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Free HVAC contractor tools
Browser-based calculators and templates built specifically for 1–5 tech residential HVAC shops. Fast answers, professional output, and zero email gates. Built and maintained by the team behind Ratchly.
Quick answer
Ratchly offers four free HVAC tools for residential contractors: (1) a Manual J-style HVAC load calculator for cooling and heating BTU/hr sizing, (2) an HVAC flat rate pricing calculator that turns hourly costs into profitable customer quotes, (3) a printable HVAC invoice template with refrigerant and equipment fields, and (4) a fillable HVAC service agreement template for recurring maintenance plans. All run in the browser, all are free, and none require an account.
HVAC Load Calculator
Estimate cooling and heating BTU/hr for any home using climate zone, square footage, insulation, windows, and occupants. Recommended tonnage included.
HVAC Duct Calculator
Size supply and return ducts from CFM using target velocity or friction rate. Returns round diameter, next standard size, and rectangular equivalent for any aspect ratio.
HVAC Flat Rate Pricing Calculator
Enter your hourly labor rate, overhead percentage, and part costs to calculate a profitable flat-rate price. Stop under-billing and start quoting with confidence.
HVAC Invoice Template
HVAC-specific invoice with fields generic templates skip: equipment make/model/serial, refrigerant type and pounds, labor and parts split, license number.
HVAC Service Agreement Template
Eight-clause maintenance plan contract: covered equipment, visit scope, member benefits, exclusions, payment, renewal, cancellation, signatures.
HVAC Maintenance Checklist
Spring AC start-up, summer tune-up, fall heating start-up, winter check. Tick tasks as you work, then print or save the signed sheet for the customer.
Why these tools exist
Most "free HVAC tools" online are email-gated lead magnets from enterprise software vendors targeting 50+ tech shops. The Ratchly free tools are built for the other 95% of the industry — the owner-operator and small-crew shops who need a fast calc, a clean invoice, or a real contract today, without giving up an email address or watching a sales demo.
When the tools aren't enough
Templates work until you have more than a handful of customers. Then renewals slip, invoices age past 30 days, and Sundays get eaten by admin. That's when Ratchly earns its keep — built for HVAC shops with 1–5 techs, no enterprise contract.