Future Of Passivhaus In The Uk Construction Essay

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This chapter will look at Code level 6 homes (zero carbon) and Passivhaus homes and compare them to standard new build homes in terms of construction cost and what savings will be achieved from energy efficient performance. This will then be looked at in contrast to the findings of the previous chapter in terms of public opinion about additional expenditure on zero carbon homes.

As you can see from the table, total costs between each level roughly doubles. Costs are mainly incurred from meeting energy requirements for the Code, but of course meeting these requirements will reduce the energy demand of the building and therefore reduce running costs. The costs at Code level 6 do not take into account the benefit of zero stamp duty associated with achieving the zero carbon standard, if these were included it could reduce costs (assuming all of the benefit were to accrue to the house builder) by up to £15k per home, depending on sale price (DCLG 2008). If the cost differential between level 5 and 6 is less than the level of stamp duty avoided, then it would be more cost effective to build to Code level 6 than Code level 5.

A recently completed British Passivhaus has been built using cavity wall construction. The Denby Dale Passivhaus is a three bed detached dwelling built in West Yorkshire. The project managers and contractors were Green Building Store who worked with architect Derrie O'Sullivan and energy consultants Peter Warm Associates. Using cavity wall construction means that it blends in with the design of surrounding houses by using a similar cladding (and also complies with planning restrictions put in place in the area). Using this principal in future projects would mean the public will be more trusting of the design (as they are used to this style of building) and are more likely to consider a Passivhaus design. The build costs for the project came to £141,000 (Green Building Store, 2010). A similar sized, nil-rated home in the same area would have construction costs of around £120,000.

From the Survey we learnt that it would be most profitably for house builders to charge £7,500 extra for houses that achieve zero carbon as this would receive the highest levels of public interest. From these results though we can see that this figure is totally unrealistic as the increase in build costs for a Passivhaus are nearly three times this amount and more than five times this amount for zero carbon homes. Again the results do not take into account the reduction in stamp duty that the homes will receive but the increase in cost is still likely to be higher than that derived from the survey. However if all the benefits of having a highly energy efficient house were fully explained to the public and they were shown the year on year savings that they are likely to receive from having a house that performs so well, then it is extremely probable that they would be willing to spend more initially on the building. This will always depend on the individual customer though because most people are restricted by what they can borrow from banks and building societies. However, it is likely that building societies will lend more when the customer is buying a Passivhaus or zero carbon home as this means their disposable income will be increased due to smaller energy bills and therefore should be able to repay the mortgage quicker.

As you can see from the graph after the first few initial projects where the buildings were tested, results collected and the performance levels were proved, the number of completed projects in Germany began to rise quite rapidly. This also happened after the foundation of the Passivhaus Institut in 1996 and the creation of the PHPP in 1998. PHPP software and handbook was not translated into English until 2004 which has greatly restricted the growth of the standard within English speaking countries. In 2006 there were approximately 6000 completed Passivhaus projects completed in Europe (Grad School, 2006) and there are currently around 17,000 completed projects Worldwide (Sara Fakhro, 2010).

Although Passivhaus is likely to become widely implemented across the UK there are a number of factors which may slow the development of the standard across Britain. These may influence the future of the technique and mean that it evolves to meet the needs of British builders and customers.

The first problem, that is already being constantly improved, is that there is technical literature produced about Passivhaus that has yet to be translated into English, there are also building products that are not readily available in the UK. Another issue is that of consumer aspirations, people expect to have central heating and want fire places as well as traditional looking buildings with cavity wall construction (which of course is possible but requires extra planning and extra care during construction).

House builders will take time to get used to using the technique and its associated planning and calculation software. It also requires extremely high levels of onsite build quality and failure to check for continuous airtight barrier on plans can lead to major problems which may be very expensive to put right. Builders will have to learn new skills and site practices to ensure standards are met.

Existing building standards and policies, if not altered, may make it hard both physically and financially to comply with the Passivhaus technique. In certain areas planning and conservation legislation may also create problems when trying to implement the newer, less traditional, building design.

Chapter Summary

This chapter shows that increased building costs encountered when building to the Passivhaus standard are similar to that of comparable Code levels. This means that it should be financially possible for Passivhaus to be implemented throughout the UK although an explanation to possible customers of the savings that will be achieved from having a highly energy efficient house may be necessary in order to make sales. It has also been shown that Passivhaus has grown every year since conception and the number of projects that have been completed has increased quite rapidly since around the year 2000. It is likely that the initial application of Passivhaus in the UK may be slow as there are a number of issues that need to be addressed. But as these problems are fixed and Passivhaus becomes more common, the standard may see rapid growth.