21 Cwm Gwynlais, Tongwynlais, Cardiff, CF15 7HU

UPRN:100100137017Detached House3 bedsBuilt 1976-1982

FreeholdCouncil Tax: Band FEPC: C (72)

Data freshness:Listing· freshPlanning· 4mo agoEPC· 6mo agoRisk· 2y agoConnectivity· 1mo agoSchools· 1mo agoAmenities· 2mo agoArea· Census 2021Council Tax· 4mo ago

21 Cwm Gwynlais, Tongwynlais, Cardiff, CF15 7HU

HP Score

/ 100

Mixed

Verdict

5 days ago

Verdict: INVESTIGATE, on a scale of Buy, Investigate, Avoid.
Mixed signals - investigate

Evidence

16 of 21 sources

Sale Estimate

£403,000

£383k - £423kHigh

Estimate

£403k

Range

£383k – £423k

Rent Estimate (pcm)

£1,350

£1k - £2k

Monthly

£1,350

Yield

4.44%

Verdict

Derived from HomePortfolio scores

21 Cwm Gwynlais earns an INVESTIGATE rating with HP Score 72/100. Investment score 67/100 reflects moderate fundamentals. Crime intensity is moderate. Flood risk is not assessed: check the Environment Agency long-term flood map before offering. Tenure is freehold. Every figure here comes from the live HomePortfolio API; anything it does not publish is left out.

Key SourcesEPC RegisterPortal listingsOfcom Connected NationsOfcom mobile coverageMarket estimates (third-party AVM)HM Land Registry sales matched to addressONS Census 2021Police.ukHM Land Registry covenantsHM Land Registry Price PaidPlanIt / council planning portalsOverture Maps PlacesOfsted / DfE GIAS

HP Score

72/ 100

Mixed

Investment Score

67/ 100

Moderate

Crime Score

38/ 100

Elevated

Walkability

No data

Transit & Bike

No data

Opportunity

Why this could be an opportunity

Low confidence0 independent sourcesListing checked 3 Nov 2026

This rests largely on a single source. Treat the score as a prompt to investigate, not a conclusion.

Valuation edge0/15
claims [AVM +9.4% (HIGH)] → measured edge +0.00pp of the ask; on later-registered sales an AVM discount carried no edge and a sold-evidence gap at most +0.5pp
Market estimate used (HIGH confidence) · snapshot 12 Oct 2026
- valuation_snapshotsestimate for 100100137017· as of 12 Oct 2026
Rental economics0/40
gross yield 4.4%; range width penalty ×0.76
- valuation_snapshotsrent estimate 1350/mo (range 1200-1500)· as of 12 Oct 2026· verify before relying on this
Stress margin0/30
stressed cash flow -678/mo, -50% of rent (6.75% on a 75% loan; no service charge or ground rent disclosed); fails the stress - earns nothing
- underwriting_assumptionscosts not disclosed by the advert· as of 3 Nov 2026
Seller motivationNot scored
context, not scored: 1 price cut(s), 78 days on market; homes with a cut sold 0.2-0.3pp further below the cut ask, which is not an edge
- portal_listingsprice_changes + first_published_date· as of 3 Nov 2026
Risk & liquidity14.7/15
187 sales/12mo in area; valuation range width 10%
- property_intelligencetransactions_12mo

4 of 4 components scored. Ranks on gross yield, the stress margin, risk and disclosed facts. A pricing claim earns only its measured edge: today 0 for the market estimate and at most +0.5pp for sold evidence. The score itself is not yet checked against the outcomes of homes it scored.

Economics

What happens to your money

Price sensitivity

£274,000£419,500

The same scorer re-run at hypothetical asking prices, holding rent, comps and listing history constant. Not a prediction of what the seller would accept.

Your assumptions

Purchase price£365,000

At the asking price

Monthly rent£1,350/mo

Evidenced range £1,200-£1,500

Interest rate5.4%

Loan to value75%

Cash required: £119,050
Net cash flow: -£297/mo
Cash on cash: -3.0%
Score at this price: 15

After a 8% void allowance, 15% management and 10% maintenance. Lender coverage (rent ÷ interest): 1.10 - below the usual 1.25 test. These are your assumptions, not evidence: only the pre-filled rent and price come from the record.

Evidence

Where every number comes from

valuation_snapshotsestimate for 100100137017Valuation edge · as of 12 Oct 2026
valuation_snapshotsrent estimate 1350/mo (range 1200-1500)Rental economics · as of 12 Oct 2026 · verify before relying on this
underwriting_assumptionscosts not disclosed by the advertStress margin · as of 3 Nov 2026
portal_listingsprice_changes + first_published_dateSeller motivation · as of 3 Nov 2026
property_intelligencetransactions_12moRisk & liquidity

Sold comparables in depth

Risks

What could kill this deal

Score confidence is low
largely a single source - treat the number as a prompt, not a conclusion
Rental economics needs verification before you rely on it
rent estimate 1350/mo (range 1200-1500)
Seller motivation could not be scored
context, not scored: 1 price cut(s), 78 days on market; homes with a cut sold 0.2-0.3pp further below the cut ask, which is not an edge

Property risk deep-dive →

Plan

Before you offer

1. Get two written rental appraisals from local lettings agents.
The rent estimate rests on area-level evidence, not lettings on this street.
2. Ask the agent why the price was reduced and whether a previous sale fell through.
1 price cut(s) recorded on the listing history.
3. Treat the gap to the estimate as unproven - compare recent sold prices on the street yourself before pricing an offer around it.
On later completions, homes listed below their estimate sold at the same share of the asking price as the rest.
4. Commission a full structural survey, not a basic condition report.
The score prices market evidence, not the fabric of the building.

Valuation & Market

Sale Estimate£403,000

Rent Estimate (pcm)£1,350

Gross Yield4.44%

1y Growth-

3y Growth+5.5%

5y Growth+3.8%

10y Growth+4.9%

Last Sold Price£102,000 (2000-05-23)

View Market Details

Risk Overview

Flood RiskUnknown
SubsidenceLow
RadonModerate
MiningSignificant
LandslideModerate
Air QualityLow
NoiseWithheld

View Full Risk Report

Planning Activity

Recent Apps

0CF15 7HU

Approval Rate

-12mo

Development

low

26/02209/HSE
Rebuild of existing, defective retaining wall, to include new steps and bin store
Pending
26/01761/FUL
Proposed subdivision of existing dwelling to create two self-contained dwellings; with associated internal reconfiguration, garage extension and alterations
Pending
26/01650/HSE
Single storey extension to rear.
Pending

View Planning Timeline