Manual J calculator · TX
Manual J load calculation for Texas.
Run an ACCA Manual J 8th Edition residential load calculation with climate context pre-loaded for Texas — ASHRAE design temperatures for 5 top metros, IECC 2015, and TDLR licensing context already accounted for in the assumption defaults.
Pre-loaded scenario
Houston, TX (Harris County) · ASHRAE zone 2A · winter 99% DB 34°F · summer 0.4% DB 96°F · MCWB 77°F.
ASHRAE 169-2021 · ACCA MJ8 §6
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01 · ASHRAE design conditions
Top 5 metros in Texas — design temperatures used in Manual J.
These are the ASHRAE 99% heating and 0.4% cooling design temperatures — the values Manual J uses for the design day, not the absolute extremes. Equipment sized to these conditions undersizes for ~35 hours per year in summer (acceptable per ACCA convention) and ~22 hours per year in winter.
| Metro | County | Zone | Winter 99% DB | Summer 0.4% DB | MCWB |
|---|---|---|---|---|---|
| Houston | Harris County | 2A | 34°F | 96°F | 77°F |
| Dallas–Fort Worth | Dallas / Tarrant County | 3A | 24°F | 100°F | 75°F |
| San Antonio | Bexar County | 2A | 31°F | 98°F | 74°F |
| Austin | Travis County | 2A | 30°F | 99°F | 74°F |
| El Paso | El Paso County | 3B | 25°F | 100°F | 64°F |
Source: ASHRAE 169-2021 (republished in EERE Building America Guide 7.3, public domain). DB = dry-bulb. MCWB = mean coincident wet-bulb at the 0.4% cooling design hour.
02 · Energy code
Texas energy code: IECC 2015
Adopted 2016. Manual J load-calc documentation requirements flow from the state energy code; verify your specific AHJ’s submittal rules before relying on the baseline.
- Texas SECO has not adopted IECC 2018 or 2021 statewide — IECC 2015 remains the baseline for residential construction outside home-rule jurisdictions.
- Home-rule cities (Austin, Dallas, Houston, San Antonio) may amend up to a newer IECC edition; verify with local AHJ before relying on this baseline.
Source: SECO — State Energy Code adoption (Texas) · verified 2024-12-15
03 · Texas HVAC labor data
BLS wages and employment for HVAC mechanics in Texas.
These are state-level wages for occupation code 49-9021 — Heating, Air Conditioning, and Refrigeration Mechanics and Installers — from the most recent BLS Occupational Employment and Wage Statistics release.
- Median hourly wage
- $25.36
- Mean annual wage
- $53,810
- Employment estimate
- 34,350
Source: BLS OEWS May 2023, SOC 49-9021 (state-level) · released 2024-04-03. Loaded labor rates billed to customers typically run 2.5–3.5× the technician wage after overhead.
04 · License & permit
HVAC licensing in Texas: TDLR.
State-level HVAC contractor licensing is administered by the Texas Department of Licensing and Regulation. Licenses renew annually, with 4 hours of continuing education per cycle.
License types
- Class A Air Conditioning & Refrigeration Contractor (unlimited tonnage)
- Class B Air Conditioning & Refrigeration Contractor (≤25 tons cooling, ≤1.5M BTU heating)
- Technician Registration
Permits
Most Texas AHJs require a mechanical permit for new HVAC installations, system replacements that change capacity, and ductwork modifications. Permits are issued by city building departments; unincorporated areas typically defer to county.
Replacement permit: typically required.
Texas has no single statewide permit portal — check the city or county building department for the specific job site.
05 · FAQ
Common Manual J questions for Texas contractors.
+Can I use BuildSolver for a Manual J in Texas without a TDLR license?
Yes — BuildSolver is a sizing aid for contractors and homeowners alike. Whether the calculation can be submitted for permit is a separate question and depends on the local AHJ. Most Texas jurisdictions require a TDLR-licensed contractor to pull the permit; the load calc itself can be performed by anyone competent to apply ACCA Manual J.
+Which ASHRAE climate zones cover Texas?
Texas spans five zones — 2A (Houston, Gulf Coast), 2B (parts of West Texas), 3A (Dallas–Fort Worth, Austin metro), 3B (El Paso, Lubbock), and 4B (Panhandle high plains). Always confirm your county's zone before applying default infiltration or window U-factor assumptions.
+Does Texas require IECC 2021 yet?
No. The State Energy Conservation Office (SECO) has kept IECC 2015 as the residential baseline. Home-rule cities such as Austin or Dallas may have adopted newer editions with local amendments — verify with the city's energy code amendment list before assuming the statewide baseline applies.
+How much does a Texas HVAC technician charge per hour on average?
BLS OEWS May 2023 reports a median wage of $25.36/hr for HVAC mechanics and installers in Texas — translating to about $53,810/year on average. Loaded labor rates billed to customers typically run 2.5–3.5× the technician wage after overhead, vehicle, insurance, and benefits. TDLR-licensed Class A/B ACR contractors must complete 4 hours of continuing education annually per TAC §75.65.
+How does Houston's design temp affect Manual J sizing?
Houston's ASHRAE 0.4% summer DB is 96°F with a 77°F mean coincident wet-bulb — high latent load. Sensible-only sizing typically under-equips dehumidification capacity by 15–20% in zone 2A. BuildSolver runs both sensible and latent at the ACCA Manual J 8th-edition split (§6 and §8) so the latent share shows in the output.
+Can BuildSolver substitute for a stamped Manual J on a Texas permit?
No. Texas AHJs that require a stamped or ACCA-approved Manual J for permit submittal will not accept a BuildSolver output. Use BuildSolver for sales-phase sizing and client quotes; use Wrightsoft or Cool Calc for the stamped permit submittal.
Try a Texas load calculation now.
The chat will ask follow-up questions like an experienced engineer — square footage, construction type, window count, insulation level — and run the Manual J on your inputs with Texas’s ASHRAE design temperatures applied automatically. About 90 seconds end to end.
Start Texas calculationRelated · same climate zone
Other states with similar ASHRAE climate zones.
Manual J assumptions for infiltration, latent share, and design temperatures behave similarly across states that share an ASHRAE zone. The pages below carry the same procedural defaults with their own local design temps and licensing context.
Data last reviewed 2026-05-19 · underlying sources as of 2024-04-03