How we score home health

A Proven Report puts a 0–100 health score on a home and on each of its parts. That number is only worth something if you can see how it was produced and where the underlying expectations come from. This page is the full methodology — no black box.

Two kinds of items, scored two different ways

Not everything in a house wears out the same way, so we don't score it the same way.

• Age-governed items run on a replacement clock. A roof shingle, an air conditioner, a water heater, carpet, sealants, an electronic lock, an appliance — these have a well-defined service life and reach the end of it whether or not they look good. For these, the score is the worse of two signals: how much rated life is left, and the observed condition. An old water heater is a real risk even when it photographs clean, so age can pull the score down on its own.

• Condition-governed items last the life of the house with reasonable care. Hardwood floors, tile, natural stone, masonry, drywall, solid cabinetry — the published life-expectancy charts rate these "Lifetime / 100+." For these, condition is the whole score, and age never caps it. A cared-for 40-year-old hardwood floor that photographs beautifully reads high; its age is shown only as neutral context ("installed ~40 yrs ago"), never as a penalty.

Which bucket an item falls in is a researched property of its material, taken from the sources below — not a guess. It is also independent of where the item appears on the report: a roof is shown under Structure & Finishes but is still scored on its age clock.

The condition rubric

When condition matters, the grade is a visual assessment of the surface, mapped to a consistent band:

• Pristine / like-new — flawless, recent
• Good — no problems found — clean and intact, no visible defects (a clean assessment is a real high grade, not a guess)
• Dated but sound — out of style yet undamaged
• Worn — visible wear, scuffs, fading
• Damaged — cracks, water stains, peeling, gouges

The grade is inherently subjective; the rubric is what keeps it consistent and explainable.

Why some items show "—"

If we have never actually assessed an item — no photo grade, and for an age-governed item no usable installation date — it shows "— · No data available." It contributes nothing to the category or the home score. We never assume an un-assessed item is healthy, and we never count it as 100.

This is deliberate honesty. A home that has just started its record will show a modest score that reflects only what has truly been measured. The number climbs as real photos, dates, and service records arrive — it is earned, not granted.

Where the life-expectancy figures come from

Our service-life expectations are based on published, industry-standard home-component life data. The exact per-item mapping and weighting are ours, but the sources are public and named:

• InterNACHI — Standard Estimated Life Expectancy Chart for Homes — the primary component-by-component chart, including the "Lifetime / 100+" ratings that decide age-governed vs condition-governed.
• InterNACHI — Life Expectancy Chart for Florida Homes — the hot/coastal-climate variant (relevant to Phoenix; a climate de-rating is a planned refinement).
• NAHB / Bank of America Home Equity — Study of Life Expectancy of Home Components (Feb 2007): reproduced figures and the original report PDF.
• Carson Dunlop — Home Improvement Life Cycles & Costs and their HVAC/AC maintenance guide — corroboration for HVAC and ductwork life.
• Quartz / engineered-stone countertops: howtolookatahouse.com and Angi — durable engineered stone (~30+ years), so we treat it as condition-governed.
• Smart locks / electronic deadbolts: The Connected Shop — smart door lock lifespan — a device life of ~5–7 years driven by its electronics, so we treat it as age-governed (a plain mechanical deadbolt stays condition-governed).

The bottom line

Age-governed items are scored against industry service-life data; condition-governed items against observed condition; un-assessed items are shown honestly as "—" and excluded. The methodology is open and the sources are cited; the exact mapping and weights are ours. The score can only go up as a home's record fills in — which is exactly what makes it trustworthy.