The calculator is free
Every app ships an Apprentice tier. GasLogic Quick Calc is usable on day one — three sequential trunks, a Jobber preview, and a Canvas session before you pay anything.
BTU Engineer · Peak Eleven
Trade calculators built for the truck, not a desktop CAD seat.
GasLogic, DuctLogic, and NoteLogic are live. Every app starts free — paid unlocks stay inside each app. One optional master plan unlocks the whole suite.
9:415G
Quick Calc
NG sequential trunk
Load
248,000 BTU
Length
86 ft
Drop
0.5 in WC
Size
1-1/4" CSST
Furnace branch
1" · 85k BTU
Water heater
3/4" · 40k BTU
About Us / Our Story
Built because field sizing still lives in spreadsheets and guesswork.
Peak Eleven built BTU Engineer the same way we built PlowProof: one job, done right. You do not buy each calculator on this website. Open the app, use the free tier, and upgrade in-app when a job needs export or unlimited files. The $19.99/mo master plan is the only subscription sold here.
Why BTU Engineer
Use the tool. Pay only if the shop outgrows the free tier.
Built by a trade shop, not a CAD vendor
Sizing, BOM, and plan markup that match how pipe and air actually get installed. Upgrade inside the app when a job needs export or unlimited files.
One Peak Eleven account
Sign in once. Launch GasLogic, DuctLogic, NoteLogic, and every upcoming calculator on the same Peak Eleven account.
The lineup
GasLogic, DuctLogic, and NoteLogic are live.
Live now
GasLogic
GasLogic is built for gasfitters who size pipe in the truck, mark up plans on site, and hand a material list to the supply house — without a bloated CAD seat.
What you get
Quick Calc
Single runs, sequential trunks, and multi-pipe chains with live capacity. Seed the result straight into a job file.
Job Wizard
Job info, attached schematics, and an automated material list. Export PDF, Word, and Excel with Maxitrol regulator auto-selection.
Blueprint Canvas
Visio-style MEP overlay: live BTU and pressure-drop sizing, auto-90s, vent manifolds, municipal start points, and material color presets.
Live now
DuctLogic
DuctLogic is the sister engine for air: size trunks and branches, hit static-pressure targets, and mark supply/return on the same kind of plan overlay gasfitters already use in GasLogic.
Airflow calculator
CFM, FPM, and BTU flow for supply and return — the same “run the numbers, then drop it on a job” workflow as GasLogic Quick Calc.
Duct sizing
Trunk and branch sizing against friction and static-pressure targets so the box on the plan matches the equipment pick.
Canvas overlay
Three-column HVAC canvas for marking duct on blueprints, with a free preview tier when the beta opens.
Live now
NoteLogic
NoteLogic is the shared notebook for BTU Engineer — quick capture on site, checklists, images, and tables that stay with the same account as GasLogic and DuctLogic.
Quick capture
Dictate and jot notes without leaving the truck workflow.
Notebook
Pinned notes, groups, tags, and calendar day items.
Collaboration
Foreman sharing invites — same Peak Eleven login across the suite.
Coming later
Same suite. More trades.
Pricing
Start free in each app. Master plan unlocks everything.
Per-app plans are not sold on this website. The $19.99/mo BTU Engineer master plan is the only subscription here — it unlocks every app.