HVAC Design Studio

Free HVAC load calculator

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

Project

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.

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 — modern code minimum
  • 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 — Indiana code minimum

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

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)

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.