Built for HVAC techs & sheet metal shops

IronKit for HVAC —
AI Load Calculator & Estimating

Run room-by-room Manual J load calculations. Size duct runs. Generate professional quotes. IronKit gives HVAC contractors the tools to size equipment correctly, bid accurately, and stop guessing on sizing.

Start 14-day free trial Try free HVAC calculator →

No credit card required · All 15 tools included

2 min

Room-by-room load calc

AI tools in one subscription

$29

per month, all tools

Tools for your trade

Everything an HVAC contractor needs

From load calculation to equipment sizing and duct design — IronKit covers the estimating and documentation side of every job.

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HVAC Load Calculator

Room-by-room Manual J style load calculation — BTU/hr cooling and heating, equipment tonnage, CFM, and duct size per room. 15 ASHRAE climate zones covered. Save every calc, get a branded PDF.

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Quote Writer

Describe the HVAC scope — new installation, replacement, retrofit — and get a professional quote in seconds. Includes labor, equipment, materials, overhead, and markup. Shareable link or PDF.

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Blueprint Analyzer

Upload equipment plans or specifications and IronKit extracts unit sizes, duct routing, and material quantities — then formats an equipment takeoff for your estimate.

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Change Order Generator

Scope creep on a retrofit? Generate a professional change order with cost justification, original contract reference, and adjusted totals. All change orders tracked in your account.

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See it work

Room-by-room load calculation — done

Here's what IronKit's HVAC Load Calculator returns. Enter your rooms, insulation levels, and climate zone. Get the full Manual J output in 2 minutes.

HVAC Load Calculation — IronKit Output

HVAC LOAD CALCULATION
Project:    Residential Replacement — Fort Worth, TX
Climate:    ASHRAE Zone 2A (Design: 95°F DB / 75°F WB)
Date:       May 28, 2026
Method:     Simplified Manual J (8th Edition)

ROOM-BY-ROOM SUMMARY
Living Room:  420 sqft | 14,800 BTU/hr | 2.0 tons | 380 CFM | 10" duct
Master Bed:   280 sqft |  9,200 BTU/hr | 0.8 tons | 232 CFM |  8" duct
Bedroom 2:    200 sqft |  6,600 BTU/hr | 0.6 tons | 166 CFM |  6" duct
Kitchen:      160 sqft |  8,400 BTU/hr | 0.7 tons | 178 CFM |  7" duct
Bathroom:     100 sqft |  3,100 BTU/hr | 0.3 tons |  78 CFM |  6" duct

SYSTEM RECOMMENDATION
Total Cooling:     42,100 BTU/hr → 3.5-ton system (oversize check: 103%)
Total Heating:     38,200 BTU/hr
Design CFM:       1,034 CFM @ 400 CFM/ton
Friction Rate:    0.09 in.wc / 100 ft

✓ All 5 rooms within 115% Manual J limit
✓ Duct schedule generated

See 46 more example outputs →

Pricing

One plan. Every tool.

No per-document fees. No per-user seats. One flat rate covers every tool.

IronKit — All Tools

$29/month

$290/year (save $58)

HVAC Load Calculator (Manual J style)
Room-by-room BTU/hr + duct sizing
Quote Writer — unlimited HVAC bids
Blueprint Analyzer & equipment takeoff
Change Order Generator
Daily Field Report Generator
Toolbox Talk Generator (OSHA-ready)
Shareable client links + PDF exports
Custom shop branding on all documents

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No credit card required. Cancel anytime.

FAQ

Questions from HVAC contractors

Does IronKit calculate HVAC loads like Manual J?

Yes. IronKit uses simplified Manual J methodology — room-by-room BTU/hr calculation accounting for climate zone, insulation levels, window type and area, infiltration, and internal gains. It returns cooling load, heating load, equipment tonnage, CFM, and a duct size per room using a 0.09 in.wc/100 ft friction rate target.

How does IronKit size ductwork?

IronKit generates a duct schedule per room — round duct diameter and rectangular equivalent based on calculated CFM. Friction rate defaults to 0.09 in.wc/100 ft per ACCA Manual D. Branch velocities stay within 600–900 FPM. Main trunks at 700–1,000 FPM.

Can I use IronKit for replacement HVAC sizing?

Yes. For replacement work, enter room dimensions, insulation levels, and window specs. IronKit calculates the load and recommends equipment tonnage. Always stay within 115% of the calculated cooling load — oversized systems short-cycle and fail to dehumidify.

Does IronKit replace a full Manual J calculation for permits?

IronKit uses simplified Manual J methodology — accurate for preliminary sizing and contractor field work. For permit-required calculations or energy code compliance, use ACCA-certified software or a licensed mechanical engineer.

Is there a free trial?

Yes — 14 days with full access to all 15 tools. No credit card required. After the trial, $29/month covers everything.

IronKit for HVAC —AI Load Calculator & Estimating