Copyright ©2008/2009 Zero-Carbon Solutions Ltd IntroductiontoPassivehouses - or “Obsolete House vs Passivehouses” Introduction to Passivehouses - or “Obsolete.

Copyright ©2008/2009 Zero-Carbon Solutions Ltd

IntroductionIntroduction toto Passivehouses - orPassivehouses - or“Obsolete House vs Passivehouses”“Obsolete House vs Passivehouses”

Niels J Bjergstrom, MSc/PhD (Civ. Ing.)

Director & Passivehouse Planner

Zero-Carbon Solutions Ltd


UK Final Energy Consumption

• Domestic Energy Consumption (DEC) has been fairly constant since 1995 and accounts for a bit over 30% of the nation’s CO2 emissions

• 2006 is slightly lower, probably due to the mild winter

• Sharpened building regulations and other measures have not (yet) produced a reduction in DEC

• A puny 0.7% of the DEC came from renewable sources in 2006

• Largely inefficiently produced electricity, contrary to this, accounted for 22% - the rest came from gas

1Services include agriculture

Source: UK Energy in Brief, July 2007 (DBERR)


Distribution of Domestic Energy Consumption• Lighting and appliances show a slightly increasing

trend corresponding to the technologisation of dwellings

• Energy used for cooking and water is roughly constant

• Energy used for space heating shows an unbroken increase with the consumption roughly doubling every 70 years

• Why?– UK housing stock is the worst quality in Northern

Europe with 7.5% officially classified as unfit– Political impotence and incompetence - neither sticks

nor carrots to promote low-energy renovation– New-built dwellings in the UK show rates of pollution

and energy use 4-5 times as high as those built in Europe

– Planning and conservation policies prevent healthy and energy efficient dwellings from being built by preventing natural decommission and replacement

• In short: ‘green’ housing is held back by unsuitable legislation and stifling conflicts of interestSource: BERR based on BRE Data

Despite that we need to reduce the amount of energy used for space heating radically, both in new and existing buildings - this is more important than fixing the supply side: don’t generate more energy - use less!

This is where public money and fiscal and planning policies should be directed,not to the large energy generators and oil producers.


Obsolete House

Average UK domestic dwelling, probably in fact better than average. Figures presented correspond to 1995 building regulations or so.

Houses built to current building regulations are (supposed to be) around 20-25% better energetically but the technology and quality control measures to accomplish this are not in widespread use.

A typical pre-1950 dwelling causes annual carbon emissions of around 7-8 tons, just to keep the house warm(ish). New builds are not much better, using 3-4 times as much heating energy as a modern European dwelling, which emits less than 1 ton of CO2 annually.

The UK housing stock is the worst in Northern Europe with about 7.5% (over 1.5 million homes) officially classified as unfit as dwellings (although mostly still in use as such), causing unnecessary deaths and disease.


Passivehouse

A passivehouse is a building constructed to the contemporary passivehouse standard in a well defined and verifiable way, using well-known technologies, procedures and components.

This standard is originally Scandinavian and corresponds quite closely to building regulation requirements in one of the Swedish climate zones (the first zero carbon house was built near Copenhagen in 1976 by Danish architect Vagn Korsgaard).

The method was brought to Germany from Sweden and expanded by Dr. Wolfgang Feist, founder of the Passivhaus Institute in Darmstadt. For this reason some people use the German word for passivehouse, Passivhaus.

It is important to understand that a passivehouse is just a normal modern house, correctly designed and erected, scientifically calculated and verified during and after completion. It does not really illustrate how radical European builders are but rather how far behind the UK construction industry is.

No witchcraft is involved (and it is all right to open the windows).


