Property Valuation by ChatGPT: Limits and the Agent's Role
A homeowner who asks ChatGPT, Gemini, Google's AI Mode or Perplexity "how much is my house worth?" gets an answer built from web pages and from what the model has learned, without anyone seeing the property, and the publishers themselves warn that it can be wrong. The estate agent who wants to be found and useful at that moment publishes what an AI cannot check: its valuation method, sourced and dated sold prices for its areas, a short form and a fast reply.
Sources: the AI publishers, HM Land Registry, RICS, The Property Ombudsman and the ICO, read on 6 November 2026. Legal points are our reading, not legal advice.
Do sellers really ask an AI?
We found no UK study, published with its sample, measuring how many sellers ask an AI to value their home. Two surveys give context:
- Ofcom, 2 April 2026: "More than half (54%) of UK adults now use AI tools, such as ChatGPT, Copilot or Gemini" (7,533 adults aged 16 and over, surveyed from 29 September to 28 November 2025).
- Realtor.com, 9 October 2025: 82% of 1,000 US adults buying or selling a home (or who did so within two years) use "AI for real estate insights", yet rate agents "the most accurate source of market information, ahead of AI".
Neither measures valuations as such, but AI is now one of the places where people read about the housing market.
What the AIs answer, according to their publishers
ChatGPT
According to OpenAI's help page on search, "ChatGPT may search the web automatically when your question would benefit from current information", and answers "may include citations". But: "Search results and citations can be incomplete, outdated, or incorrect."
The page "Does ChatGPT tell the truth?" adds that it "can produce incorrect or misleading outputs" and that "The model may express high confidence even in incorrect answers." OpenAI's advice: "Use ChatGPT as a first draft, not a final source."
Google: AI Overviews, AI Mode and Gemini
Google announced AI Overviews for the United Kingdom on 15 August 2024, and AI Mode started to roll out in the UK on 28 July 2025. Both may answer by "issuing multiple related searches across subtopics and data sources", says Google's documentation. Google Search Help warns: "AI responses may include mistakes."
Gemini Apps Help adds: "Not all responses include related links or sources."
Perplexity
Perplexity calls itself an answer engine "searching the web, identifying trusted sources, and synthesizing information", and adds: "we encourage you to double-check sources". Its help centre states: "Each answer includes numbered citations linking to the original sources".
These tools assemble what is published and readable. If the agency's site says nothing about its prices or method, the answer comes from other pages.
Sold prices in public data, and what they leave out
HM Land Registry Price Paid Data
For England and Wales, the reference is HM Land Registry's Price Paid Data: the "Sale price stated on the transfer deed", the completion date, the address and postcode, the property type (detached, semi-detached, terraced, flat or maisonette, other), new build or not, and the tenure. There is no floor area, no number of bedrooms and no condition in that list.
It is updated "on the 20th working day of each month"; the download page added the September 2026 release on 28 October 2026. Its limits, in HM Land Registry's words:
- Registration "typically ranges between 2 weeks and 2 months", so "Data for the two most recent months is therefore incomplete".
- Excluded: "sales that were not for value", "'Right to buy' sales at a discount", transfers "by way of a gift".
- Category B mixes repossessions, some buy-to-lets and transfers to non-private individuals: keep category A for a residential median.
The free Standard Reports give "aggregated prices by geographical area", down to postcode sectors.
The UK House Price Index
The UK House Price Index "includes all residential properties purchased for market value in the UK", down to local authorities, but recent months "can be revised". The September 2026 figures are due on 18 November 2026.
A refitted kitchen, a damp cellar, a bedroom over a busy road: none of this is in Price Paid Data. The seller can tell an AI, but nobody has checked it. That is the valuation visit's job.
Market appraisal, valuation, survey: three different things
In England, Wales and Northern Ireland, The Property Ombudsman's Code of Practice for Residential Estate Agents is "mandatory for all Property Ombudsman (TPO) Members" doing estate agency work there. Its "Market Appraisal" section states: "Any figure you advise, either as a recommended asking price or as a possible selling price must be given in good faith and must reflect available information about the property and current market conditions and must be supported by comparable evidence." The comparables "must be retained on file for future reference".
