Effective 10 November 2026.
The Insulation Book gives general information only. It is not professional advice, and it is not a substitute for a qualified professional who has seen your house.
General information only
Everything on The Insulation Book (theinsulationbook.com) is general information, published to help readers understand how insulating and air sealing an existing home works in the US. It is not professional advice of any kind: not building, engineering, electrical, energy, health, legal or tax advice. It does not take your house, its age, its wiring, its heating appliances, its moisture history, your climate or your local rules into account. You are responsible for the work you choose to do and for whom you hire.
Not a contractor, auditor, electrician or asbestos professional
The Insulation Book is not a contractor, an insulation installer, an energy auditor, a home inspector, an electrician, an engineer or an asbestos professional. It is not a building department or a government agency, and it is not part of ENERGY STAR, EPA or the Department of Energy. It never inspects a reader’s house, and it does not look at photos, test or identify materials, review quotes, contracts, receipts or audit reports, or refer anyone to a contractor, installer, auditor, electrician or removal firm. Reading this site, using a calculator or writing to us creates no professional relationship.
No view on your house
Nothing on this site says that your house, your attic, your wiring or a finished job is “up to code”, compliant or safe. Nothing here says what the material in your house is, whether it contains asbestos, how much insulation you must add, which product to buy, whom to hire, what a job should cost or what you will save. Those are decisions for you, with people who have seen the house, and some are decided by your building department.
Codes are adopted locally
Where a page cites the International Residential Code, the International Energy Conservation Code or the National Electrical Code, it cites a model code, by section and by the edition we read. A model code is not the law where you live. States, counties and cities adopt their own editions, often years apart and with their own changes. We do not say which edition is in force in any state or city. Your building department decides which rules apply to your house, whether your job needs a permit, and what an inspector will accept. ENERGY STAR’s insulation levels are recommendations, not a code.
Safety stops
Some of what a reader can find in an old house is not a do-it-yourself matter, and our pages say so. If any of these applies, stop:
- Vermiculite and suspected asbestos. EPA says to assume vermiculite insulation is from Libby, Montana, and to treat it as if it contained asbestos by not disturbing it. EPA’s words: “Do not attempt to remove the insulation yourself” (EPA, read 10 November 2026). We give no steps for disturbing, sampling, removing or covering vermiculite or any material that might contain asbestos, and no page should be read as permission to do so. Work that would disturb it is for a trained asbestos professional.
- Wiring. Knob-and-tube wiring, damaged wiring and recessed light fixtures that are not rated for contact with insulation are fire risks when insulation covers them. We give no wiring or fixture steps. A licensed electrician decides what is there and what can be done.
- Gas and oil appliance venting. Tightening a house changes how furnaces, boilers, water heaters and other fuel-burning appliances draw air and vent, and EPA lists back-drafting from them as a source of carbon monoxide (EPA). ENERGY STAR’s guide says to have your heating and cooling technician check gas- and oil-fired appliances for proper venting after work that makes a house tighter. Keep working carbon monoxide alarms. Clearances around flues and chimneys are set by the vent’s own listing and your local code.
- Spray foam. Two-part spray foam contains isocyanates. We explain what the label and the Consumer Product Safety Commission’s staff say and give no installation walkthrough.
- The attic itself. ENERGY STAR’s guide recommends hiring a contractor to correct these problems before going any further: wet or damp insulation, moldy or rotted rafters or floor joists, kitchen, bathroom or dryer vents that exhaust into the attic, a history of ice dams, little or no attic ventilation, and knob-and-tube wiring (EPA 430-F-04-024, July 2016). Our pages treat each of them as a stop.
The do-it-yourself steps on our pages are the ones ENERGY STAR or the product’s label gives to homeowners. They are not a full set of safety instructions for your attic. The label and instructions on the product in your hands come first.
Sources and figures change
ENERGY STAR’s live tables carry no printed date and can be revised at any time. Model codes come out in new editions. Makers reissue coverage charts and data sheets. The Department of Energy removed its consumer pages on insulation, so we cite dated archived copies. Tax credits end, rebate programs open and run out of money, and energy prices move every month. Each figure on this site shows its source and the day we read it, and it may have changed since. Check the current figure with the original source before you rely on it.
Makers’ figures apply to one product
A coverage chart or data sheet applies only to the product it was printed for, installed the way that sheet says. Bag counts and depths from one maker’s chart do not carry over to another product, or to the same product under a newer chart. The chart on the bag you bought is the one that counts. Naming a product as the source of a figure is not a recommendation of it.
Tools give estimates, not verdicts
Calculators do arithmetic on what you enter and on the tables and charts they name. Their results are estimates. An R-value estimated from the depth of old insulation is rough. A bag count is the chart’s figure for the area and target you entered, not a promise of what your attic will take. A vent area result applies a model code ratio and does not say that your attic is properly vented. A savings figure applies EPA’s model of a typical house, not a measurement of yours; savings vary. No tool says that a house is up to code or safe, and no tool prices a job. Defaults that are our assumption are labelled, and you can change them.
Tax credits, rebates and savings
Notes on the federal tax credit, state rebate programs, weatherization help and the Zonolite Attic Insulation Trust are general and name the law, agency or program page they come from, with its date. They are not tax, legal or financial advice. A program listed as launched may have no money left, and each program decides who qualifies. Ask a tax professional about your own return, and your state energy office about rebates.
Health
Lines about asbestos, mold, carbon monoxide, spray foam chemicals or insulation fibers repeat what EPA, the Consumer Product Safety Commission or another named agency says. They are not medical advice. Ask a doctor about your own health.
Accuracy
Pages are checked against the sources they cite, but no check catches everything. Check important details with the original source before you rely on them. See also our terms of use.
How our content is made
Every page is fact-checked against its sources before it is published. Pages appear under The Insulation Book name. Our editorial policy and how we check page explain the process.
Advertising and independence
The Insulation Book is free to read and funded by display advertising. Advertisers have no say over what we publish, and an ad on a page, including an ad for an insulation maker, an installer or a retailer, is not an endorsement or a referral. 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. Names of makers, products, agencies, programs and code publishers are used only to identify them, and we are not affiliated with them.
External links
We link to agencies, regulations, model codes, makers’ documents and other websites so you can check what we say. We do not control those sites and are not responsible for their content.
Questions and corrections
If you think something is wrong, email contact@theinsulationbook.com with the page address and a source, and we will look at it. We can’t inspect a house, review quotes or recommend contractors. See also our corrections page.