Somebody in the house reacts and nobody knows why
Symptoms that improve when the person leaves the building and return when they come back are the classic pattern worth measuring.
Measurement instead of guessing
Indoor Air Quality Testing in Aledo, TX
- Logged over days, not sampled once
- Written report with findings
- Remedies named specifically
- No equipment sold on the strength of it
Air quality complaints are usually described rather than measured. Somebody in the house is reacting to something, the air feels stale in certain rooms, or there is a smell nobody can place, and the conversation that follows is mostly speculation.
Instruments replace that speculation with numbers. Particle concentration, carbon dioxide as a proxy for ventilation, relative humidity, temperature stratification and volatile organic compounds, logged across days rather than sampled once, produce a picture that actually points somewhere.
What gets measured and why
01 02 03 04 05 06 07 08
Testing is only useful if it measures the things that have plausible remedies. The parameters below are chosen because each one, if it comes back poor, points at specific work rather than at a vague recommendation to improve the air.
Logging over time matters as much as the parameters themselves. Occupancy, cooking, showering, the heating system cycling and outdoor conditions all move these numbers, and a pattern across several days tells you far more than any single sample.
The parameters and what each one reveals
Particulate concentration, measured at fine and very fine size fractions, reflects what is actually suspended in the air people are breathing. Indoor sources include cooking, candles, smoking and resuspended dust, while outdoor sources arrive through the envelope and through ventilation. Logging it shows whether spikes follow activities inside the house or conditions outside it, and those two findings lead to completely different remedies.
Carbon dioxide is measured not because it is harmful at the levels found in homes, but because it is an excellent proxy for ventilation. People exhale it continuously, so if concentration climbs steadily through the night in a bedroom and falls when the door opens, that room is under ventilated. It is the single most useful measurement for diagnosing stale air complaints.
Relative humidity is logged because both extremes cause problems. Too high and you get condensation, mold growth, dust mites and a house that feels warmer than it is. Too low and you get static, respiratory irritation, cracking timber and a house that feels colder than it is. Humidity also interacts directly with the cooling system, since a short cycling oversized unit leaves moisture behind.
Volatile organic compounds are logged as a total rather than speciated, which is honest about what the instrument can tell you. A high total after new furnishings, flooring or paint points at off gassing and at ventilation as the remedy. Persistent elevation with no obvious source is a finding that warrants a specialist laboratory rather than a pretence of precision this equipment does not have.
Ventilation, the parameter behind most complaints
Modern construction is considerably tighter than older housing stock, and tightness is desirable for energy performance. What it removes is the accidental ventilation that leaky buildings provided without anybody planning it.
In a tight building without mechanical ventilation, indoor pollutants accumulate because nothing is removing them. The household experiences that as stale air, lingering cooking smells, condensation on windows in winter and a general sense that the house does not feel fresh. Carbon dioxide logging demonstrates it unambiguously.
The remedy is controlled mechanical ventilation rather than opening windows in January. Energy and heat recovery ventilators exchange indoor and outdoor air while recovering most of the heat, or the cooling, from the air being expelled. Sizing and duct routing for those is a design exercise of its own.
Exhaust also matters and is frequently inadequate. Bathroom fans that were never connected properly, that terminate in an attic rather than outdoors, or that are too weak for the space are extremely common. So are range hoods that recirculate through a filter rather than venting outside, which does nothing at all for moisture or combustion products.
What the report contains, and what it deliberately does not
Findings are presented as logged data with the periods and conditions noted, alongside the reference ranges those readings are being compared against. Where a parameter is fine, the report says so plainly rather than finding something to worry about.
Each poor finding is paired with the specific remedy it points to. High carbon dioxide overnight in bedrooms points at ventilation and at transfer air. High particulates tracking cooking points at range hood capture and exhaust. High humidity in cooling season points at equipment sizing and run time. Low humidity in heating season points at humidification and possibly at envelope air leakage. Musty odor when the system runs points at the duct system and at moisture in a crawl space or return path.
What the report does not do is recommend a product on the strength of a reading that does not support it. Air quality is a field with a great deal of equipment sold on fear, and a testing service whose findings always happen to justify the equipment the same company sells is not a testing service. Where the data shows a building is adequately ventilated and reasonably clean, that is the report you get.
Mold and asbestos are named explicitly as outside this scope. Both require accredited laboratory analysis and, for asbestos, licensed abatement. Where something during testing suggests either, you are told and referred rather than sold an approximation.
Parameters logged and what a poor result points to
| Parameter | Why it is measured | Remedy a poor reading points to |
|---|---|---|
| Fine particulates | What occupants actually breathe | Filtration, source control, range hood capture |
| Carbon dioxide | A reliable proxy for ventilation rate | Mechanical ventilation and transfer air paths |
| Relative humidity | Comfort, mold risk, respiratory effect | Equipment sizing, humidification or dehumidification |
| Total volatile organics | Off gassing and chemical sources | Ventilation, source removal, or laboratory referral |
| Temperature stratification | Distribution and comfort | Airflow balancing and return placement |
| Exhaust airflow at fans | Whether extraction actually works | Fan replacement or correcting the duct termination |
How testing is carried out
01
Establish the complaint precisely
Which rooms, which times of day, which people and which seasons. The pattern shapes where instruments are placed.
