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Parity Projects / A rational approach to retrofit advice

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Homes are responsible for around a quarter of the UK’s CO2 emissions, and about 80% of the homes that will be standing in 2050 are already built. But householders and social housing providers often find it difficult and confusing to work out how to achieve energy savings most efficiently and cost-effectively.

Parity helps households and social housing landlords solve these problems and increase the energy efficiency of their homes. The ‘Home Energy Masterplan’ service provides a report for individual households based on a detailed survey of their home and an interview to discover their objectives and how they use the property.

 Since 2006, Parity has undertaken nearly 700 home surveys

Savings of approximately 10 MWh/year (40%) per household

CO2 savings of about 3 tonnes/year per household

"A few people on the road have asked us about our solid wall insulation since it’s been installed; they want to know how it works and how they can do something similar."

Andrew Eagles, Sustainable Homes


The UK’s 23 million homes are responsible for around a quarter of the country’s CO2 emissions, and are some of the least energy efficient in Europe. About 80% of the homes that will be standing in 2050 are already built, so refurbishment of existing homes has a big role to play in reducing fuel bills and CO2 emissions. But householders often find it difficult and confusing to work out how to achieve energy savings most efficiently and cost-effectively for their individual property.

Parity Projects offers tailor-made advice and support services to homeowners, housing providers and the wider building industry looking to cut the energy use of the homes they own and manage. With an emphasis on evidence-based analysis, its reports recommend how to improve the energy performance of homes as effectively as possible in terms of cost, CO2 emissions reduction and disruption.

Ian Preston an associate surveyor for the Parity Project carries out an assessment of the external walls and roof

The organisation

Parity Projects Ltd (Parity) is a for-profit business founded in 2006 by Russell Smith, the Managing Director, when he was undertaking a major retrofit of his own home. The challenges he faced at that time in accessing the information he needed to make informed decisions led him to develop the service which is now core to Parity’s business.

It currently has eight members of staff and a network of over 20 associates. Sales in 2010/11 were £424,000, and Parity is currently experiencing annual growth of 40% in demand for its main products.

The programme

Many of Parity’s clients are already committed in principal to improving the energy efficiency of their properties but are not sure how best to go about it. Parity’s role is to inform and drive action, and to help ensure that the work is done cost effectively and strategically.

Parity has developed two software packages to produce their reports: for individual households, it has the ‘Home Energy Masterplan’ or HEM; and for social housing providers, the ‘Carbon Reduction Options for Housing Managers’ or CROHM. Parity also offers a project management service for any refurbishment work undertaken; and a building monitoring service for clients, to assess the success of their project and improve future performance. In addition to HEM and CROHM, Parity has developed a range of training courses in lowenergy refurbishment for tradespeople and professionals.

Ian Preston, an associate surveyor for Parity Projects, carries out an assessment of the external walls and roof

The services


Producing a HEM report is a multi-step process. First, a surveyor undertakes a detailed survey of the fabric of the building, and interviews the householder to understand their objectives for the project and the way they currently use their home. Surveys are carried out either by Parity staff or one of its freelance associates, who receive free training from Parity. The Parity in-house analysis team then use the HEM software to analyse the survey data and assess 30 to 50 individual retrofit measures, including the capital cost and energy, carbon and cost savings for each.

Ashden Award for Reducing Fuel Poverty


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This information is then presented to the householder in a rigorous but easy to use report. For simplicity, options are typically grouped under three different packages: ‘No Brainer’ (measures that have paybacks shorter than five years and cost less than £200); ‘Some Consideration’ (measures that have paybacks shorter than 15 years and cost less than £750 each); and ‘Green Halo’ (measures that have paybacks shorter than 25 years and cost less than £7,500 each). Tailored packages are also provided to reflect the specific objectives of the client, for example listing the most effective measures available for a given total budget.

