House Exchange started life as a local mutual exchange database for housing tenants in and around Norwich. 101 approached Clarion with the idea of making it a national system and the joint venture was formed. At the time the only similar system was a government sponsored project which unwieldy and unloved. Today the system is directly supported by around 200 landlords whose tenants use the system free of charge together with thousands of tenants from other landlords who pay a small fee.
The system is very firmly in the public sector, in 2010 House Exchange were part of a group brought together by the department of Communities and Local Government to discuss how competitive systems could work together to improve the opportunities for tenants to find a mutual exchange and to move from a paid service to a 'payment by results,' service. 101 and House Exchange have supplied technical solutions that have been adopted in both cases.
House Exchange in essence is a dating agency, it puts people with matching characteristics in touch with each other. In this case though it is not about a shared passion for pigeon racing and a good sense of humour but what is your current property type, location, how many bedrooms, rent, parking, garden, double glazing etc. In addition, tenants provide a specification of where they want to move to in terms of property type, bedrooms etc. and crucially, location.
From this data it is fairly easily match most characteristics, however, location matching is not straightforward and to do it across tens of thousands of candidates in real time is a significant challenge. The system also needs to have a completely separate administration interface to allow landlords to manage their tenants using the system.
There are essentially 4 websites associated with House Exchange, a complete system to allow new users to try the service together with related pages about how it works. The second version is the main system used by the majority of visitors after they have logged in. A third system allows landlords to review what their tenants are doing and operate the system on behalf of tenants who do not have online access. The fourth system is for Clarion and 101 administrators to manage the site content and to some extent the landlord clients.
The heart of the site is the matching of tenants with others so that a mutual exchange is possible. In most cases this is a direct match where the tenants swap with each other. In these cases, we have created new geographic techniques to make searching fast enough for real time operation. Competing systems do their matching offline and restrict access only to the lists compiled overnight. Unlike our system new properties aren't available until a new list is compiled.
The techniques used in the system are so powerful that we were able to offer a whole new search option where tenants can investigate a 3-way chain of matches. In this situation the tenants can review a list of properties they could move into and lists of possible 3-way chains. In this scenario the search complexity is multiplied by several orders of magnitude but we are still able to do this real time.
The administration system is also able to offer landlords an insight into which of their tenants are over or under occupied and whether they are looking to upsize or downsize. In some crowded inner-city boroughs this information allows them to target tenants, usually with incentives, to better align property sizes with family sizes.
The system also inspects all new registrations to alert existing users if new properties come onto the system that match their details, again this is done in real time throughout the day. In recent times the system has also had a mobile App created to let people check easily via their phones if new property is available.