Building Sustainability Why Passive House? Paul McAlister RIBA Northern Ireland s First Certified Passive House Designer
Agenda Timeline to Carbon Zero Features of a Passive House How it works Benefits of a Passive House
Timeline to Carbon Zero The Government has indicated its intention to use the Code for Sustainable Homes as the basis of future Building Regulations Part L changes, proposing it as a route map for new homes to become net-zero Carbon by 2016.
What are the key features of a Passive House? High levels of insulation Triple glazed windows, south oriented desirable Draft-proof building envelope Mechanical ventilation with heat recovery Minimized thermal bridging
How to achieve Passivhaus? Energy limit Useful energy for space heating 15 kwh/m 2.year ( load typical 3Kw ( Typical 300-250 kwh/m 2.year, load 18-25kw ) Primary Energy demand for all energy services (including domestic electricity) 120 kwh/m 2.year Quality requirements Air Tightness: building envelope pressurization test result 0.6 air changes /hour (Building regulations 10 air changes /hour) Windows U-value 0.8 W/m 2 K ( not manufactured in UK at present! ) Quality Control of design and Certification All Energy demand values are calculated according to the Passive Hause Planning Package (PHPP) Certification of components and details
Energy uses comparison of standard and low energy houses
Comparison of heating costs and low energy houses with CO2 Emissions An investment in the future!
Summary Passive house is typically 80% more efficient that conventional houses for space heating. How does it work? 1. Insulation 2. Windows 3. Draft proofing 4. Ventilation 5. Thermal bridge
The crucial energy saving factor is invisible: Thermal Insulation Low effort, low cost high impact: the principle of thermal insulation U-values of 0.10-0.15 are required for thermal insulation of external building envelope
Spend the winter behind passive house windows Single glazing Double glazing Triple glazed windows U-value 5.0 W/m2K U-value 2.2 W/m2K U-value 0.8 W/m2K Walls U-value 0.1 W/m2K Windows are a major heat lose compared to walls.
Windows Thermal camera Single Glazing Triple Glazing
Draft Proofing / Air-Tightness Energy saving compliments mechanical ventilation
Whole House Mechanical Ventilation with Heat Recovery To get rid of carbon dioxide To prevent over heating by circulation and summer bypass To get rid of bad smells To get rid of moisture and prevent condensation
Ventilation System with Heat Recovery The Advantages 1. Automatically controlled supply of warm fresh air 2. energy efficient - 75% minimum of heat content of the exhaust air is recovered and supplied with the fresh air 3. Can be fitted with filters to remove dust and pollen inducing allergies and asthma 4. Windows can be kept safely closed to avoid noise disturbance and drafts in winter
Heat loss by Thermal Bridges Special attention must be given to the elimination of thermal bridges, particularly where walls meet foundations, floors, roof, and intersecting walls Thermal camera image highlighting heat lose at floor junction
Avoiding Thermal Bridges Passivhaus Eaves Detail
Thermal Bridge Analysis PHPP software need thermal bridges calculated! Isotherms Image Infrared Image
Benefits A Good Life for Everyone No freezing and no sweating. Enjoyable room temperatures between 20 and 23 C all year round Draw a deep breath - day and night Even allergy sufferers never run out of fresh air in a passive house Built-in safety to ensure long life The good air in the passive house prevents the formation of mould and thus structural damage into the distant future
Peace and quiet doesn't come easy......even in passive houses. Suitable for noisy location Quality and attention to detail Good Sound insulation
Snug and warm......with just 10 bulbs..
Energy Efficiency / running costs Space Heating It takes 10 light bulbs (100W) to heat 100sqm 2 in a passive house. It takes 200 light bulbs (100W) to heat 100sqm2 in a typical house.
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