Frequent questions

The HouseMetric website is a side project of mine. I created the site initially as a way to teach myself web development as a hobby and also because I wanted to see the data and graphs to help with my own personal home sale and purchase decisions. I put it online as a free to use resource for anyone else with the same analytical interests as me. I'm adding more features as and when I have time so please come back every now and then to see what is new.

Sept 2024 update: A few months ago I started charging for the features that cost me a lot in server costs. I am almost there in terms of covering the Amazon web hosting costs, so please help spread the word about it. The more people that use it the more time I'll spend on it adding extra data.

Internal area data is primarily taken from a property's Energy Performance Certificate (EPC). Sometimes there are multiple EPC inspections, if you navigate to the individual property page you'll be able to see the different data reported from each of these EPC visits. We try to show the property size given in the most recent EPC. Energy Performance Certificate (EPC) data is licensed under the Open Government Licence v3.0.

Price paid data comes from HM Land Registry data Crown copyright and database right 2024. This data is licensed under the Open Government Licence v3.0 (OGL). However the Price Paid Data also contains address data processed against Ordnance Survey's AddressBase Premium product, which incorporates Royal Mail's PAF Address Data. Royal Mail and Ordnance Survey permit the display of Address Data in the Price Paid Data for the purpose of providing residential property price information services. However the OGL does not cover the use of these third party rights.

If you see an error in the Land Registry data you can report it to Land Registry via: https://customerhelp.landregistry.gov.uk/changeasalesrecordwebform/ and once they put out the change this website will automatically update.

Plot outlines are also from Land Registy. They are only indicative of the location and approximate size and shape of Land Registry registered freehold land. They have no legal status. The polygons (including the associated geometry, namely x, y co-ordinates) are subject to Crown copyright and database rights 2024 Ordnance Survey.

The Price Paid Data from Land Registry is typically updated on a monthly basis. It was last updated on 2024-11-1 and contains sales up to the end of September 2024. Bear in mind these sales trickle in so it takes about 6 months to get 95% of the data. I'll write a blog post on it when I get around to building a blog.

Energy Performance Certificates (EPC data) is obtained from the Ministry of Housing, Communities & Local Government.
The Energy Performance Certificates dataset was last updated 2024-11-1 as well.

Inspection date

The date that the inspection was actually carried out by the energy assessor

Reason for EPC

Type of transaction that triggered EPC. For example, one of: marketed sale; non-marketed sale; new-dwelling; rental; not sale or rental; assessment for Green Deal; following Green Deal; FIT application; none of the above; RHI application; ECO assessment. Where the reason for the assessment is unknown by the energy assessor the transaction type will be recorded as 'none of the above'. Transaction types may be changed over time.

Tenure

Describes the tenure type of the property. One of: Owner-occupied; Rented (social); Rented (private) Rented (social) Rented (private) Owner-occupied NA (new build)

Habitable rooms

Habitable rooms include any living room, sitting room, dining room, bedroom, study and similar; and also a non-separated conservatory. A kitchen/diner having a discrete seating area (with space for a table and four chairs) also counts as a habitable room. A non-separated conservatory adds to the habitable room count if it has an internal quality door between it and the dwelling. Excluded from the room count are any room used solely as a kitchen, utility room, bathroom, cloakroom, en-suite accommodation and similar and any hallway, stairs or landing; and also any room not having a window.

Year built

Age band when building part constructed. England & Wales only. Typically one of: before 1900; 1900-1929; 1930-1949; 1950-1966; 1967-1975; 1976-1982; 1983-1990; 1991-1995; 1996-2002; 2003-2006; 2007-2011; 2012 onwards.

Area

The total useful floor area is the total of all enclosed spaces measured to the internal face of the external walls, i.e. the gross floor area as measured in accordance with the guidance issued from time to time by the Royal Institute of Chartered Surveyors or by a body replacing that institution. (m²)

EPC Grade

Current energy rating converted into a linear 'A to G' rating (where A is the most energy efficient and G is the least energy efficient)

The heatmap of property prices uses Land Registry INSPIRE Index Polygons, an open source dataset. This information is subject to Crown copyright and database rights and is reproduced with the permission of HM Land Registry. The polygons (including the associated geometry, namely x, y co-ordinates) are subject to Crown copyright and database rights Ordnance Survey 100026316. Here is a link to the full conditions of use

Average price heatmap:
The heatmap of property prices shows current estimated values of specific properties. I've shaded their plot areas by an estimate of current value using a rudimentary automated valuation model. At the higher zoom levels, I've clustered the plot outlines and these aggregated groups are coloured according to their median property values. This map layer is not adjusted for property size, so larger properties will typically be more expensive. This map answers the question as to how much it costs to buy an average property in a given area.
Price per SQM heatmap:
The methodology for this layer is the same, except I use price per square meter instead of current value. Basically I adjust the price depending on how large the property is so smaller properties aren't penalised. This map answers the question as to where the most expensive areas are on a £ per square meter basis.

Annual growth is the compound annual growth rate. You can think of it as the annual growth rate needed to grow the initial purchase price to the eventual selling price. More technically, it is the rate of return that would be required for an investment to grow from its beginning balance to its ending balance, assuming it had grown at a steady rate on an annually compounded basis.

Here is the formula used to calculate this:

CAGR = (Final price / Starting price) ^ (1/time in years) - 1

After inflation is the annual growth rate after adjusting for inflation. I use the official CPIH measure for inflation, this is published as a monthly time-series, so I am able to take the period that corresponds exactly to the purchase and sale in question. I use this to calculate the CAGR for the inflation based on the above cagr formula. I can then use this to get the real growth rate, i.e. annual growth rate adjusting for inflation. The formula is:

Inflation adjusted rate = (1 + Nominal CAGR) / (1 + Inflation CAGR) - 1

Bear in mind that neither of these consider the value of living in the property or the upkeep costs for the period in question.