Key takeaways: an online estimate calculates an average; a professional valuation establishes your property's value. The difference can be quantified: our market analysis shows an average gap of around 7% between asking price and sale price, i.e. €52,000 on a typical property, largely due to poorly calibrated starting prices. A real valuation crosses actual notarised sales, the property's precise condition, its micro-location and the solvency of local demand, following a recognised valuation method. Here is how it is built, and how to recognise a serious one.
Why online estimators get it wrong
Automatic valuation tools have three structural limits:
- They work on asking prices, not on prices actually signed at the notary. Yet the gap between the two averages 7%: the algorithm learns from sellers' ambitions, not from market reality.
- They cannot see your property: actual condition, quality of renovation, light, views, layout, nuisances, parking. Between two apartments identical on paper, these factors commonly create 10 to 20% of value difference.
- They average the municipality, whereas value is decided street by street: in Pétange as in Differdange, two addresses 500 metres apart can sell at very different prices per m².
An online estimator gives an order of magnitude: useful for dreaming, dangerous for deciding. Setting your sale price on it means flipping a coin for €50,000.
What a professional valuation really analyses
| Dimension | What is examined |
|---|---|
| Property characteristics | Exact floor areas, layout, floor, orientation, parking, outdoor spaces, energy class |
| Condition and renovations | Works carried out (with invoices), quantified works to plan, actual wear |
| Surroundings | Micro-location, amenities, schools, transport, urban projects, nuisances |
| Market | Comparable notarised sales, competing supply online, observed selling times, solvency of local demand |
| Legal and technical | Co-ownership (charges, voted works), easements, any tenancy in place |
At CARMO, this analysis follows the European TEGoVA valuation standards, with a systematic visit of the property: no serious value is established from a desk.
The professionals' three methods
- Comparison: the leading method for residential. The property is set against actually concluded sales of comparable properties, adjusted for differences (condition, size, location).
- Yield: for investment properties, value derives from the market rent and the return investors expect in the area.
- Replacement cost: what the same property would cost to build today, land included, minus wear. With construction costs sharply up, this method objectively supports the value of existing properties.
A solid valuation crosses at least two methods and results in an argued range, not a number out of a hat.
The right price is a strategy, not a number
A valuation is not there to flatter the seller: it is there to sell at the best real price. The first weeks of marketing concentrate most active buyers; an overpriced property lets them pass, goes stale online, then gets negotiated harder. The mechanism is documented in this CARMO blog article: asking price vs sale price, the gap sellers underestimate. Professional best practice is to define from the start a launch price and a staged repositioning strategy, steered by real market feedback, rather than suffering improvised cuts.
To position your area, the references by municipality are in this CARMO blog article: price per m² in southern Luxembourg, municipality by municipality.
Agency valuation, bank appraisal: do not confuse them
Your buyer's bank will have the property appraised by its own expert to validate the financing: that is a collateral appraisal, often conservative. The marketing valuation targets the market price achievable with real buyers. A correctly valued property sails through the bank appraisal; an oversold one risks seeing the buyer's financing refused, and the sale collapse at the worst moment. Valuing correctly therefore also protects the solidity of your transaction.
If you are selling, if you are buying
If you are selling
Demand an argued valuation: comparables cited, condition factored in, a price strategy proposed. Beware of the highest estimate "to win the mandate": it is the leading cause of sales that drag. The right reflex: ask how the number was built.
If you are buying
A counter-valuation before making an offer keeps you from overpaying and arms your negotiation: a documented gap between asking price and estimated value is the best discussion argument there is, especially on a property listed for several months.
When should you have your property valued?
A sale is not the only occasion. A serious valuation is also essential in an inheritance, to divide fairly between heirs (see also this CARMO blog article: selling an inherited property in Luxembourg), in a separation, to buy out the other's share at the right price (see also: separation or divorce, what happens to your property), before major works, to choose between renovating and selling, or simply to know your wealth before a financial decision. In all these cases, a badly established value is paid for in conflicts or taxes: better to start from a solid figure.
Frequently asked questions
How much does a property valuation cost in Luxembourg?
A valuation carried out by an agency with a view to a sale is generally free and without obligation. A certified appraisal for bank, tax or judicial use is a separate paid service.
How reliable are online estimators?
They give an order of magnitude from averages and asking prices, without seeing the property. The gap with real value commonly reaches 10 to 20% depending on condition and micro-location: enough to get an idea, not enough to set a price.
Which documents should you prepare for a valuation?
Purchase deed, plans and floor areas, energy performance certificate, renovation invoices and, in a co-ownership, the charge statements and general meeting minutes. The more complete the file, the more precise the valuation.
Does a valuation commit me to selling with the agency?
No. The valuation is a diagnosis of value; the decision to sell, the timing and the support remain your choice.
Why do two agencies give different valuations?
Because the method and the intention differ: comparables selected, condition factored in, and sometimes a wish to flatter in order to sign a mandate. Compare the reasoning, not the numbers: the best valuation is the one that justifies itself line by line.
What to remember: your property is worth neither an algorithm's number nor the most flattering estimate: it is worth what a solvent, properly informed buyer will sign for at the notary. That is exactly what a professional valuation measures, with notarised figures and a visit to back it up. Ours is free, argued, and you leave with a price strategy, not just an amount.
Request my free valuationRead: asking price vs sale price
Sources and references
- Housing Observatory: registered sale prices (notarial deeds) and advertised rents
- STATEC: residential property price indices
- TEGoVA: European Valuation Standards (EVS)
- CARMO Immobilier analyses: asking/sale price gap and observed selling times in the southern region
By David Carmo, founder of CARMO Immobilier, has been a real estate professional since 2008. A former member of the board of directors and disciplinary council of the Chambre Immobilière du Grand-Duché de Luxembourg, he is today a founding member and board member of the Fédération des Agents Immobiliers (FAI) and a trainer at the Académie de l'Immobilier.
This article is for information purposes. Any value stated online or in writing without visiting the property remains indicative.