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Manual J on iPad Pro, with LiDAR

The load calculation a technician trusts and a homeowner understands.

Scan the house, correct the plan in minutes and get room-by-room heating and cooling loads, the inputs worth checking, right-sized equipment and a report for everyone who needs one.

Join the waitlistSee how it works

Built on ACCA Manual J 8th edition procedures
Built with UniColorado in Denver

calc.blue results on iPad: a floor plan coloured by each room's cooling load, heating 46,820 and cooling 28,180 BTU/h with their likely ranges, and a Verify list ranked by how much each input could swing the load.
The Results step in calc.blue, with sample data.
How it works

HVAC load calculation in one visit

calc.blue follows the job the way you work it: capture the house, check what matters, see the loads, pick the equipment and hand everyone the report they need.

  1. Step 1: Capture

    Walk the house with an iPad Pro. LiDAR picks up walls, windows and doors as you go.

  2. Step 2: Verify

    Sensible defaults fill the gaps, and the few inputs that move the load most come first.

  3. Step 3: Results

    Heating and cooling for every room, with a likely range and the reason behind each one.

  4. Step 4: Design

    Match heat pumps and furnaces to the house at its own design temperatures.

  5. Step 5: Report

    A permit packet, an installer sheet and a homeowner story from the same job.

A scanned single-storey house as a 3D dollhouse in calc.blue, next to the list of captured rooms and their areas.

01

Scan the whole floor in one walk

Walk through the house with an iPad Pro. LiDAR captures walls, windows, doors and ceiling heights room by room, and you leave with a 3D model and a plan you can trust.

  • Rooms, areas and exterior walls counted for you
  • A 3D dollhouse to check the scan before you leave
  • Problems flagged on the spot: open rooms, loose wall ends, tiny scan artifacts

Heating

49,14046,82044,96044,510BTU/h

+2,320 BTU/hAs scanned−1,860 BTU/h−2,310 BTU/h
Attic insulation

Try it: the number above changes as you pick.

UndoFull calculation in the background

Sample house. Illustrative figures.

02

Every edit lands instantly

Change a wall, a window or an insulation level and the loads update right away, on the iPad. The full calculation catches up in the background. No spinners, no save buttons, nothing to wait on.

  • Undo and redo every change
  • Deleting never asks “are you sure?”: it offers Undo instead
  • Autosaved after every edit
“What is the wall built from?”: picture cards for 2×4 framing, 2×6 framing and concrete block, each with how to tell and its effect on heating, plus a Not sure card that keeps the default and widens the band.

CoolingDefault

28,180BTU/h

likely 26–31k

Verify 4 open

ranked by swing

  1. InfiltrationAverage±2.4k
  2. Attic insulationR-19±1.1k
  3. West windowsClear glass±0.9k
  4. Duct locationAttic±0.8k
  • Measured
  • Selected
  • Defaulted
  • Overridden

03

A Manual J load calculation that shows its work

Every value is marked measured, selected, defaulted or overridden, in the app and in the report. Instead of one number you get the load and its likely range, and a Verify list ranks the assumptions by how much they could swing the result, so you check the ones that matter first.

  • Not sure what's in the wall? Answer “what do you see?” with pictures, or choose Not sure
  • Each room explains itself: “West windows are 59% of this room's cooling at 4 pm”
  • Built on ACCA Manual J 8th edition procedures
The calc.blue plan editor: a floor plan with wall lengths, a wall being drawn with a live length bubble, and a list of rooms with their areas.

04

A plan editor that keeps up with you

Fix the scan in minutes on a clean 2D plan, then check it in 3D. Drag walls, type exact lengths and mark what's behind each wall by painting it.

  • Walls snap to corners, 90° and 45°
  • Tap any dimension to type it exactly
  • Draw with Apple Pencil, move around with your finger
  • Garages, attics and unconditioned spaces painted right on the plan
  • Flat, sloped and cathedral ceilings

05

Heat pump sizing with Manual S equipment selection

See each system's capacity against the house across the whole temperature range: where the heat pump carries the house alone, how much backup heat is left on the coldest days, and whether cooling lands in a comfortable fit. All-electric or dual fuel.

  • The best fits first, not a catalogue to scroll
  • Photograph the old unit: “Current unit is 2.1× the design load”
  • Equipment and rebate data from rebate.blue

Equipment fit

Capacity vs outdoor temperature · sample house

Try it
Heat pump size (tons)
Compressor
Backup heat
2.5-ton variable heat pump with electric backup on a sample house: 40.0k BTU/h heating at 3°F, 30.0k BTU/h cooling at 91°F. Balance point 23°F. Below it the electric backup makes up the difference: 4.7 kW at 3°F, where the heat pump covers 60% of the load. Cooling capacity at 91°F is 103% of the load: comfortable fit.010k20k30k40k50k60k−10°F0°F10°F20°F30°F40°F50°F60°F70°F80°F90°F100°FOutdoor temperatureBTU/hDesign low · 3°FDesign high · 91°FBalance point23°F

20°F: house needs 29.0k, heat pump 26.9k, backup 2.1k

Balance point
23°F
Below this, backup heat helps
Electric backup at 3°F
4.7 kW
Heat pump covers 60%
Cooling at 91°F
103%
Comfortable fit

Sample house with generic heat pump curves, for illustration only. In the app, candidates come with real performance data for your design conditions.

