Lockwell HVAC
Resources for homeowners
HVAC tools. No signup. No bait.
Two field-grade calculators we use on real Birmingham jobs. The math is ACCA Manual J residential rule of thumb, tuned for Alabama's humid subtropical climate. Free, no email, no “get-a-quote” trap.

Tool · 01
BTU Calculator
Single-room cooling load
Enter room dimensions, ceiling height, insulation, sun exposure, and occupants. Get the required BTU/hr — sized for Birmingham's humid Cfa climate.
Open tool→

Tool · 02
AC Sizing Calculator
Whole-house tonnage & SEER
Enter conditioned square footage, construction year, and insulation rating. Get recommended tonnage, SEER2 efficiency, and R-454B refrigerant guidance.
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When the calculator is not enough
Need a real Manual J?
We measure the house room by room and put the right-size equipment number on paper before any quote.
Call (205) 206-7030