Passivhaus – The Answer to Building Carbon Emissions Reduction and Fuel Poverty?

                                           Denby Dale Passivhaus - first certified cavity wall constructed passivhaus in the world

If asked whether you would be interested in living in a house where the heating energy use was between 10-25% of what it is now, with correspondingly lower bills, that was a very pleasant and comfortable abode and didn’t require a conventional heating system, would you be interested?

If the answer is yes then you would be interested in a Passive House or Passivhaus as the German originators call it.

With the UK’s self imposed target of an 80% reduction in carbon emissions from buildings by 2050 and the ever increasing numbers of households falling into fuel poverty because of rising energy bills, coupled with having the least thermally efficient housing stock in Europe, there is a desperate need in the UK to improve the thermal efficiency of all our buildings to combat these two drivers. Let alone the requirement to reduce our demand for fossil fuels sourced from increasingly politically agitated parts of the world and become more energy secure.

By 2020 all new buildings (not just houses) in Germany and Austria will be designed as Passivhaus. Some experts believe that the standards may be adopted as a compulsory standard throughout the EU.

There are moves afoot that may see houses built to the Passivhaus standard automatically complying with Part L of the Building Regulations.

In the UK the historical idea of a passive house is one that is oriented towards the South, makes the optimum use of solar gain, with large south facing windows or atria and smaller north facing openings, apart from that it is a conventional build.

The German Passivhaus does make use of that detail but it builds on the concept of improving the fabric first, so Passive Houses are:

• Super insulated, nominally U values of 0.15 W/(m2K) or lower for walls, floors and roofs, so insulation thickness is usually 300mm depth or greater.
• Reduced Thermal bridges, ? = 0.01 W/(mK), so thermal breaks to prevent heat flow from inside to outside, e.g. canopies and balconies are self supporting structures not connected to external walls
• Improved airtightness, maximum 0.6 air changes per hour, so care is taken over all penetrations for services, all joints are taped or have wet plaster to make a complete airtight layer within the insulation layer
• Good quality windows and doors, U values of 0.8 W/(m2K) or lower, usually triple glazed, designed so that the solar gain is more than that lost through the glazing, in effect they become net radiators of heat throughout the year
• Comfortable to live in, well ventilated with no draughts as there is no requirement for convective heating systems e.g. no radiators under windows, there are none of the draughts associated with the convective heat currents they produce
• No conventional heating system but Mechanical Ventilation with Heat Recovery (MVHR) instead. Over 80% of the heat produced within the dwelling through the occupants, lights and appliances is recovered through a heat exchanger that removes the majority of the heat from extracted air and transfers it to filtered, fresh, incoming air.

In practise this means that houses are designed to only need 15 kWh/m2 per year for heating.  This is the same as a heating load of 10 W/m2, equivalent to the heat from one lit candle every square metre of floor space! In addition the design for primary energy demand including electricity for lights and appliances is 120 kWh/m2 per year.
 
The internal temperature is designed for 20?C throughout and a temperature of 25?C shall not be exceeded for more than 10% of the year, with most designers aiming for a target of 5%. It has been proven that Passive Houses will not fall below 16?C even without heating in the coldest winter months.

Houses do need a small boiler or equivalent to provide hot water and this can be offset through the use of a solar thermal system.

Passivhaus designs are analogous to the energy requirements with the Code for Sustainable Homes Levels 4/5, however there is no fundamental requirement for on site renewables, though these can be incorporated and would reduce the Primary Energy Demand even further.

You are wondering how much this adds to the cost of a house.  The Passivhaus design does cost more to build, with additional materials, different ways of construction and a specially trained workforce, though in Germany the costs are proving to be equivalent to or even lower than conventional new build. When life cycle costs are included there are significant savings for householders through reduced running costs and with energy bills expected to rise by an annual average of 9% per annum for the foreseeable future, the economics of a Passivhaus are even better.

This is great for new build but what about existing properties I hear you say. Between 75-90% of the houses built now will still be around in 2050.

The Passive House Institute have developed a Passivhaus standard called Enerphit for retrofits. They recognised that it is not always possible to achieve the full Passive House standard for modernising old buildings so they have slightly reduced the criteria but it is still based on the principles of excellent thermal performance, exceptional airtightness and mechanical ventilation with heat recovery.

In the UK Certified European Passive House (CEPH) Designers or Consultants have to undergo training that at the moment is only offered through the BRE, University of Strathclyde or the Association of Environmentally Conscious Builders.  The BRE have identified the course and associated exam as the most challenging that they offer.  It is certified by the Passivhaus Institute in Darmstadt, Germany where the standard was developed.  The exams are offered 4 times a year and all students have to sit the same exam, at the same time throughout the world.