A formal valuation is different. The RICS Red Book Global Standards, effective from 31 January 2025, apply to RICS members who provide a written valuation. Agency work is an exception: the detailed valuation standards (VPS 1 to 6) are not mandatory when "Providing an agency or brokerage service in respect of the acquisition or disposal of one or more assets". Members who do other valuations must join the Valuer Registration Scheme and may use "the RICS Registered Valuer designation".
The Red Book is explicit about automated tools: "An AVM output that has not been subject to the application of professional judgement by a valuer is also not compliant with these standards." The same rule covers "a model and/or process assisted or produced by artificial intelligence (AI)".
Then valuation vs survey: a survey describes the building, a valuation gives a figure. The RICS consumer guide explains that a Level 2 Home Survey "can be a survey only, or a survey and a valuation", and that "Where the service includes a valuation, the surveyor should also be an RICS Registered Valuer." The lender's valuation is "a limited check on the property" and "is for the benefit of the lender, not the home buyer/owner".
| Type of estimate | Who produces it | Is the property seen? | What the texts say |
|---|---|---|---|
| Answer from ChatGPT, Gemini, AI Mode or Perplexity | An AI model | No | "can produce incorrect or misleading outputs", says OpenAI |
| Standard Report or Price Paid search | The seller, with HM Land Registry data | No | The two most recent months are "incomplete" |
| Instant online valuation (AVM) | An algorithm | No | Without a valuer's judgement, not compliant with the Red Book |
| Estate agent's market appraisal | An estate agent | Yes, if the agent visits | TPO: a figure "supported by comparable evidence" |
| Red Book valuation | An RICS Registered Valuer | Inspection "to the extent necessary" for its purpose | Written valuation under RICS standards |
| RICS Home Survey | An RICS member | Yes: condition "on the date of the inspection" | A valuation only in Level 2 "survey and a valuation" |
Being visible and useful when the seller asks
1. A valuation page that explains your method
Not a "free instant valuation" button: a page that says how the agency values a home, with the comparables you use (Price Paid Data, your own sales), what you check at the visit, the time frame and the written appraisal. Google's guide to generative AI features points the same way: "a first-hand review provides a unique perspective based on personal experience".
The page must be readable by crawlers: for Google, "indexed and eligible to be shown in Google Search with a snippet"; for ChatGPT, OpenAI asks you to "allow OAI-Searchbot to crawl the site". Our article on getting recommended by ChatGPT covers these settings.
2. Prices for your areas, sourced and dated
A citable sentence gives the area, period, property type, number of sales, source and release. A template to fill in: "Median price paid for terraced houses in Chorlton, Manchester, July 2025 to June 2026: £[amount], from [number] sales (our calculation from HM Land Registry Price Paid Data, September 2026 release)."
Add the attribution HM Land Registry requires: "Contains HM Land Registry data © Crown copyright and database right 2021. This data is licensed under the Open Government Licence v3.0." The address data is licensed separately; our reading: publish medians and counts, not lists of addresses. Our guide to neighbourhood pages shows how.
3. Say what your appraisal is
Write it on the page: your market appraisal is an estate agent's opinion of the asking price and likely selling price, backed by comparables. It is not a Red Book valuation and not a survey. For a formal written valuation, refer the seller to an RICS Registered Valuer.
4. A form that asks only for what is needed
Under UK GDPR, Article 5(1)(c), personal data must be "adequate, relevant and limited to what is necessary in relation to the purposes for which they are processed". To call a seller back: postcode or address, property type, number of bedrooms, name, phone or email, preferred time. Link your privacy notice.
For the phone, the ICO explains that "Live marketing calls are solicited if someone specifically asks you to call them with marketing information", and then "most of the PECR rules don't apply (eg you don't need to check the number against the TPS)". Calling back about the requested valuation fits that case, in our reading. A call about a mortgage or a lettings offer is unsolicited: allowed to numbers "that aren't on the TPS or CTPS", if there is "no previous objection to your calls". On consent, the ICO quotes the UK GDPR: "Silence, pre-ticked boxes or inactivity should not therefore constitute consent." The live calls guidance "is under review" after the Data (Use and Access) Act.