  • Permit packet

    Building department

    Load summary, room loads, equipment selection and the provenance legend, in a layout code officials know.

  • Installer sheet

    Install crew

    Room airflow, equipment, duct notes and photos with markup: what the crew needs on install day.

  • Homeowner story

    Homeowner

    Why this size, where the heat goes and what an upgrade would change, in plain language.

06

One job, three reports

The same job becomes a permit packet for the building department, an installer sheet for the crew and a plain-language story for the homeowner. Drafts are ready before you finish, marked with what is left to verify.

  • Share as a link or a PDF, or export all three at once
  • The homeowner story explains why this size, in plain words
Bills vs calculation: four gas bills imply a heating load of 39,940 BTU/h, likely 36–44k, shown next to the calculated load.
Bill check
Nameplate reader: manufacturer, model and serial read from a photo, each marked Measured, and the verdict “Current unit is 1.4× the design load: Oversized”.
Nameplate reader

07

Check the load against the house's own history

Enter a year of fuel bills and see the heating load they imply next to the calculation. Photograph the nameplate and calc.blue reads the model and serial and shows how the current unit compares with the design load.

  • Photos with Apple Pencil markup for the installer sheet
  • A short comfort survey for the homeowner report

Sync, honestly

  • On this iPad onlyNo signal. Everything keeps working.
  • Syncing 3 changesBack online. Catching up in the background.
  • Synced 9:41Only once every change has arrived.

08

Works where the signal doesn't

Basements, attics and rural driveways. Capture, edits, results and draft reports all work offline. Changes stay on the iPad and sync when you are back online, and calc.blue only says Synced when every change has arrived.

  • Dark mode for attics and crawlspaces
  • Large, high-contrast type that reads in a sunny driveway
UniColorado Heating & Cooling

Built with UniColorado, for real Colorado homes

calc.blue is made by DotBlue, a UniCo Group company. Its sister company UniColorado Heating & Cooling is a Denver HVAC contractor, founded in 2014, that installs heat pumps across the Front Range. calc.blue is shaped by what their crews need on site, in Colorado weather.

A Mitsubishi heat pump outside a Denver home, the shrubs around it covered in snow.
Heat pump in a Denver winter. Installed by UniColorado.
A UniColorado pickup parked beside a newly installed heat pump on the side of a red-brick house.
A UniColorado job site in Denver.
A cold-climate heat pump running in falling snow against a brick wall.
Cold-climate heat pump in fresh snow. Installed by UniColorado.
Plenum

Works with Plenum, and the rest of the family

calc.blue connects to Plenum for customers and jobs, and to rebate.blue for certified equipment and rebate data.

Get calc.blue on your next job

Join the waitlist and tell us a little about your work. We'll reach out when there's a spot for you.

  • Early access as we open calc.blue to contractors in small groups
  • A say in what we build next
  • First word on pricing, before anyone else

We only use this to contact you about calc.blue. Privacy

Questions about Manual J, heat pump sizing and calc.blue

What is a Manual J calculation?
Manual J is the ACCA procedure for working out how much heat a home loses in winter and gains in summer, room by room, at the local design temperatures. Building departments often ask for it with an HVAC permit, and it is the starting point for choosing equipment of the right size.
How do you size a heat pump?
Start from a room-by-room load calculation, not the square footage or the old unit's size. Then compare each heat pump's real capacity with the house's heating and cooling loads at your design temperatures, see how much backup heat is needed on the coldest days, and check that cooling is not oversized. calc.blue puts all of that on one chart.
What's the difference between Manual J, Manual S and Manual D?
Manual J calculates the heating and cooling loads. Manual S selects equipment that meets those loads at local conditions. Manual D designs the duct system that delivers the air. calc.blue covers the load calculation and equipment selection, and gives the installer the airflow for each room.
Is calc.blue ACCA-approved?
Not yet. calc.blue is built on ACCA Manual J 8th edition procedures. We will only describe it as approved once ACCA says so.
Which iPad do I need?
calc.blue is an iPad app. Scanning uses the LiDAR sensor, so you need an iPad Pro with LiDAR to capture a house.
Does it work without a signal?
Yes. Capture, edits, results and draft reports all work offline. Changes stay on the iPad and sync when you are back online.
What does calc.blue cost, and when can I use it?
Pricing is not set yet. We are opening access to contractors in small groups. Join the waitlist and you will hear first.
Who makes calc.blue?
calc.blue is made by DotBlue LLC, a UniCo Group company. It is designed around the day-to-day work of crews at UniColorado Heating & Cooling, its sister company: a Denver HVAC contractor founded in 2014.

Guides on HVAC load calculation

Plain-English explainers on Manual J, heat pump sizing and equipment selection.

All guides