Obsolete House vs Passivehouse

Poor insulation

Super-insulatedU ≈≈0.15 W/m2K



Poor insulation Super-insulatedU ≈≈0.15 W/m2K

Frequentlycold bridges

Avoidance ofcold bridgesby designΨ≤≤0.01 W/mK



Poor insulation Super-insulatedU ≈≈0.15 W/m2KFrequently

cold bridges Avoidance ofcold bridgesby designΨ ≤≤0.01 W/mK

Uncontrolledair infiltration

Airtightenvelope,n50< 0.6h-1

Inappropriateventilationstrategies

Controlledventilation






Airtight envelope,n50< 0.6h-1



Single or doublewindow panes inthin and leakyframesresult incold radiation

and draught

Passivehousewindows,triple-glazingand super-insulatedframesUg ≤≤0.7W/m2K1.6g (W/m2K) ≥≥Ug

Uf ≤≤0.8W/m2K









Single or doublewindow panes in thinand leaky framesresult in cold radiationand draught

Passivehouse windows,triple-glazing and super-insulated framesUg ≤≤0.7W/m2K1.6g (W/m2K) ≥≥Ug

Uf ≤≤0.8W/m2K

Solar Gainsnot consideredin design process

Orientation onplot and glazingdesigned to providesome 40% of heatingrequirements frompassive solar gains











Uf ≤≤0.8W/m2K


Orientation on plotand glazing designed toprovide some 40% ofheating requirementsfrom passive solar gains

Resultant space heatingrequirements:

> 100W/m2 < 10W/m2











Uf ≤≤0.8W/m2K



Draughty heatingusing radiatorsbelow windows

Heat added toinjected fresh airat low temperature,causing no draught

Uneconomicheating system,10kW or more

Advanced heat recovery system with small air heater, max. 1kW

> 100W/m2 < 10W/m2


Obsolete House vs PassivehousePoor insulation Super-insulated

U ≈≈0.15 W/m2KFrequentlycold bridges Avoidance of

cold bridgesby designΨ ≤≤0.01 W/mK







Uf ≤≤0.8W/m2K



Draughty heatingusing radiatorsbelow windows

Heat added toinjected fresh airat low temperature,causing no draught

Uneconomicheating system,10kW or more

Advanced heat recovery system with small air heater, max. 1kW

Typical annualenergy consumptionfor space heating:

160kWh/m2a

14kWh/m2a

Savings> 90% !!


Passivehouse Certification Criteria

Criterion Required value How to attain Space heating demand as calculated by PHPP

< 15kWh/m2a Careful design using passivehouse construction techniques and components – precise and complete specifications – cold bridges! Accurate research and establishment of climate data for the construction site Iterative energy calculations using PHPP Correct placement of the building on the site to maximize solar gains and minimize winter shading – situation and orientation Excellent work force, training and site management Unrelenting quality control from design to finished project

Airtightness n50 ≤ 0.6h-1 Design for airtightness Make drawings clearly showing all transitions and difficult spots Use suitable materials, particularly adhesive tapes Test as soon as possible to avoid costly repairs – use the ventilation system if possible, otherwise a blower door

Primary energy consumption < 120kWh/m2a (expected to fall to 100kWh/m2a)

Use low-energy appliances Carefully plan water heating system Use free and ultra-low energy sources as much as possible – solar panels, PV, heat pumps

Overheating frequency, number of days annually where room temperature exceeds 25°C

Not currently specified

Use shading elements as required: permanent, adjustable or seasonable Careful design of fenestration, ventilation system and internal airflow

Cooling characteristics and load – cooling demand

< 15kWh/m2a Design shading and ventilation to minimize cooling requirements


Obsolete House vs PassivehouseExpensive to heat and maintain Inexpensive to heat and maintain

Uncomfortable to live in:• large temperature differences between windows and walls, etc• large temperature differences between heating elements and surroundings - hence always draughty

Ultra-comfortable to live in:• low temperature differences between windows and walls, etc• low-temperature additional heating - hence never draughty

Propensity to humidity because of infiltration of humid air and poorly designed ventilation strategies - leads to health problems and costly damage

Dry, comfortable and healthy. The ventilation system assures a constant supply of clean, warm and, if required, pollen-free air.The ventilation and heating strategy makes passivehouses uniquely suited for schools, care homes and other health care units

Comparatively cheap to build with high and increasing running costs - falling resale value

Higher initial costs, low running costs and lower total life cycle costs (e.g. over 40 years) - high and increasing resale value