On passing delegates are able to label themselves as Passive House Designers or Consultants.  In the UK at the moment there are less than 100 who are Certified.

Passivhaus is the fastest growing energy performance standard in the world with 30,000 buildings realised to date, the majority of those since 2000.

The Passivhaus Standard can be applied to any climate in the world and works equally as well in warm climates as it does in more moderate climates. To date Passivhaus buildings have been designed and built in every European country, Australia, China, Japan, Canada the USA and South America....a research station has even been constructed to the Passivhaus Standard in Antarctica!

So coming to a street near you soon, Passivhaus.

If you are interested in a Passive House Approach then please contact Peter Chisnall, Certified Passive House Consultant 150711, on 01376 531531

  Adam Dadeby House Devon
           

Suzanne Lacey, Renewable Energy Manager Recent changes to Feed in Tariffs (FITS) and the introduction of the Renewable Heat Incentive (RHI)

Suzanne Lacey, Renewable Energy Manager for Climate Energy Limited explains the recent announcements about the FITs and the imminent RHI.

The Government Spending Review in October 2010 proposed changes to the FITs which would create savings of £40m, or 10% of the FIT budget allowance for 2014-15. The first comprehensive review of the FITs has been brought forward and began on 7th Feb 2011 (two years early). This review will examine all aspects of the scheme and assess the best way to deliver the £40m saving in 2014-15. The Government is currently seeking views on the changes and consultation (when it is issued) will close on 12th April 2011. The review will be completed by the end of 2011 with no tariff changes being made to small scale installations until April 2012 (unless the review reveals a need for greater urgency than that).

Additionally, there will be a "fast track" review of the tariff rates for solar farms and anaerobic digestion plants (AD). The concern here is twofold. First that a few investors would make large amounts of profit out of solar farms, whilst at the same time gobbling up available money which was supposed to incentivise householders, businesses and communities to become involved in renewable energy generation. Second the Government expected greater investment in AD plants.

On 18th March 2011 the Government announced a proposal to significantly reduce the tariff levels for PV arrays larger than 50kW and increase the tariffs for AD plants. These changes, if implemented, will take an effect on 1st August and will impact on customers wanting to install large PV arrays on industrial units, large office or tower blocks, leisure centres and similar buildings. These clients would be best advised to get their projects through planning and installed before that date. However, it is important to realise that these changes are not yet set in stone - since the Government is out to consultation until 6th May 2011 and the results won't be finalised until after then.

Retail Price Index (RPI) adjustment

The RPI adjustment to the FITs rates has been announced. All tariffs will increase in line with inflation by 4.8% on the 1st April 2011. This takes the export tariff to 3.1p per unit, and the rate for domestic PV from 41.3p per unit to 43.3p per unit.

RHI

During the 2010 spending review the chancellor announced £860 million of funding for the RHI, which will be introduced from 2011-12. This is 20% less than previously proposed and comes directly from DECC’s budget and not from a levy on fuel bills. The UK is the first country to implement a fiscal reward scheme for renewable heat generation, and the scheme is designed to enable us to meet our renewable generation targets of 15% by 2020. The scheme will be introduced in two phases, as follows:

Phase one - This part of the scheme is set to launch in October 2011.

Long-term tariff support for commercial, industrial and public sectors, as well as community and not-for-profit groups. This support is aimed at the largest users of heat and the biggest contributors to emissions from heat. Technologies include solid and gaseous biomass, solar thermal, ground and water source heat-pumps, on-site biogas, deep geothermal, energy from waste and injection of biomethane into the grid.

Premium Payments – these are one off payments made for domestic installations of biomass, heat pumps (ground, water and air source) and solar thermal. In return for this payment the Government will require monitoring and feedback about how these installations work in practice – so that they can work out the best long term tariffs for each technology. The homeowner will need to have a well insulated home (based on its energy performance certificate) to qualify, and there will be a focus on people living off the gas grid, where fossil fuels, like heating oil, are both more expensive and have higher carbon content.

Phase two – October 2012

Assuming domestic technologies are cost effective they will become eligible for RHI long term tariffs in October 2012. This will coincide with the Green Deal – and we hope that the Green Deal will provide the up front capital in the form of a loan to enable householders to buy renewable heat technologies and then the RHI to help them repay the loan. More information is expected imminently.

To find out more about the changes to FITs and the RHI please visit the DECC website:http://www.decc.gov.uk/