Breathing and Airtight? Is this possible. AECB 2006 Peter Warm Buildings Energy Consultant

Transcription

1 Breathing and Airtight? Is this possible AECB 2006 Peter Warm Buildings Energy Consultant

2 Definitions Infiltration Ventilation

3 Definitions -50 Pa Air Leakage Test Infiltration Ventilation

4 How does infiltration occur? Wind effect

5 How does infiltration occur? Stack effect

6 Air Leakage test

7 Air Leakage vs. Infiltration Air changes at 50 Pa Approximate normal air changes Typical UK house Good UK practice Scandinavian & Canadian practice < 1 < 0.1

8 Infiltration routes

9 Joist Hangers

10

11 Why is airtightness desirable? Reduction in heating energy Reduction in fossil fuel pollution

12 Fabric and Infiltration Heat Losses Infiltration Fabric B Regs High Insulation

13 Why is airtightness desirable? Reduction in heating energy Reduction in fossil fuel pollution Buildings more comfortable Reduction in draughts

14 calm windy OK OK Airtight Airtight OK? calm Huge heat loss Very uncomfortable windy Leaky Leaky

15 Why is airtightness desirable? Reduction in heating energy Reduction in fossil fuel pollution Buildings more comfortable Reduction in draughts But ventilation still required for good air quality Some systems not worth installing in leaky houses

16 Ventilation systems Natural ventilation Trickle vents Opening windows Passive stack ventilation Mechanical Extract fans Whole house extract Room ventilator with heat recovery Whole house mechanical ventilation with heat recovery

17 Windows Poor control cannot be left open Can be left open but often cannot be reached Ventilator gives better control

18 Passive Stack Ventilation

19 Mechanical Ventilation

20

21 Whole house extract systems

22 Room ventilator with heat recovery

23 Room ventilator with heat recovery

24 Whole house heat recovery ventilation

25 Conclusion: Airtightness Essential for energy saving, global warming Essential for comfort Needs a ventilation system to be designed

26 Why is Breathability desirable? No absolute moisture barriers No trapped moisture Provides evidence of building failure Self healing from building defects

27

28 Vapour movement through wall practically zero vapour pressure kpa SVP VP SVP VP OUTSIDE thickness from outside m m INSIDE

29 Fully Filled Cavity

30 Vapour movement through wall Interstitial Condensation occurs vapour pressure kpa SVP VP OUTSIDE thickness from outside m m INSIDE

31

32 Vapour movement through wall No Condensation vapour pressure kpa SVP VP OUTSIDE thickness from outside m m INSIDE

33 Breathing and airtightness possible? 10 Mass flow through fabric g/h per m Infil-Bregs Infil-Gold Vapour- LVR A breathing structure can still be extremely airtight Vapour- HVR

34 Healthy buildings Avoid formaldehyde-emitting emitting materials Solvent based adhesives & paints Man made carpet fibres Chipboard, plywood,osb Use natural, non-toxic paints Treat timber only off site and where absolutely necessary Avoid upvc if possible

35 Practically every decision affects energy consumption Power to Low Airtightness High levels energy the shower lights strategy of insulation Airtightness details Heating strategy Services penetrations Hot water supply Thermal bridges Passive Warm roof, solar cold roof? Controls Solar water heating Ventilation Glazing Central performance heating? Appliances MVHR PSV Indoor air quality Water Daylighting Pressure test

36 Practically every decision affects energy consumption Power to Low Airtightness High levels energy the shower lights strategy of insulation Airtightness details Heating strategy Services penetrations Hot water supply Thermal bridges Passive Warm roof, solar cold roof? Controls Solar water heating Ventilation Glazing Central performance heating? Appliances MVHR PSV Indoor air quality Water Daylighting Pressure test

37 The End