The Insulation Book

Editorial Policy

How The Insulation Book researches, writes, fact-checks and corrects its pages, which sources it uses, and the safety rules that every page follows.

The Insulation Book pages are written to be accurate, useful, calm about risk, and honest about where each figure comes from and what a page cannot know about your house. This page sets out how that works and where its limits are.

General information, not professional advice. Building codes are adopted locally, with changes, and your building department decides what applies to your house. Where one of our pages marks a stop, stop and call a qualified professional.

How a page is made

  1. Research. We start from ENERGY STAR’s tables and guides, EPA and Consumer Product Safety Commission pages, the Code of Federal Regulations, the Department of Energy’s archived pages, the model codes by section and edition, official state rules and makers’ own data sheets, and note what they do and do not settle.
  2. Writing. A draft is written from that research under The Insulation Book name.
  3. Fact-check. A separate check compares each R-value target, thickness, bag count, clearance, vent ratio, percentage, price, date, code section and safety line with its source, and reworks every sum on the page.
  4. Graphics. Any charts or diagrams repeat figures from the text and add no new facts. Every target, count, clearance or ratio in a graphic shows its source and its edition or date, and targets show their climate zone. No graphic shows a step the source does not give, and none shows vermiculite or suspected asbestos being handled.
  5. Final review. A last read looks for errors, gaps and anything that could mislead someone about a clearance, a stop or what a figure applies to. If it finds a serious problem, the page is fixed and reviewed again. We do not publish a page with a serious problem still open.

Each page ends with the date its sources were checked. No process catches everything, so please tell us if you find a mistake.

Our sources

Every R-value target, thickness, bag count, clearance, ratio, percentage, rule, price and date links to a primary source at the claim: ENERGY STAR, EPA, the Consumer Product Safety Commission, the Federal Trade Commission’s R-value Rule and the other federal rules in the Code of Federal Regulations, the Department of Energy, the IRS and the public laws, the Energy Information Administration, the Pacific Northwest National Laboratory’s climate zone guide, the model codes by section and edition, state rules in official text, and makers’ own data sheets and coverage charts, named by product, publication number and date. If we cannot confirm something, we leave it out or say plainly that it was not read. Our how we check page explains how each kind of fact is handled and lists the documents we use.

Contractor, installer, spray foam and removal company pages, retailer how-to pages and question boards, forums, videos, cost guides, lead-generation sites and trade press are never a source, not for a rule, a figure, an example or a statistic. A maker’s own data sheet hosted on a retailer’s site is used as the maker’s document, and we say so. Claims from sellers appear only as claims we have checked, without naming the seller. Where we point to a building-science publisher, a consultant or a trade group for further reading, we label it as that, and no figure on a page rests on it.

Rules for every page

A wrong clearance can start a fire, a disturbed attic of vermiculite can put asbestos fibers into a house, and a tightened house can pull carbon monoxide back down a flue. So every page follows these rules:

  • A clear note near the top. Every page says it is general information, not professional advice, that building codes are adopted locally and your building department decides, and that you should stop and call a qualified professional for anything the page marks as a stop.
  • Steps only where the source gives them. A page gives do-it-yourself steps only where ENERGY STAR or the product’s label gives them to homeowners, and it carries ENERGY STAR’s list of conditions that call for a contractor first. We add no steps of our own.
  • Vermiculite and suspected asbestos are never disturbed. We follow EPA’s wording without softening it: assume vermiculite contains asbestos, leave it alone, and don’t remove it yourself. No page gives steps for sampling, removing or covering it.
  • Two-part spray foam kits are explained, not walked through. Pages say what the label and the Consumer Product Safety Commission’s staff say. They give no installation steps and rank no kits.
  • Knob-and-tube wiring means a licensed electrician. No page tells a reader to insulate over or around it, and no page gives wiring steps.
  • Recessed lights keep their clearance. Insulation stays 3 inches away from fixtures that are not rated for insulation contact, as ENERGY STAR’s guide says, and pages give no fixture or electrical steps.
  • Air sealing ends with the venting check. Every air sealing page says to have a heating technician check the venting of fuel-burning appliances afterwards, and to keep working carbon monoxide alarms.
  • One target table, with its rivals named. ENERGY STAR’s retrofit table is the target. The model code’s minimum for new homes is shown beside it and labelled, and older figures still found online are explained, never used.
  • Codes as model codes. Code sections are paraphrased and cited with the edition we read. Pages never say “up to code”, “code-compliant” or “safe” about a reader’s house, and never name the edition in force in a state or city.
  • No figure we did not read. A figure appears only if we read it in its primary source. Anything else is left out or marked “not read”.
  • No prices for jobs, no rankings, no referrals. We give no installed prices, rank no products and name no contractor, installer, auditor or removal firm. Where help matters, pages name the kind of help: the building department, a licensed electrician, a trained and accredited asbestos professional, a heating technician.
  • Sums, not verdicts. Calculators say “estimate”, show their working and name their source table and its date.

What we do not claim

  • We are not a contractor, an installer, an energy auditor, an electrician or an asbestos professional, and we never inspect a reader’s house.
  • We do not claim to have installed, tested or inspected the products and jobs we describe.
  • We do not invent authors, quotes, homeowner stories, test results or reader comments.
  • We do not rank or recommend products, makers, installers or contractors, and we do not call anything “best”.
  • We give no savings figure without its source and the words “savings vary”.
  • Photos are stock images chosen to illustrate a topic. They do not show houses or jobs we know of. A maker’s name visible on a product in a photo is not a recommendation, and we do not use images meant to frighten.

Fairness

Insulation is mostly a question of comfort and energy, with a few real hazards at the edges, and we try to write about both in proportion. We don’t use scare words about materials, and we don’t call a material harmless where the agencies stop short of that. Contractors and makers are neither villains nor friends: we report what a maker’s sheet says as the maker’s figure and what a seller says as a claim. Where primary sources disagree, such as on an attic target or on whether to test vermiculite, we show both, say which we follow and why, and do not paper over the gap. Sometimes the honest answer is that your building department, an electrician or the label on the product has to answer the question.

Calculators

Our calculators are formulas with named inputs and shown working, and each formula is checked against answers worked by hand before it goes live. They use the tables and charts they name, with their dates, and the numbers you enter. A product appears in a tool only if we read its maker’s chart, and it appears as data, never as a pick. Every default that is a rate or a rule says where it comes from, or that it is our assumption, and you can change it. Prices are yours to enter. Results are estimates, never a statement that a house meets a code or is safe.

Updates and corrections

Tables, codes, makers’ charts, prices and programs change, so pages are rechecked on the schedule set out on our how we check page, and sooner when we learn a source they rely on has changed. A page shows an updated date only when its content really changed. Errors are fixed and recorded on our corrections page.

Advertising and independence

Display advertising pays for this site, and advertisers have no say over what we publish. We use no affiliate links, accept no paid placements, sell no leads, rank no products, and make no referrals to contractors, installers, auditors or removal firms. Our about page has more on how the site works.