The Difference Calculator
Everybody asks me the same question, on almost every reel and every phone call:
“How much extra does it cost to build a super energy-efficient and healthy home?”
I will be straight with you. That question was hard to answer, and it took a long time to get this figured out. Every house is different. But you have to start somewhere, so start here.
Type in the size of your building and how many windows and doors it has. The calculator does the rest. It shows you the extra cost on your house, at your prices.
It is free. Use it as many times as you want. And you get the free Carbonless newsletter starting in January.
Affordable housing matters.
Affordable living matters more.
A house that is cheap to build but expensive to live in every month is not affordable.
The first page is one page. Nine yellow boxes. You type in your building size, your windows and doors, your utility bill and your mortgage rate. The green boxes give you the answers.
You see the extra cost of materials for a better wall, what that adds to your mortgage each month, and what could be left over each month if your utility bill goes down.
Behind that first page, the calculator prices the same walls twice:
A wall built to code, the legal minimum
A Carbonless wall, with at least R-10 of insulation on the outside
Then it shows you the difference. Here is the good news: a better wall does not need big, expensive name-brand products. It needs the right layers, in the right order.
Materials only. No labor. It is a learning tool, not a bid or a promise. But it gives you a real place to start the talk with your builder, your banker and your family.
What it helps you figure out
Before you build, or before you sign a bid, it helps you see:
How much the extra insulation on the outside of the wall costs
How much your insulation choice changes the price
How many sheets, rolls, tubes, panels and fasteners to buy, on a shopping list you can print
How the extra cost compares with the utility bill you are aiming for
What the upgrade costs per square foot of wall
What the better wall adds to a mortgage each month
What to gather so your heating and cooling can be sized right (Manual J)
Plus: the free Carbonless newsletter
When you get the free calculator, you also get The Carbonless Report, a free monthly newsletter by email starting in January 2027.
Every issue has real jobs, real photos and plain answers: what went wrong in a house, why it happened, and how it was fixed. You will also meet the builders, remodelers and other professionals who are Carbonless members.
Here is a first look at Issue 01. It is still a draft, so pages may change before it goes out.
Free. No cost, ever. You can unsubscribe any time.
The real question is not only,
“What does it cost to build?”
The better question is:
“What does it cost to live in?”
Get it free. Then, when you want to know why the numbers come out the way they do, the list on this page shows where to go next.
Everybody asks the same question: how much extra does it cost to build a super energy-efficient and healthy home? It took a long time to get this figured out. Every house is different, but you have to start somewhere. Start here. It is free, and you also get The Carbonless Report, a free monthly newsletter starting in January 2027. Two free gifts with one sign-up.
The first page is one page. Nine yellow boxes for your numbers. The green boxes give you the answers: the extra cost of materials for a better wall, what that adds to your mortgage each month, and what could be left over each month if your utility bill goes down.
Behind that first page, for builders and anyone who wants the details:
• A worked 40′ × 60′ barndominium example
• Every price in a yellow box, so you can use your local prices
• A wall built to code next to a Carbonless wall, line by line
• A shopping list you can print and take to the store
• Insulation choices and a spray foam calculator
• A Manual J load calculation on its own tab. It works out the heating and cooling load. A licensed heating and cooling contractor still picks the equipment.
Materials only. No labor. The calculator estimates building costs and possible monthly operating costs from your inputs and its assumptions. A Manual J load calculation is not a full yearly energy model, and it is not a promise of any utility bill. This is a learning tool, not a bid, an engineering report or a code approval.
Download your files within 24 hours of opening the link. Once downloaded, they’re yours to keep. Inside, a GET HELP — WORLDWIDE tab shows where to turn next: email hello@carbonless.org, or find a member near you in the Carbonless Directory.
When you want to know why the numbers come out the way they do, here is where to go next:
• THE BOX — Complete Edition, $49.99 hardcover. Three books in one. The first book to buy before you build, remodel or fix.
• Wall and Roof Assembly Library, $349 hardcover. 863 wall and roof assemblies in 776 pages, with whole-wall R-values, so you can compare walls before you pick one.
• The Super Energy-Efficient & Healthy Home Field Guide, $299 hardcover. Real walls being built, with photos.
• The NightMare, the Retrofit & Remodel Field Guide, $249 hardcover. For the house you already own.
• Super Energy-Efficient Building Audio Course, $99. Listen while you drive.
• Carbonless 2126, 40 courses. The first course is free.
• Carbonless Membership. The complete education, the Carbonless Roundtable and the Directory.
• Consulting with Brian, when you have a question about your own building.
Questions? Email hello@carbonless.org.