Indoor Air Quality
Indoor Air Quality is the composition of the air inside the house: what is emitted into it, how much outdoor air replaces it, and what is filtered out of it. It matters in Central Texas because people here spend most of their hours indoors with the windows closed, and because a house tight enough to control humidity is also tight enough to hold whatever is released inside it. Ventilation has to be designed and its outdoor air conditioned, or the same measures that improve comfort can concentrate indoor-generated pollutants.
The order of operations
Source control, then ventilation, then filtration. Reversing that order costs more and works less well.
- [ESTABLISHED]Established
Removing or not specifying an emission source is more reliable than diluting or filtering it afterward.
- [ESTABLISHED]Established
Mechanical outdoor-air ventilation is required in tight houses; a whole-house rate is designed, installed, and commissioned rather than left to infiltration.
- [ESTABLISHED]Established
Higher-efficiency particulate filtration reduces airborne particle concentrations when the equipment is sized to carry the pressure drop.
Combustion
We prefer to keep combustion appliances out of the conditioned envelope, and where a gas cooking appliance is used we specify a ducted, exterior-venting range hood with a measured capture strategy.
Garages
Attached garages are treated as a pollutant source and air-sealed from the living space as a matter of course.
What gets measured
- [ESTABLISHED]Established
We record ventilation airflow at commissioning, filtration level installed, and any indoor readings taken, each with instrument and date.
- [EMERGING]Emerging
Interpretation of low-cost consumer air-sensor data is limited; we use such readings as directional signals and say so when we do.
Sources
Primary references for this page. Where a statement is graded Emerging, the source supports the question being open, not a conclusion.
- 1. Indoor Air Quality (IAQ) — U.S. Environmental Protection Agency
- 2. Volatile Organic Compounds' Impact on Indoor Air Quality — U.S. Environmental Protection Agency
- 3. ASHRAE Standard 62.2 — Ventilation and Acceptable Indoor Air Quality in Residential Buildings — ASHRAE
Related reading
Sources we read and work from under this domain. Pointers to the document, not reports of a finding.
- Building scienceUnderstanding Ventilation in Hot-Humid ClimatesJoseph Lstiburek, 2006 · Building Science Corporation
- GuidanceLBNL Indoor Environment Group — IAQ ScienceLawrence Berkeley National Laboratory · Lawrence Berkeley National Laboratory
- GuidanceNIST Indoor Air Quality and Ventilation GroupNational Institute of Standards and Technology · NIST
- StandardANSI/ASHRAE Standard 62.2 — Ventilation and Acceptable Indoor Air Quality in Residential BuildingsASHRAE, 2022 · ASHRAE
- StandardANSI/ASHRAE Standard 241 — Control of Infectious AerosolsASHRAE, 2023 · ASHRAE
- GuidanceEPA Indoor airPLUS Construction SpecificationsU.S. Environmental Protection Agency, 2025 · U.S. EPA
Last reviewed August 29, 2026. Reviewed and maintained by Sage Co.
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