5. Google Business Profile and reviews
According to Google's guide, "Google Business Profiles can help your products and services to be visible in both AI responses and other Google Search results". And on local ranking: "More reviews and positive ratings can help your business's local ranking."
6. Reply quickly
Call back the same day if you can, offer a visit, and explain the gap between the AI's figure and your comparables. If a seller asks you to stop, the TPO Code is plain: "You must act promptly if a consumer asks you to stop canvassing them."
Steps to take this month
- Ask the AIs about a typical home in your area, and note the sources they cite.
- Write the valuation page: method, visit, timing, written appraisal.
- Add the sentence "Our market appraisal is not an RICS Red Book valuation or a survey."
- Publish the median per area, with sales count, period, Price Paid release and attribution.
- Cut the form to useful fields, with privacy information and an unticked box for other marketing.
- Check indexing (URL Inspection tool in Search Console) and that robots.txt blocks neither OAI-SearchBot nor PerplexityBot.
- Update your Google Business Profile and ask for a review after each sale.
- Set a callback time in the team, keep it, and keep your comparables on file.
An agency example
Chorlton Lane Estates, a fictional agency in south Manchester, meets sellers who arrive with a figure from an AI. Its "free instant valuation" form had fourteen fields.
In a month, it publishes a "How we value your home" page signed by its sales manager: comparables, points checked at the visit, contents of the written appraisal, which is not a Red Book valuation. The page gives the median price paid in Chorlton, Didsbury and Levenshulme by property type, with sales counts and release date. The form drops to six fields, and every request gets a call the same day. No AI is bound to cite this page, but it says what no other page can say for the agency.
What Cleemo offers
A valuation page only helps if requests are followed up. With Cleemo, each agency has its own AI assistant, isolated from the others: it "finds information in your files, reads your documents, prepares a listing or a draft reply, then waits for your approval". Cleemo App (sales, property management, CRM) works without AI; Cleemo AI adds the assistant to it, or works around your current software, depending on its access. Nothing goes out without your approval, and the assistant's actions are logged. See our AI employees.
Frequently asked questions
Can ChatGPT value my house?
It can give a figure, built from web pages or from what the model has learned, without seeing the property. OpenAI warns that it "can produce incorrect or misleading outputs". It is neither an estate agent's market appraisal nor a valuation.
What is the difference between a market appraisal and a valuation?
A market appraisal is the estate agent's advice on the asking price and likely selling price, which the TPO Code says must be "supported by comparable evidence". A Red Book valuation is a written valuation under RICS standards, and RICS members who do this work must join its Valuer Registration Scheme.
Valuation vs survey: which one does a buyer need?
A survey describes the construction and condition of the property; a valuation gives a figure. The lender's valuation is only "a limited check on the property" for the lender's benefit, so RICS advises buyers to get a Home Survey. Its Level 2 can include a market valuation.
Why doesn't Price Paid Data cover Scotland?
Price Paid Data covers England and Wales only. Scottish sales go to Registers of Scotland, and the UK House Price Index adds them to the UK figures. In Scotland, the seller must also arrange a Home Report, with a Level 2 survey and valuation, before marketing the home.
How can an estate agent appear when a seller asks an AI for a valuation?
Nothing guarantees it: for ChatGPT search, OpenAI writes that "Placement is not guaranteed." An indexed valuation page, sourced and dated prices, a current Google Business Profile and reviews give the AIs the agency's own material.
Can an estate agent call back a seller who asked for a valuation online?
Yes, about that request: for the ICO, a call is solicited when someone "specifically asks you to call them", and most PECR rules then do not apply. For other offers, check the TPS and any objection first. This is our reading, not legal advice.
Is a CMA the same as an appraisal in the US?
No. An appraisal follows USPAP, the standards of The Appraisal Foundation, and "States license appraisers and enforce those standards." Under the NAR Code of Ethics, a REALTOR® giving a price opinion outside a listing or a purchase offer must state when it "is not an appraisal".
