Valuing a home from Property Price Register comparables

Valuation by comparison is the method every professional valuer uses and the one any careful buyer can run at a kitchen table. You find recent sales of homes as similar as possible to the one in front of you, you adjust each of them for the ways in which it differs, and you read the middle of what remains. The register gives you the raw material for the first step and almost nothing for the second, which is why the method matters more than the data.

What a comparable actually is

A comparable is a closed sale of a property so like the subject that any remaining difference can be argued about in euro. Similar location, similar type, similar size, similar condition, similar date. Every one of those five that you have to relax weakens the evidence, and relaxing two at once usually destroys it. A three bedroom semi in the same estate that closed four months ago is a comparable. A four bedroom detached house two kilometres away that closed in 2021 is a distraction with a price attached.

The register cannot tell you the type, the size or the condition, so you are matching on address, date and price, then filling in the rest yourself from listings, from the building energy rating certificate and from walking past. That sounds laborious because it is. It is also the difference between a number you can defend to a seller and a number you got from an online estimate.

Building the shortlist

1. Search the register for the estate, road or townland by address text rather than by county, and pull everything for the past twenty four months.
2. Remove every row flagged as not full market price. Those transfers were never priced by a market and will drag your middle downward.
3. Split new dwellings out from second hand ones. If the subject is second hand, work with second hand rows only where you can.
4. Drop anything whose address suggests it is not the same kind of property: a house name with land attached, a commercial address, an obvious site sale.
5. Aim for five to eight survivors. Three is thin, fifteen usually means you have widened the net too far and started comparing different streets.
6. Cross check the shape of the result against the area pattern on our Irish sold price pages before you go any further.

If the estate produces nothing usable, widen by street before you widen by distance, and widen by distance before you widen by time. A neighbouring road last month is almost always better evidence than the same road three years ago, because the property is more comparable than the market is.

Filling in the size the register does not hold

Nothing in the register tells you how big any of these houses are, and a price without a size is a number without a denominator. Two homes on the same road at the same price can be a bargain and a disaster depending on forty square metres. So the floor area has to come from somewhere else, and in Ireland there are three reliable places to look.

• The building energy rating certificate. A BER is required before a home is advertised for sale, and the certificate states the floor area used in the assessment, along with the rating itself.
• The original sales listing or brochure. Agents quote floor area in square metres and often publish a floor plan, and old listings for the comparable properties are frequently still findable.
• Planning records. Where an extension was built with permission, the application drawings give the areas before and after, which also tells you which houses on the road are no longer the size they were built at.

Assemble those and you can finally do the arithmetic that matters: price per square metre for each comparable. That single conversion turns a scattered list into something readable, because it removes the largest source of variation between houses and leaves the differences you actually want to argue about. The reasons the register will never supply it are set out in why the register has no floor areas.

Adjusting for time

A comparable that closed a year ago was priced in a different market, and the date on the row is later than the day the price was agreed. Both facts push in the same direction: older rows need adjusting before they can sit beside a current one. The tool for this is the residential property price index published by the Central Statistics Office, which is the official measure of price change and is produced separately for Dublin and for the rest of the country.

Apply it honestly and lightly. Move each comparable forward by the index change between its month of sale and the present, note beside it that you have done so, and treat the adjusted figure as slightly less reliable than an unadjusted recent sale. An index describes a region, not a road, and the further you stretch it the more of your answer comes from the index rather than from the evidence.

Adjusting for everything else

The discipline that saves you is writing the adjustments down. When the total of your judgements outweighs the spread of the underlying evidence, you have not valued anything, you have decorated a guess. Keep the adjustments small and few, and prefer better comparables to cleverer corrections.

Turning the set into a range

Do not produce a single number. Produce a range with a middle, because that is what the evidence supports. Take the adjusted prices per square metre, discard the highest and the lowest if you cannot explain them, and apply what remains to the floor area of the subject property. The width of the surviving values is the width of your range, and a narrow range from five close comparables is worth far more in a negotiation than a precise figure from two distant ones.

Then sanity check upward. Look at what similar homes are currently asking nearby, remember that asking prices and register prices are different animals for the reasons set out in asking price versus sold price, and ask whether your range sits sensibly against both. If it sits below every live asking price and below every recent closing, you have made an arithmetic error somewhere.

When to stop and pay a valuer

This method is for deciding what to bid, what to ask, or whether an agent guide is fantasy. It is not for anything with legal or tax consequences. A mortgage requires a valuation by a valuer the lender accepts. Probate, capital acquisitions tax, a separation agreement and a company transfer all need a professional valuation that somebody is prepared to stand over. Do the register work anyway, because it makes you a much better client, and then hire the person whose signature is required.

Sources: comparable sales from the Residential Property Price Register, published by the PSRA from stamp duty returns and covering the State since 2010. The price index used for time adjustment is published by the Central Statistics Office. Nothing here constitutes a valuation of any particular property.