Beta

This calculator works, but its numbers have not yet been checked against another load-calculation tool on a real house. The duct load it adds is a typical fraction keyed on foundation type, not a measurement of your ducts.

The calculation engine has not yet been checked against a reference tool on a real house. Treat every number here as a starting point to verify, not a finished answer.

Check the results before you act on them. Verify against the equipment data plate, the manufacturer's installation manual, and your own measurements. You are responsible for what you install — Cheek Heating & Cooling LLC is not liable for decisions made from this tool's output.

Free HVAC load calculator

ACCA Manual J 8 Abridged Edition method · no signup · download the PDF free

Project

Project name (for your PDF report) Project type

Appliance location

Selects which code subsection the report's access checklist cites — each location carries a different set of requirements. Leave it blank if you don't know: the report will say the location wasn't recorded rather than assume one.

Equipment access and service space (optional)

Measurements taken at the appliance. Everything here is optional and every field may be left blank: a blank field is reported as not recorded, which is not the same as passing and not the same as measuring zero. Fill in whatever you took a tape to.

If the appliance is in an attic

Attic opening, clear width (in) The unobstructed opening, measured after any framing, trim or lining. Attic opening, clear length (in) Solid continuous flooring, width (in) The floored walkway from the opening to the appliance, and the working platform at it.

If the appliance is under a floor

Under-floor opening, rough-framed width (in) The framed opening, before any lining or trim. Under-floor opening, rough-framed length (in) Under-floor opening, clear width (in) The unobstructed opening. Rough-framed and clear are two different measurements taken at two different planes, so both are asked and neither is derived from the other. Record the one you actually took and leave the other blank. Under-floor opening, clear length (in) Clearance above the adjoining ground (in) Passageway or service space depth below adjoining grade (in) Below the code trigger depth the wall-lining requirement does not apply at all, so this figure decides whether the next question is even asked. How the appliance is supported The required ground clearance is not the same figure for the two, and for a ground-supported appliance it is a per-jurisdiction lookup, so no figure is printed here. Without this answer the clearance above cannot be judged at all. Are the passageway or service space walls lined with concrete or masonry extending above grade? Only reachable when the depth below grade above exceeds the code's trigger depth; at or under it the requirement does not apply.

Passageway to the appliance

Passageway height (in) Passageway width (in) Passageway length (ft) Measured in feet, not inches. Does that height and width hold for the entire length of the passageway, not just at the opening? This answers one thing only: entire length, or only at the opening. Answering yes cannot on its own buy the longer-passageway exception, because the height and width you entered above still have to clear that exception's own higher bar, and the checker re-reads them to decide. Where the exception does apply it raises or removes the length limit, so answer it honestly.

At the appliance

Working space at the appliance, depth (in) Level working space in front of the service side. Working space at the appliance, width (in) Largest appliance footprint, width (in) Used to check that the opening is large enough to get the appliance back out. Leaving this blank does not make the opening pass -- it makes that clause unevaluated, and the report says so. Largest appliance footprint, length (in) If the appliance is in a room or basement, does that room have a door?

Getting the appliance back out

Can the appliance be serviced and removed entirely through the opening, without entering the space? Answer yes only if it is true. Yes invokes the code exception, and the checker then stops evaluating the passageway geometry below rather than reporting it. Does removing the appliance require removing permanent construction? Does removing the appliance require removing another appliance first? Whether this is a defect depends on the jurisdiction, which the report resolves; record what is true on site either way.

Light and power at the appliance

Is there a lighting switch at the access opening? Is there a receptacle outlet near the appliance? Are exposed lamps protected from damage?

Property address

Start typing — suggestions appear for most addresses. Rural addresses (county roads, route numbers): type the full address and press Enter. · searching…

📍 Find your house

Type your address → the map zooms to your area. Then zoom in until you can see your house on the satellite, click ＋ Draw living space below, and drag a box over the house. Use − Exclude garage/porch to carve out unheated space.

⏳ Looking up your address…

✅ Found: · Auto-traced footprint: (-story estimate) · Click ＋ Draw living space below to mark your house footprint.

📑 Public record (IndianaMap): Parcel , , , . The yellow dashed outline on the map is your property line.

⚠ Couldn't locate that address. Try a more specific street + city + ZIP, then click .

