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Offline HVAC field calculator with R-454B PT charts, superheat/subcooling, duct sizing, load estimates & psychrometrics. No subscription, no ads, no tracking. Free PT charts (R-454B/R-32/R-410A) + unit converter. Pro: $9.99 one-time for all calculators, 13 refrigerants & PDF export. 100% offline — built for techs on the roof. Feedback welcome!
Hey Product Hunt! 👋
I'm the solo developer behind FieldCalc HVAC.
This started when I kept hearing the same thing from HVAC techs:
they're switching from R-410A to R-454B refrigerant in 2025-2026,
and none of their existing apps have the new PT data. On top of that,
every calculator app either charges a monthly subscription, bombards
them with ads, or stops working the moment they're on a roof with no
signal.
So I built one app that solves all of it:
• Works 100% offline — no signal needed on the roof or in the
mechanical room
• R-454B PT data sourced from Honeywell/Chemours PT cards + NIST
• 6 calculators in one: PT charts, superheat/subcooling, duct sizing,
load estimate, psychrometrics, unit converter
• Every calculation shows the full formula and substitution —
transparent, not a black box
• One-time purchase, not a subscription. $9.99 once, yours forever.
The free version (PT charts for R-454B/R-32/R-410A + unit converter)
is permanently free — no trial, no time limit.
Zero tracking, zero analytics, zero ads. Your data never leaves
your device.
If you try it, I'd genuinely love your feedback:
1. Does the R-454B PT data match your manifold readings?
2. What calculator or refrigerant is missing?
3. Does the one-time purchase model appeal to you vs subscriptions?
Happy to answer any questions about the app, the tech stack, or the
data sources. Roast it if you want — I can take it. 😄
Thanks for checking it out! 🙏
FieldCalc HVAC was submitted on Product Hunt and earned 8 upvotes and 7 comments, placing #157 on the daily leaderboard. Offline HVAC field calculator with R-454B PT charts, superheat/subcooling, duct sizing, load estimates & psychrometrics. No subscription, no ads, no tracking. Free PT charts (R-454B/R-32/R-410A) + unit converter. Pro: $9.99 one-time for all calculators, 13 refrigerants & PDF export. 100% offline — built for techs on the roof. Feedback welcome!
On the analytics side, FieldCalc HVAC competes within iOS, Productivity and Tech — topics that collectively have 1.4M followers on Product Hunt. The dashboard above tracks how FieldCalc HVAC performed against the three products that launched closest to it on the same day.
Who hunted FieldCalc HVAC?
FieldCalc HVAC was hunted by Eden Lee. A “hunter” on Product Hunt is the community member who submits a product to the platform — uploading the images, the link, and tagging the makers behind it. Hunters typically write the first comment explaining why a product is worth attention, and their followers are notified the moment they post. Around 79% of featured launches on Product Hunt are self-hunted by their makers, but a well-known hunter still acts as a signal of quality to the rest of the community. See the full all-time top hunters leaderboard to discover who is shaping the Product Hunt ecosystem.
For a complete overview of FieldCalc HVAC including community comment highlights and product details, visit the product overview.
Eden Lee