Once the client has received their report, they are eligible for a free half-hour consultation with one of Parity’s retrofit experts, to clarify any questions they may have, and seek advice on the scheduling of their project. The latter is often particularly useful, since it can help a household identify where disruption and cost can be minimised. Both the pre- and post-survey interviews are a key part of Parity’s drive to understand clients’ current behaviour and to motivate behaviour change.

A large part of the survey is taking photos, lots of measurements and talking to the clients finding out any issues they have with the house, anything they want me to ask the analysts to look at.

Ian Preston, Associate Surveyor

What distinguishes the HEM service from many of its competitors is that it goes into more detail and uses a greater amount of data and analysis specific to the client, with a strong emphasis placed on how households use their homes and taking into account their budget and objectives. Where possible, it uses actual household energy use and retrofit prices that have either been quoted to the client direct or come from Parity’s database (which is regularly updated). The reports are independent: Parity is technology and supplier-neutral in its analysis.

Ashden Award for Sustainable Buildings

Greater London Authority

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The report generated by the HEM software can be branded for different audiences, so companies wanting to offer HEM directly to clients as part of their service can partner with Parity. Some partners use their own surveyors, and use Parity for the analysis, whereas others sub-contract the full service to Parity. Partners include architects, building companies, independent surveyors and energy advisers. The latest is the Ecology Building Society, which will offer HEM at a reduced rate to its customers.


The CROHM service uses a similar analytical approach to the individual HEM reports, but is targeted at clients that manage a large housing stock, allowing them to develop a strategic approach to the retrofit of their homes. The process also involves significant consultation with the client and other stakeholders. Pre- and post-report workshops are held in order to properly understand the housing stock, residents’ needs, other programmes of work that are underway or planned, and what in-house contractors are able to deliver. These workshops are delivered in partnership with Sustainable Homes, a sustainability training and consultancy adviser that provides advice to housing associations on cutting CO2 emissions and tackling fuel poverty.

A newly retrofitted house

As with HEMs, the report produced is rigorous but accessible, providing detailed recommendations for the housing stock based on an analysis of actual client data. Again, it is tailored to meet the housing provider’s specific needs and goals, and includes, for example, installation costs specific to their contractors. With the Green Deal set to launch later in 2012, there is an increasing demand for this kind of strategic assessment of retrofit potential.

The software used to produce both HEM and CROHM reports is constantly updated and improved to meet customer requirements and industry standards, and to reflect new data and experience.


Training is a key aspect of Parity’s services. It offers a range of one-day, BTEC accredited training courses, covering general techniques for low-energy refurbishment, which are the first of their kind in the UK. These are run both as open courses and in-house, and integrate closely with other services – for example, social housing staff and contractors sometimes attend to help them understand and plan the programme of work recommended by CROHM. Many of the freelance associates Parity uses are also recruited from those who have attended its training courses.

We wanted a more efficient house and when we spoke to Parity we felt we were speaking the same language. The energy survey really ticked the boxes of what we were looking for.

Nicholas and Rachna Lévêque, Parity Project customers

Parity has recently partnered with the training body EAL to deliver a new five day Level 2 qualification, ‘Understanding Sustainable Refurbishment’, designed to help contractors and other professionals (energy advisers, architects and building control officers) establish themselves in the property retrofit market as it grows over the next few years.

How much does it cost?

Parity charges from £290 for a HEM, with prices for CROHM varying significantly according to the size of the housing stock and the availability of data. The training courses vary in cost starting at £120 + VAT for a one day course.

Parity’s project management fees vary according to the job, but are typically 10-15% of the total cost. The cost of the building monitoring service is highly dependent on the requirements of the client.

Promotion and monitoring of product

Parity markets its services primarily through partners, press coverage and by giving talks and presentations to bring in business and build its brand and reputation. Clients also arrive via the internet and social media, with Parity’s twitter feed having over 1,200 followers. Housing stock assessment clients typically arrive either through word of mouth, attendance at events or via partners.