02
Place logging instruments
Multiple locations including the rooms of concern and a reference point, left in place across several days of normal occupancy.
03
Inspect the mechanical systems
Filtration, the duct system, exhaust fans and their terminations, and any existing ventilation equipment.
04
Measure exhaust and ventilation
Actual airflow at bathroom and kitchen extraction, since a fan that runs is not necessarily a fan that works.
05
Report with findings and remedies
Logged data, reference ranges, specific remedies for each poor finding, and a plain statement where a parameter is fine.
When testing is worth doing
Condensation on windows through the winter
A clear indicator of high indoor humidity combined with insufficient ventilation, and a precursor to mold growth if left.
Stale air in particular rooms
Usually a ventilation and transfer air problem, and carbon dioxide logging demonstrates it precisely rather than arguing about it.
Smells that linger far longer than they should
Cooking odors persisting for hours generally means extraction is inadequate or terminating somewhere other than outdoors.
After renovation, new flooring or new furnishings
Off gassing is real and usually temporary, and measurement establishes whether it is subsiding on the expected trajectory.
A new tight building that feels stuffy
Modern construction removes the accidental ventilation older buildings had. Tight envelopes need designed ventilation rather than luck.
Before spending money on air cleaning equipment
Buying filtration for a problem that is actually ventilation, or humidity, wastes the money and leaves the complaint in place.
A basement or crawl space that smells musty
Air moves from those spaces into the living area far more than people expect, particularly where the return path passes through them.
Air quality questions
What Testing Can and Cannot Establish
This is a field with a lot of equipment sold on anxiety, so it is worth being precise about what measurement actually delivers.
Not in the sense that matters. Identifying mold species and concentration requires accredited laboratory analysis of collected samples, and interpreting the results properly is a specialist discipline. What this testing does contribute is the conditions that allow mold to grow: sustained high humidity, cold surfaces where condensation forms, and inadequate ventilation in bathrooms. Where visible growth or a persistent musty odor is found, you are told and referred to an accredited assessor rather than given an approximation.
Instruments are placed for several days of normal occupancy, because that is what produces a usable picture. A single afternoon reading tells you what was happening that afternoon, which is rarely the question. Placement and the mechanical inspection take a couple of hours, the logging runs unattended, and collection plus the report follows. You are asked to live normally during the period rather than ventilating unusually, because normal is what needs measuring.
Only if the data supports one, and frequently it does not. Portable purifiers are effective against particulates in the room they occupy and do nothing for ventilation, humidity or gases. If carbon dioxide logging shows a bedroom is under ventilated, a purifier will not change that reading at all. Recommending the remedy that matches the finding sometimes means recommending nothing at all beyond a better filter, and that is a legitimate outcome.
In heating season, somewhere in the range that avoids both static and condensation, which in practice means keeping it low enough that windows and cold surfaces stay dry. In cooling season, low enough that the house feels comfortable at a reasonable temperature rather than clammy. The precise target depends on your building, because a house with poorly insulated windows will form condensation at a humidity another house handles easily. The report gives a target for your building rather than a generic figure.
Not at the levels homes reach, and that is not why it is measured. It is measured because people produce it continuously and it therefore tracks ventilation almost perfectly. A bedroom where concentration climbs all night and drops when the door opens has demonstrated its ventilation rate without needing any other instrument. The concern is the other pollutants accumulating alongside it, which are harder and more expensive to measure directly.
Windows work and cost nothing, and in mild weather they are a perfectly good answer. The difficulty is winter and summer, when opening windows means paying to condition outdoor air that immediately leaves again, so households stop doing it exactly when the building is most closed up. A heat or energy recovery ventilator exchanges the air continuously while recovering most of the energy. Whether that is warranted depends on how tight your building actually is, which the testing establishes.
It can point strongly in that direction, and the mechanical inspection carried out alongside the logging is what confirms it. The signatures are recognizable: particulate levels that rise when the system cycles rather than when people cook, insulation fibers or a crawl space odor at the registers, and dust returning far faster than occupancy would explain. Those findings point at return side leakage rather than at filtration, and buying an air cleaner for that problem would leave it entirely in place.
Also in the catalog
What Testing Commonly Leads To
The value of measurement is that it points at one remedy rather than several.
Data before purchases
Get the Air Measured Before Anybody Recommends Equipment
Logged data across several days separates a ventilation problem from a filtration problem from a humidity problem. Those need different work.
Where the readings are fine, the report says so. Nothing is sold on the strength of a finding that does not support it.
- Particulates, carbon dioxide, humidity and organics logged over days
- Exhaust airflow measured at each fan rather than assumed
- Duct system and filtration inspected as part of the same visit
- A written report with each finding paired to a specific remedy
- Mold and asbestos referred to accredited specialists
- Flat rate quoted before the instruments are placed