🔥 FLORIDA GAS PLUMBING

Gas Line Sizing for Tankless Water Heaters

BTU demand calculator, CSST vs rigid pipe selector, FL permit guide — size your gas line right the first time

⚙️ Gas Planner
🔥 BTU Calc
📋 FL Code
📞 Quote

⚙️ Gas Line Sizing Planner

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Total BTU Demand
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Min Pipe Size
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Meter/Regulator Size
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Line Pressure

📊 Pipe Sizing Quick Reference

Natural Gas — 0.5" WC pressure drop, specific gravity 0.60

Pipe Size10 ft50 ft100 ftMax BTU
½"172k95k66k172k BTU
¾"360k199k138k360k BTU
1"678k374k259k678k BTU
1¼"1,290k714k494k1.29M BTU
1½"1,960k1,080k748k1.96M BTU

🔥 Whole-Home BTU Demand Calculator

Calculate total simultaneous gas demand for all appliances

Total Connected Load
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Design Demand: —

⚡ Common FL Tankless Models — BTU Reference

Rinnai RU199iN / RU199eN

NG 199,000 BTU 9.8 GPM

Most popular residential. Requires ¾" gas min. 2" PVC or stainless exhaust. FL rebate eligible.

Navien NPE-240A2

NG/LP 199,900 BTU 11.2 GPM

Built-in recirculation pump. Popular in FL for solar-assist systems. ¾" gas line minimum.

Takagi T-KJr2-IN

NG 140,000 BTU 6.6 GPM

Compact, good for 1–2 bath homes. ½" gas acceptable under 25 ft. Budget-friendly FL option.

Rheem RTG-84XLN

NG 180,000 BTU 8.4 GPM

Most sold at FL big-box stores. ¾" gas required. ENERGY STAR certified, utility rebate eligible.

📋 FL Gas Code — Tankless WH Requirements

Florida requires a permit for ALL gas appliance installations — including tankless water heater replacements. No exceptions under FPC 106.
Pull a Plumbing/Gas Permit (FPC 106.1) — Required for new tankless installation, gas line extension, and meter upgrades. Submit load calculation showing BTU demand. Florida does NOT allow unlicensed gas work.
CSST Bonding (NFPA 54 / FL Amendment) — All CSST must be bonded with #6 AWG copper wire to electrical panel ground. Florida enforces this strictly — it is code, not optional. Required within 6 ft of meter.
Earthquake/Flexible Connector at Unit (ANSI Z21.69) — Appliance connector must be listed, max 3 ft, cannot pass through walls. Must be stainless corrugated type — rubber hose prohibited for FL installations.
Seismic Shut-Off Valve — Not required in FL (no seismic zone), but excess-flow valve (EFV) is recommended by utilities. Many FL gas utilities (FPL, TECO) require EFV at meter on new installs.
Venting — Direct-Vent Required (FL IRC G2427) — Must use manufacturer-approved direct vent or power vent. Category III or IV stainless flue. Cannot vent into chimney with other appliances unless listed for combined use.
CO Detector (FL SB 528) — Required in all sleeping areas within 10 ft if gas appliance installed after 2012. Tankless WH replacement triggers inspection for CO detector compliance.
Pressure Test (FPC 406.4) — All new gas piping must be pressure-tested at 1.5× design pressure minimum — typically 3 PSI for residential. Test must be witnessed by inspector. New CSST runs require separate pressure test.
Water Heater Permit Placard — FL law requires completed permit placard attached to unit. Annual inspection not required, but placard must remain visible per FL Statute 553.73.

🔧 CSST vs Black Iron — FL Comparison

CSST (Corrugated Stainless Steel Tubing)

Faster Install Must Bond Flexible

Best for retrofit in FL concrete block homes. Runs around corners, through walls without fittings. Bonding required at entry point. Approved brands: Gastite, TracPipe, CounterStrike. Do NOT use CounterStrike in exterior exposed locations (UV).

Black Iron Pipe / Schedule 40

Most Common No Bonding Issue More Fittings

Standard for exposed or mechanical room runs. Requires pipe dope or yellow Teflon tape on all fittings. FL humidity causes exterior rust — paint or coat exposed runs. Cannot use in direct contact with concrete slab.

PE (Polyethylene) — Underground Only

Underground Not Indoor FL Code OK

Used for utility company service laterals and exterior yard runs. Cannot penetrate building without transition to metallic pipe at entry point. HDPE is not permitted for gas in FL.

✅ Pre-Inspection Checklist

Gas permit pulled from local building department
BTU load calculation submitted with permit application
CSST bonded with #6 AWG copper to electrical ground
Listed appliance connector, max 3 ft, not through wall
Pressure test completed at 1.5× design pressure (3 PSI min)
Direct vent or power vent properly terminated exterior
CO detector within 10 ft of all sleeping areas
Shut-off valve within 6 ft of unit, accessible

🏡 FL County — Inspector Notes

📞 Get Your Gas Line Sizing Quote

Licensed CPC/master plumber — FL state certified gas piping

⚠️ Gas work requires a licensed plumber or gas contractor in Florida. Never hire unlicensed — it voids insurance and your homeowner's policy.
📞 Call Now: (561) 316-7450

💰 FL Gas Line Sizing — Cost Guide

Gas line extension (10–25 ft)$350–$650
Gas line extension (25–50 ft)$600–$1,100
Gas line upgrade (upsize run)$800–$1,800
Meter upgrade (utility coordinated)$200–$500 + utility fee
CSST bonding (existing system)$250–$450
Full install (tankless + gas line)$1,800–$4,500
Permit fee (FL average)$85–$250
FL FPU / TECO meter upgrade feeOften waived for high-BTU
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