It’s important that we practice what we preach so that we understand what will be applicable to each household.

Chris Newman, Commercial Director, Parity Projects

There is currently roughly a 50% conversion rate between enquiries and HEMs. Some drop out due to the cost, and Parity has plans to introduce a ‘HEM light’ version.


Since 2006, Parity has undertaken nearly 700 surveys of individual homes and 17 largescale stock assessments for housing providers covering more than 240,000 homes. It has run training courses for approximately 500 students and installed around 190 monitoring systems for 20 clients.

Approximately 90% of clients who complete the Parity feedback form state that they intend to take up at least some of the measures recommended in the report. However, Parity does not currently follow up clients to find out how many measures have actually been installed because of the high administration costs involved. Assuming that half of the properties surveyed as part of HEM and half the properties surveyed as part of CROHM (10% for local authorities) go on to be refurbished in some way, then Parity’s work programme has benefitted about 57,000 households (131,000 individuals). However, this estimate is very approximate.

Environmental benefits

Parity’s activities have catalysed approximate savings of 10 MWh/year (40%) per household as a result of HEM reports, and 31,000 MWh/year per CROHM client, assuming Parity’s recommendations lead to the take up of all ‘Some consideration’ measures for HEMs; and 50% of recommended cost effective measures for social landlords (10% for local authorities) in CROHM reports. These figures as based on estimates, as it is difficult to keep track of exactly which measures clients implement in their homes or housing stock.

Nicholas & Rachna Leveque are the home owners that have requested a survey from the Parity Projects to determine their energy use

This represents savings of 3 tonnes/year of CO2 per household for a HEM report and nearly 9,000 tonnes/year of CO2 per client using the CROHM service. These figures use a conversion factor or 0.2777kg CO2 /kWh, assuming 75% of the saving is gas and 25% electricity.

Social benefits

By offering a straightforward and user-friendly advice and management service, Parity motivates people who would like to take action on improving the energy efficiency of their homes to actually take it, making retrofit seem eminently ‘do-able’.

The CROHM service is often focussed on helping social landlords find cost effective measures to reduce fuel poverty amongst their tenants. HEMs are aimed at individual householders, but have also been widely used by community groups in exemplar projects and education programmes. Parity’s knowledge of retrofit has also been shared widely in the community through regular public talks and presentations.

Economic and employment benefits

Parity’s clients are making savings on their energy bills as a result of taking up options recommended in HEM reports. The average payback periods range from under two years for the ‘No Brainer’ options to just under 12 years for some of the ‘Green Halo’ options – see box for more information.

The training offered by Parity focuses on the opportunities for new work in the retrofit market, and as such helps people at all levels and with a variety of specialisms to enter this field of employment. Similarly, Parity’s free HEM surveyor training has enabled a growing number of freelance individuals (currently 23 active, with a further 10 in training) to offer a new service or develop their own businesses.

A customer in newly retrofitted home

Through their partnership with Parity, other organisations (such as architects and building companies) are able to use HEM to strengthen and broaden the services they can offer to their own clients.

Potential for growth and replication

A large part of the future market for Parity is likely to be through the Green Deal, probably from working as technical partners with the major Green Deal providers and establishing a platform through which SMEs can participate in the Green Deal market. The Green Deal also represents a significant business opportunity for Parity in social housing, as providers will need support services in preparing and implementing the retrofit of their stock.

Parity is looking at developing its HEM service to offer a cheaper ‘entry level’ product for those wanting less detail at a lower cost, and a more expensive ‘gold’ service for those wanting on-going dialogue and support. Longer-term, Parity also plans to make its software available online so that it can be accessed more widely.

To improve monitoring, Parity plans to introduce a random survey for householders, and an annual follow-up for CROHM clients. It aims to offer its HEM service (directly and through partnerships) to at least 5-10% of UK households over the next 10 years, and to offer its CROHM service to about 10% of the 1,200 residential social landlords in the UK over the next five years.

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