Empty homes in Spain: how many there really are, and where

Every housing debate in Spain reaches the same point sooner or later: with millions of empty homes, why build more? The figure is real. It comes from the INE's 2021 census, published on 30 June 2023, which counted 3,837,328 empty homes on 1 January 2021, 14.4% of the 26,623,708 dwellings in the country. Housing Europe's 2025 report on Spain repeats it, noting that vacant homes make up almost 15% of the stock and more than 25% once seasonal and holiday homes are added.

What the number means, and where those homes are, is a more useful story than the headline.

How the census counts an empty home

The 2021 census was the first to classify homes using electricity data. Until 2011 a census agent visited each building and recorded whether a home was a main residence, a second home or empty. In 2021 the INE used the annual declarations of electricity consumption that supply companies file with the tax authorities, matching about 28.8 million meters to homes.

Its definition is precise. A home counts as empty if it has no electricity contract, or if its total consumption over the previous year was lower than an average home in the same municipality would use if it were occupied for 15 days. The threshold changes from place to place because consumption varies a great deal by climate. On top of that, the INE set a fixed band: homes using between 251 and 750 kWh a year, roughly one to three months of use, are classed as sporadic. There are 2,514,511 of them. A further 943,924 homes fall between the empty threshold and 250 kWh.

Two cautions follow. The INE itself labels these results provisional and says the sources still need work. And an empty home by electricity is a home with almost no use over a year, whatever the reason: a flat awaiting an inheritance, a house in a village whose owners moved to the city decades ago, a home being renovated, a unit nobody wants to buy.

Where the empty homes are

The geography settles most of the debate. Municipalities of under 10,000 inhabitants, where 20.3% of the population lives, contain 45% of Spain's empty homes. In municipalities of fewer than 1,000 people, a third of all homes are empty, 38.3 for every 100 residents. Cities of more than 250,000, home to 23.8% of the population, have only 10.5% of the empty homes, 3.6 for every 100 residents.

Among the 30 cities with over 200,000 inhabitants, the highest rates are in Santa Cruz de Tenerife (17.3%), Vigo (15.1%) and A Coruña (14.7%). Barcelona's rate is 9.3%, Valencia's 8.8%, Seville's 7.5%, Málaga's 6.4% and Madrid's 6.3%. Some commuter towns around Madrid are near the bottom of the national table: Fuenlabrada at 2.9%, Móstoles at 3.1%, Alcorcón at 3.2%. The highest rates among towns over 10,000 people are in places like Tías in Lanzarote (48.0%), Mos in Pontevedra (46.5%) and Monforte de Lemos (40.0%).

Set that next to the shortage. The Banco de España, as elDiario.es reported in June, puts the deficit at 750,000 homes for 2021–2025, with 52.5% of it in six provinces: Madrid, Barcelona, Alicante, Valencia, Murcia and Málaga. The empty homes are largely somewhere else. The same report does see room to mobilise homes in Madrid and Barcelona, between 300,000 and 350,000 if tourist flats, second homes and empty homes are counted together, while warning that bringing them into use is hard. It also cites government data on about 450,000 unsold homes from the boom, many of them in places where few people want to live.

What Spain does about them now

The 2023 housing law gave councils a tool. They can add a surcharge of 50% to the IBI property tax on homes empty for more than two years without good reason, rising to 100% after three years and up to 150% for owners with two or more empty homes in the same municipality. The catch is the definition, which applies only to owners of four or more homes and excludes many cases: homes for sale for up to a year or for rent for up to six months, homes under renovation or in litigation, second homes for up to four years, and owners away for work or health reasons. Each council has to pass its own bylaw to use it.

The Basque Country has tried the other route for years. Under its Bizigune programme, owners hand an empty home to the public rental agency Alokabide on a six-year usufruct. Alokabide lets it to people on the Basque housing register and pays the owner a monthly rent, up to €700 under the latest decree, for the full contract. It manages repairs, insures the home, pays some local charges and returns it in good condition at the end. It even offers an interest-free advance for renovation, repaid from the rent.

A radical-centre approach to empty homes

The OECD's Brick by Brick puts empty homes in the right place: taxing vacant homes encourages greater use of existing housing, alongside renovation and neutral rules for tourist lets. It treats this as one tool among several, next to new building where demand is.

A radical-centre policy combines the two Spanish instruments and aims them carefully. From the left comes the principle that a home kept empty in a city short of housing has a cost for everyone else, and the council should be able to charge for it. That means a surcharge that applies in declared stressed areas to any owner of a long-empty home there, whatever the size of their portfolio, with the current exemptions for sale, renovation and illness kept. From the market-liberal tradition comes the observation that many owners leave flats empty because they fear unpaid rent and slow recovery of their property. A Bizigune-style public lease, with guaranteed rent, insurance and a home returned in good condition, answers that fear directly, and it should be offered in every pressured metropolitan area. It links to the rent-default insurance we proposed in tenants and landlords: ending the war.

The idea that fits neither camp is to count first and aim second. Electricity data now let Spain know, municipality by municipality, where the empty homes are. In Madrid, Barcelona and Málaga they are a modest share of the stock and worth the effort. In thousands of small towns they are a symptom of depopulation and belong to rural policy, with renovation grants and services that bring people back. Empty homes are a useful supplement in the cities that need housing, and the plan to build more is what closes the gap.