Original data and independent reporting for the HVAC trade
The HVAC Brief: independent HVAC trade reporting and original data
Analysis & data
Newest first-
Low Water Cutoff: How Float and Probe LWCOs Work, Code Rules, Testing and Reset
A low water cutoff stops a boiler’s burner before it dry fires. How float and probe types work, where the IRC and state rules require one, maker test and blowdown…
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Smart Vents: What the Closed-Register Research Says, and When They Work
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Thermostatic Mixing Valve: How It Works, ASSE 1017 vs 1070 and What Code Requires
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Ducted Mini Split: Static Pressure Limits, Ratings and Duct Design Rules
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Electronic Air Cleaner: How It Works, Ozone, Cleaning and MERV
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Indirect Water Heater: How It Works, Sizing, Priority Zones and Federal Rules
Industry news
From the trade-
Heating Oil Forecast Up 35% This Winter; Gas Falls
EIA’s September outlook puts heating oil 35% above last winter and residential gas 9% below. At forecast prices, oil heat costs closer to electric resistance than to gas.
- Still allowed
R-410A equipment built before 2025 can still be installed
EPA’s final rule removed the installation cutoff for inventory manufactured or imported before January 1, 2025. New R-410A equipment cannot be built or imported. Several states are stricter. Full rule detail
- Expired
The federal 25C heat pump tax credit is gone
The credit, worth up to $2,000, applied to property placed in service before December 31, 2025. Installation date controls, not purchase date. State and utility rebates are unaffected. What this costs you
- Still rising
Equipment prices set another high in August
Producer prices for HVAC equipment are up 60% since 2019 against 31% for consumer prices. August 2026 is the highest reading in the series. See the index
Refrigerants
All refrigerants-
Nitrogen Pressure Test: PSI by Manufacturer, Hold Times and Temperature Correction
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Refrigerant Oil: POE vs Mineral, PVE, What R-410A Uses and When You Can Mix
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Schrader Valve on AC Systems: Cores, Caps, Port Sizes, Leaks and Locking Cap Code
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Filter Drier: What It Does, Liquid Line vs Bi-Flow, and When to Replace It
Equipment
All equipment
Codes & Standards
All codes & standards-
Fire Damper: Where Code Requires Them, Fusible Links and the Inspection Clock
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Cooling Tower: How It Works, Range and Approach, Water Use and Legionella Rules
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Make Up Air: When Code Requires It, Combustion Air, Dampers and the Pressure Math
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Refrigerant Recovery: EPA Vacuum Levels, Machines, Cylinders and the AIM Act Rules
