# Methodology

> How Garage Door Lab researches equipment, prices and water problems, including sourcing, cost models and limits.

Canonical: https://garagedoorlabs.com/methodology/

Last updated: 2026-11-08

Every number on this site is either sourced or labelled as an estimate. This
    page explains the difference, and how a claim gets from a spec sheet to a
    published page.

## 1. Primary sources first

    For equipment we work from the manufacturer's spec sheet and the NSF/ANSI
    certification listing for the specific model — 42 for taste and odour, 44 for
    softeners, 53 for health contaminants, 58 for reverse osmosis. For prices we
    use published retail and installed-price ranges, and for water problems we
    use state health department and EPA guidance on private wells.

## 2. Cost models show their inputs

    Installed cost is modelled from visible inputs: equipment price, installation
    scope (drain, electrical, permit, bypass), consumables per year, and a
    five-year service reserve. We do not present a single "average cost" as if it
    were a quote; the range and what it includes are stated on the page.

## 3. Product selection

    We compare certified removal, capacity against household use, five-year cost
    per gallon, parts availability and warranty. A product earns a recommendation
    when it meets the stated criteria; it cannot buy a place in a ranking. Every
    affiliate relationship is disclosed on the page and in the footer.

## 4. What we have not tested

    We do not run a laboratory and we do not install every system we write about.
    When a claim comes from a manufacturer spec, a certification listing or an
    installer report, we say which. We do not imply first-hand testing we did not
    perform.

## 5. Sources we work from

     |
       | Source type | What it decides | How it is cited

       | NSF/ANSI listings | Which contaminants a unit is certified to remove | Standard number and model named

       | Manufacturer spec sheets | Grain capacity, flow rate, membrane output | Spec reproduced with the model

       | Municipal water quality reports | Baseline hardness, chlorine, nitrate | Supplier and year named

       | State well guidance | Testing intervals and contaminant limits | State agency named

       | Published parts and salt pricing | Running cost per year | Price band with the month checked

    When two sources disagree, the page says which one it followed and why. A
    figure that cannot be traced to a document is labelled an estimate, and an
    estimate is never presented as the price of a specific install.

## 6. Corrections

    If a certification changes or a reader finds an error, we update the article
    and its "last updated" date. Email
    [contact@garagedoorlabs.com](mailto:contact@garagedoorlabs.com)
    with the page and the correction.

## 7. How directory listings are verified

    The service-areas directory starts from public business records: the firm's own
    website, its published address and phone number, and the state or city licence
    register named on its city page. A record is marked **verified** only
    when a person has checked the name, street address, phone number and licence
    against those sources and recorded the date. The date is shown on the page as
    “Information last verified”.

    A licence lookup proves that a registration exists and is current on the day it is
    checked. It does not prove the quality of the work, the firm's current insurance
    cover, or that the firm will honour a warranty. Those are questions for the firm
    and, where relevant, the insurer. The directory does not sell placement and does
    not accept payment for a higher position.

    Public ratings and review counts are shown only when the source is licensed and
    attributed. The directory does not write review text, invent a rating, or present
    an estimate as a quote. Cost bands are planning ranges: the national band is dated,
    and the metro factor is labelled as an editorial estimate.

    Records marked **sample** are synthetic template data. They are
    visibly marked, noindexed and excluded from the sitemap; they are never presented
    as real businesses. If a firm finds an error in a verified record, email
    [contact@garagedoorlabs.com](mailto:contact@garagedoorlabs.com) with the
    page URL and the correction; verified corrections are handled first.