Relatively easy to build - limited planning and quality control effort, based on ‘approved’ techniques and solutions, and traditional methods; normally erected on site using labour with little training and varying motivation

More difficult to build correctly - requires exact and detailed design, planning, specifications and calculations; trained, motivated and well managed on-site craftsmen. Off-site manufacturing an advantage

Probably impossible to get to zero carbon

Can be taken to zero carbon with additional design effort and cost


ImportantThe passivehouse standard does not dictate:

Aesthetics Architectural freedom is hardly limited by passivehouse requirements although some types of visual and functional solutions need to be constructed differently from habit.The work process is altered considerably, though: architects cannot design passivehouses the way they have been used to design traditional buildings. All passivehouses are designed scientifically and calculated individually. For this reason, normally the smallest unit that can design passivehouses consists of an architect and a passivehouse planner (engineer).All passivehouses undergo comprehensive quality control and verification, a process which starts from the very first parts of the planning and design stages, hence the passivehouse planner must be involved from the very first stages through to project delivery.

Choice of materials Should your favourite planning authority in their inscrutable wisdom decide that your new passivehouse must look like a Cotswolds cottage and use the corresponding stones and tiles this is not impossible. It does not even need to be more expensive or difficult to realise than any other passivehouse construction. Passivehouses can be built to fit into just about any neighbourhood or area.

Construction technique Passivehouses can be constructed using most usual construction techniques: timber frame, masonry, stone or concrete. It is fair to say, though, that the larger a percentage of the construction that can be carried out off-site under stringent quality control, the greater the chance of getting a satisfactory result.

Energy All types of energy supplies, water heating techniques and appliances can be employed in a passivehouse as long as they fulfil energy requirements. Typically, techniques such as heat pumps, solar collectors, photovoltaics, district power and micro-generation would come into play. Taking the step from passive to zero-carbon (a huge step) requires careful energy planning.


ImportantWe have not talked about:

Ecological Considerations

The passivehouse standard does not include sustainability considerations as a verifiable part of the standard.The standard, however, fits like hand-in-glove with the current UK trends regarding sustainability in construction, the Code for Sustainable Homes.It is important to note, however, that SAP 2009 with associated appendices is not required in order to calculate passivehouses, and it will in all probability not do so correctly. It is particularly worrying if components like those listed in Appendix Q, get mixed up with components suitable for use in passivehouse construction!

Economy Setting up comparative calculations between obsolete houses and passivehouses lies outside the scope of this brief presentation.This has been done in several countries and climates, and these calculations demonstrate conclusively that even with a flat energy price development passivehouses are cheaper over the projected life cycle of the building. Increasing energy prices will enhance the return of course.

Town planning Passivehouses give greater comfort, a higher return on investment and a better ecological outcome if they are situated correctly in relation to their environments.This means that passivehouse developments should be laid out to optimise solar gains, minimise and regulate shading and enable local sustainable energy generation and distribution.

Practicalities Passivehouses are more difficult to get right than obsolete buildings, mainly because the latter are not specified and verified objectively. To produce passivehouses you need to take care throughout the design and production process, you need proper QC from day 1 and you need verification on the ground of design criteria versus results. You cannot for example carry out airtightness test on a few samples in a large development as proposed in the building regulations - these tests must verify the quality of each individual building.

Renovation work Outside the scope of this presentation - but the Standard and methods are very well suited.


Questions?

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Thank you!

Zero-Carbon Solutions Ltd provides:

•passivehouse planning, surveying and engineering services, e.g. to architects•full passivehouse design and planning services (domestic and non-domestic)•renovation and restoration projects to near passive standard•energy calculations: PHPP, sBEM, SAP, simulations, etc•climate data and software: Meteonorm•project and site management•training and education•off-site manufacture•turn-key projects: schools, care homes, office buildings•small (domestic size) passivehouses as envelopes or turn-key

[email protected] - http://www.zerocarbonsolutions.com

Copyright ©2008/2009 Zero-Carbon Solutions Ltd IntroductiontoPassivehouses - or “Obsolete House vs Passivehouses” Introduction to Passivehouses - or “Obsolete.

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