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 house outline below, and drag a box over just the house. Add a second box to exclude the garage.

⏳ Looking up your address…
✅ Found: · Auto-traced footprint: (-story estimate) · Click ▭ Draw house outline 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
↓ Zoom in, then click ▭ Draw house outline 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)
How do I exclude the garage?
1) Zoom in on the satellite map until you can clearly see your house. 2) Click ▭ Draw house outline below — drag a rectangle over just the house footprint (not the whole lot). 3) Reshape it: drag the little square handles on each corner to fit the outline to your house. The total updates as you drag. 4) To exclude a garage or porch: click ▭ Draw house outline again and drag over it. That shape turns red (excluded from the total). 5) Click the middle of any shape to toggle it between included (green) and excluded (red). 6) When the "Floor area for calc" total looks right, click Use this measurement. (For a 2-story home, that number is the footprint × stories — the area the calc needs.)
Tip: clicking anywhere 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.

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.