all systems measured do not meet their own specific design air flow (low) rates 45% of all systems measured in boost do not meet their own specific design air flow (high) rates Compliance with Part F 2010 is presenting the greatest challenge: BPE programme does span a transitional period 67% non-compliance with 2010 ADF opposed to 35% noncompliance with 2006 ADF

43 Summary measurements (cont d) 52% of all systems have an imbalance (>15%) between supply and extract in normal speed. Imbalance is similar for boost speed 54% There is a tendency for metal rigid ductwork to deliver the most successful installations Note: many rigid plastic installations reviewed switch to flexible at unit and/or room terminals; metal tends to be 100% rigid Passivhaus installations are most likely to meet design criteria

44 Summary

45 Summary This is a selection of findings, many outputs have not been postprocessed and analysed at this point. 54 air permeability test results collated so far with a mean of 3.2 m 3.h -1.m (national mean for post-2006 dwellings is 6) 21 coheating HLC test results ranging from 39 to 221 W/K, with the highest Passivhaus measuring 62 W/K System complexity often leads to problems with space requirements, inexperienced installers and commissioners, and poor understanding by occupants. Keep it simple wherever possible MVHR installations have been successful in many projects, particularly Passivhaus. Problem systems mostly occur when systems are crammed into inappropriate spaces, and/or where there has been inadequate commissioning and user guidance.

46 Thank you for listening

Characteristics and performance of MVHR systems A meta study of heat recovery ventilation systems in new dwellings

Characteristics and performance of MVHR systems A meta study of heat recovery ventilation systems in new dwellings FM Nectar Presented by: Ian Mawditt, fourwalls Consultants Professor Rajat Gupta, Oxford