Every R-value number. One app. Works offline.
Smart Insulation Calculator is a 34-calculator estimating toolkit for insulation contractors, energy auditors and weatherization crews - and straightforward enough for a homeowner doing their own attic. No sign-in, no account, and no signal required. It all runs on your phone, which matters when you are standing in a crawl space.
WHY IT IS DIFFERENT
Nobody buys "some insulation". You buy enough to hit a target R-value. So every quantity in this app follows the same visible chain:
Target R-49 → cellulose R-3.5/in → 14.0 inches → 1,000 sq ft → 40 bags
You see the reasoning, not just the answer, so you can show a customer why the number is the number. Switch material and the whole chain re-runs.
THE ENVELOPE
✓ Wall batt calculator - net of windows and doors, batt width from stud spacing
✓ Attic blown-in - bags off the coverage chart at depth, with cellulose settling
✓ Attic batts and rolls - first layer in the bays, second cross-laid over the joists
✓ Cathedral and vaulted ceilings - what R actually fits, minus the vent gap
✓ Floor and crawl space batts - including the support wires that hold them up
✓ Crawl space encapsulation - wall board, ground barrier, seam tape, fasteners
✓ Basement walls - rigid board against concrete plus a framed wall inside it
✓ Rim and band joist - cut board per bay, or spray foam by the board foot
✓ Dense-pack retrofit - pounds and bags by density, plus drill holes per bay
✓ Garage and bonus room - walls, ceiling and door kit as one aggregated job
MATERIALS AND BARRIERS
✓ R-value stack - add layers, get total R and U for the whole assembly
✓ Climate zone lookup - code minimums by IECC zone, assembly and code year
✓ Spray foam - board feet, open cell against closed cell, DIY kits or bulk
✓ Rigid foam board - sheets, seam tape, adhesive, with the polyiso cold derate
✓ Mineral wool, radiant barrier, vapour barrier - including which side it goes on
✓ Attic ventilation - net free area, soffit and ridge split, baffle count
✓ Duct and pipe insulation, plus a soundproofing assembly
PERFORMANCE AND ENERGY
✓ Air sealing kit - caulk, foam, gaskets and covers for the highest-return step
✓ Heat loss and BTU - conductive loss per surface, so you know what to fix first
✓ Savings and payback - before and after R, estimated annual saving, payback
✓ Cost per R - which material is genuinely the cheapest path to your target
✓ Existing R estimator - measure what is there, see the gap to code in one tap
✓ Removal estimating and a 25C-style tax credit checker
COSTS AND QUOTING
✓ Labour by square foot, hour or bag, with an honest attic-access factor
✓ Material cost against your own saved price book
✓ Markup and margin - and the difference between them, which costs people money
✓ Customer quotes, PDF export, shopping lists and quoted-against-actual tracking
WHO IT IS FOR
Insulation contractors quoting several jobs a week. Energy auditors who need to hand a homeowner a defensible number. Weatherization crews. Remodelers pricing a retrofit. And homeowners working out how many bags an attic takes before driving to the store.
BUILT FOR THE JOB
✓ Dark by default, because attics and crawl spaces are dark
✓ Type what your tape says: 12' 6-1/2" - no decimal conversion in your head
✓ Safety warnings where they matter: IC-rated fixture clearances, flue standoffs, and a hard stop on knob-and-tube wiring and vermiculite
✓ Four reference screens: R-value chart, climate zone table, safety guide, converters
FREE, AD-FREE OR PRO
All 34 calculators are free forever. Ads support the free tier. Remove Ads Forever is a one-time $2.99. Pro Contractor ($14.99, one time, no subscription) adds unlimited saved projects, branded PDF quotes with your logo, CSV price book import and export, saved assembly templates and home-screen widgets.
R-value recommendations and coverage figures are reference defaults. The manufacturer's coverage chart governs quantities - always verify local code.
Recent changes:
A rebuilt home screen.
Your current job is now the first thing you see - name, calculations and running total, one tap to open it.
Browse by category instead of scrolling 34 tiles: Envelope, Materials & Barriers, Performance, Costs & Business. Each opens a list saying what every calculator does.
The R-value chart, climate zones, safety guide and converters are now on the home screen instead of buried in More.
On tablets the home screen lists every calculator too.
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