Satellite (draw on this) Esri World Imagery · right-click-drag rotates ↻

↓ Zoom in, then click ＋ Draw living space below

Street view (visual check) Google Maps

Type your address above — Street View will load here so you can confirm we found the right house.

Floor area for calc: (excludes sqft for garage/porch)

Stories:

⚠️

Double-check the auto-traced outline. Use ＋ Draw living space to trace just the heated footprint of your home.

How do I exclude the garage?

1) Zoom in on the satellite map until you can clearly see your house. Rotate if it helps: hold the right mouse button and drag (two-finger twist on touch) until the house sits square on screen — the compass button (top-right of the map) snaps back to north. 2) Click ＋ Draw living space — drag a rectangle over just the house footprint (not the whole lot). For an L-shape, draw a second living-space box over the other wing, or use ⬠ Trace outline to click corner-by-corner around the exact shape (click the white dot to close it). 3) Reshape it: click a shape to select it, then drag the corner handles (the small dots between corners add new corners). The total updates as you drag. 4) To exclude an attached garage or porch: click − Exclude garage/porch and drag a red box over it. Only the part overlapping your living space is subtracted — a detached garage never counts, so excluding it changes nothing. 5) Picked the wrong color? Click the shape, then use ⇄ Exclude selected / ⇄ Count selected as living space in the toolbar to flip it (green = counted, red = excluded). 6) Set Stories (1/2/3) next to the total — for a 2-story home the calc needs footprint × 2. Then click Use this measurement.
Tip: clicking any empty spot on the map shows the parcel info for that property (lot line, address, acreage).

Found your house on the map above? Continue. Or skip it — see below.

We'll ask a few quick visual questions next. No technical knowledge needed.

Address won't pull up? Skip the map.

The satellite map is only a shortcut to estimate your square footage — you can type that in yourself on the next step. Just enter your ZIP code so we use the right climate design temperatures for your area.

ZIP code

Your home, as you've described it

📐 sqft floor area

🧱 walls

🏠 ceiling

🟫

🪟 windows

📅 era construction

Building envelope

The "envelope" is your house's outer shell — walls, attic/ceiling, floor, windows. The better insulated it is, the smaller HVAC system you need.

What's R-value?

R-value = "Resistance to heat flow"

R-7: A thin layer of old fiberglass — leaks heat fast
R-13: 3.5" batt in a 2x4 wall — typical 2x4 construction
R-19: 6" batt in a 2x6 wall — typical upgrade
R-30: 10" of attic insulation — common in newer homes
R-38: 13" of attic insulation — common in newer construction

Higher R = better. Doubling R-value roughly halves heat loss.

Floor area (sqft) Ceiling height (ft) Stories Envelope tightness class (optional — overrides the era) Fireplaces (open hearth or vented gas) Blower-door CFM50 (only if tested) Occupants (people living here) Bedrooms (optional) Sets the mechanical-ventilation rate. Left blank, we estimate it from the occupant count.

When was your home built?

Pick the era — we'll set sensible defaults for insulation and air-tightness. Override below if you know specifics.

Wall insulation

Pick the closest match. The cross-section drawing shows the wall slice from outside (left) to inside (right) — siding, sheathing, stud + insulation, drywall. Thicker yellow = more insulation.

Attic / ceiling insulation

Walk up there with a tape measure if you can. The drawing shows the attic insulation depth — taller yellow/peach layer = more R-value.

Floor type

What's under the lowest level of conditioned space? The drawing shows the finish floor + joist cavity above the crawl / basement / garage / slab below.

Window type

What kind of windows does your home have? This affects how much heat escapes in winter and how much sun comes in during summer.

Window areas (by orientation)

Quick mode (total sqft only) Room-by-room mode (more accurate, more typing)

Add each window opening below for the whole house. U-factor and SHGC default from the window type you picked above; override if the unit's NFRC sticker says otherwise.

Quick mode: just type total window sqft per direction. We'll apply U= and SHGC= based on your window-type pick above. Starting values assume windows ≈ 15% of floor area (a common-construction default) and track your floor area until you edit them.

Whole-house glazing below is ignored when room-by-room mode is on. Define rooms in the section below.

Rooms

Define each conditioned space. Walls + ceiling + floor U-factors come from the whole-house values above. Per-room glazing drives the room's solar gain and final per-room CFM (for Manual D branch sizing).

No rooms yet. Click + add room.