1In short
An online valuation (or AVM, Automated Valuation Model) estimates a property's value using a statistical model fed by public and market data, in seconds and without an on-site visit. Terraes does this transparently: it shows the range, the confidence level and the sources, instead of returning a single number behind a form.
2The sources
Each estimate combines, depending on availability by area:
- Cadastre (IGAC): the cadastral value per m² and its annual valuations, which serve as a historical anchor and official reference.
- Estrato (DANE): socioeconomic context that helps frame the area.
- Market listings: active listings on real-estate portals, which reflect what sellers are asking today.
- Registered sales (SNR): where available, real transactions recorded at the Superintendency of Notaries and Registry, which validate the price actually paid.
AMVA property observatory and environmental noise
In the Aburrá Valley, OIMET provides published offers and appraisals. We filter for residential use, remove duplicates and explicitly rejected or pending surveys, and give recent visits more weight with a three-year half-life. Published records with no survey state remain identified as such. Adjusted values per m² take priority; the original field is the fallback.
The nearby OIMET reference includes its sample, search radius and visit dates, and contributes zero weight to the central estimate. In residential segments with a validated correction for the current model and full public estimate pipeline, OIMET also calibrates the estimate. The current evaluation covers limited, incomplete descriptions without bedrooms, bathrooms, socioeconomic stratum or construction year. The correction applies only within that scope. Estimates containing those facts or attributes resolved from geographic sources retain their existing calculation until an equivalent evaluation is available. The correction is fitted on earlier observations, its strength is selected on middle dates, and its effect is evaluated on a separate later sample. An applied result shows the value before and after the adjustment, its strength, evaluation date and observation dates.
Correction strength describes how much of the fitted adjustment is applied; it is not the percentage of the price supplied by OIMET. The central price and its ranges are scaled together, preserving their relative width. Evaluation reports agreement with published offers and appraisals, not accuracy against completed sales. Each result also discloses whether overlap with the base model’s historical training data is known.
Metropolitan land-value zones serve as geographic references, preserving the type of cadastral value. They are not property-level sale prices or training labels. Environmental noise contours were modeled in September 2022 at a height of four metres. They describe historical exposure bands, not a current reading or an indoor measurement. Airport, metro and industry layers have coarse coverage and only support presence flags.
OIMET · AMVA · Metropolitan land values · Noise sources and limits
How to read AMVA property data · How to compare noise before choosing a home
3Why a range, not a number
We report the median (the central value: half are worth less and half more) and a range around it. The p25–p75 range contains the middle half of properties, and the wide p10–p90 range runs from the cheapest 10% to the most expensive 10%. Condition, floor, view and renovations can change the value of two properties on the same block.
4Is an online valuation reliable?
It depends on what for. As a guide, yes: it gives you a fast, comparable and transparent reference for the value of an area or a property, ideal for making a first informed decision, negotiating with context or understanding the market. As a legal document, no: an online valuation does not replace a certified commercial appraisal.
For it to be reliable as a guide, what matters is that it's transparent about its uncertainty. That's why Terraes shows the range and the confidence level by city, and doesn't pretend to a precision the data doesn't support.
5Limitations
Terraes estimates are indicative and informational. They do not constitute a commercial appraisal under Decreto 1420 de 1998 or IGAC regulations, are not performed by an appraiser registered in the Open Registry of Appraisers (RAA, Ley 1673 de 2013), and should not be used as the sole basis for purchase, sale, credit, collateral, taxation or litigation decisions. For a valuation with legal effect, consult an appraiser or competent authority.
Where coverage is limited, we say so openly on the corresponding city page. We prefer to admit the uncertainty rather than invent a precise figure.
6Frequently asked questions
¿Cómo se calcula el avalúo de una vivienda en línea?
Se cruzan datos públicos y de mercado: el avalúo catastral (IGAC), el estrato (DANE), los avisos en oferta de los portales inmobiliarios y, donde existen, las ventas registradas (SNR). Con eso un modelo automatizado (AVM) estima el precio del m² de cada zona y predio, y lo reporta como una mediana con un rango p10–p90.
¿Es confiable un avalúo en línea?
Es confiable como orientación: te da una referencia rápida y transparente del valor, con su rango y sus fuentes. No es confiable como documento legal: no reemplaza un avalúo certificado por un perito inscrito en el RAA (Ley 1673 de 2013). Por eso Terraes muestra el rango y el nivel de confianza, en vez de un número único que aparente más precisión de la que existe.
¿Por qué reportan una mediana y no un promedio?
La mediana es el valor central: la mitad de los inmuebles vale menos y la mitad más. Es robusta frente a precios atípicos (un inmueble muy caro o muy barato no la distorsiona), mientras que el promedio sí se desvía. Por eso es más representativa del mercado real.
¿Cada cuánto se actualizan los datos?
Recalculamos las estimaciones a diario con los avisos vigentes y guardamos un registro mensual para mostrar cómo evoluciona el valor con el tiempo. El avalúo catastral (IGAC) se actualiza por vigencia anual.
¿Qué pasa cuando hay pocos datos en una zona?
Lo decimos. Si una ciudad o un barrio tiene señal limitada, lo marcamos como referencia catastral o cobertura limitada en vez de inventar una cifra precisa. La honestidad sobre la incertidumbre es parte de la metodología.
Want to see the difference from the cadastral value? Read our guide on cadastral vs. commercial appraisal or explore the valuation by city.