Indoor Air Quality Proposal: Filters, UV, Humidity

The homeowner points to one line on the estimate:

Whole-home indoor air quality package: media filter, UV light, and humidifier.

The contractor means three pieces of equipment.

The homeowner hears cleaner air, fewer allergies, no winter dryness, no mold, and fewer illnesses.

That gap is where an indoor air quality proposal goes bad.

A useful proposal does not begin with a bundle. It begins with the customer's stated problem, the conditions the technician actually observed, and the job each proposed measure is supposed to do. It then names what the system cannot establish or promise.

Use an HVAC inspection report for the existing conditions and readings. Present the selected measures and alternatives in an HVAC proposal. Put quantities and prices in the HVAC quote, carry accepted work into the HVAC work order, and record startup results in the HVAC service report.

That paperwork sequence keeps “better air” from becoming an unlimited warranty.

Start with the complaint, not the accessory

“Customer wants IAQ” is not enough information to design or price a job.

Ask what started the call:

• smoke or outdoor-pollution concerns;
• visible dust or rapid filter loading;
• an odor in one room or at certain times;
• dry-air discomfort during heating season;
• window condensation or high indoor humidity;
• a renovation, new furniture, pets, cooking, hobbies, or another indoor source;
• a request from a physician, employer, school, insurer, or property manager;
• concern about airborne infection in a shared space;
• a sales offer the customer saw for a filter, UV device, ionizer, purifier, or humidifier.

Record the concern as the customer described it. Do not turn a report of symptoms into a diagnosis, and do not collect more medical detail than the job requires.

The U.S. EPA's current IAQ guidance organizes indoor-air improvements around three strategies: control the source, improve ventilation, and supplement those measures with filtration or air cleaning. That order matters. A filter cannot repair a roof leak, a UV lamp cannot remove a combustion source, and a humidifier cannot correct an oversized cooling system that leaves a house damp in summer.

A strong intake row looks like this:

This gives the technician a bounded assignment. It does not promise a result before the system and building are inspected.

Separate four different jobs

Filters, UV equipment, humidifiers, and ventilation do not solve the same problem.

The customer may need one of those jobs, several of them, or a source-control repair outside the HVAC scope.

Do not force every concern into a three-product package. If the inspection shows a wet crawlspace, disconnected bath fan, return leak beside a dusty attic, or an unvented pollutant source, write the finding and the correct handoff. Selling an accessory without naming the source leaves the customer with the same problem and a more expensive system.

Inspect the system before promising filter efficiency

EPA recommends a furnace or HVAC filter rated at least MERV 13, or the highest efficiency the system can accommodate. The important half of that sentence is system compatibility. EPA's Guide to Air Cleaners in the Home notes that the fan and filter slot must be able to handle the selected filter and that filtration occurs only while air moves through the system.

Before quoting an upgrade, record:

The HVAC filter change-log workflow explains why size, quantity, rating, condition, and rack fit belong in the permanent service record. An IAQ proposal adds the upgrade decision: what the present system can support, what must be modified, and how the shop will verify operation afterward.

Do not write:

Install MERV 13 filter for healthier air.

Write:

Install listed 4-inch media cabinet and specified MERV 13 replacement media on return side of System 1. Scope includes transition fabrication, accessible joint sealing at new cabinet, filter label and airflow-direction marking, initial clean filter, and pre-/post-installation airside readings listed below. Final approval is subject to confirming cabinet clearance and acceptable system operation in cooling and fan-only modes. This measure filters recirculated air while the blower operates; it does not add outdoor air or remove every particle, gas, odor, or pollutant source.

That sentence identifies equipment, location, included labor, verification, and the performance boundary.

Build commissioning into the filter scope

A filter proposal should define more than a MERV number.

Include:

• manufacturer and model or an approved-equal rule;
• nominal size, actual fit, depth, quantity, and rating;
• published initial resistance or the product data the selection relied on;
• cabinet, transition, gasketing, and access work;
• any blower or control adjustment included;
• the operating modes to be checked;
• the readings to be captured before and after installation;
• the replacement-media part number;
• the initial inspection or replacement interval;
• who supplies future filters and what they are expected to cost under the current quote;
• what happens if the system cannot operate acceptably with the proposed selection.

EPA's June 2026 Indoor Air Filtration fact sheet, written for wildfire-smoke preparation, tells consumers to choose MERV 13 or higher and consult the HVAC technician or manufacturer about the highest-efficiency filter that will work with the system. It also emphasizes snug fit, operating time, and checking the filter when it becomes dirty or develops an odor.

Those are proposal facts, not afterthoughts.

For example:

If final readings show that the selected media, cabinet installation, or programmed fan operation places the system outside the equipment manufacturer's allowed operating range, the shop will stop commissioning and present a written correction option. No substitute filter rating, blower modification, duct alteration, or equipment replacement is authorized unless added in writing.

If the customer approves a different cabinet, added return work, or a blower correction after the proposal is accepted, use a change order. Do not hide the difference inside “miscellaneous IAQ labor.”

State whether the UV light treats a coil or moving air

“Install UV light” is not a complete scope.

There are at least two different assignments:

1. Surface treatment: the device is selected and positioned to irradiate a defined coil, drain-pan, or nearby surface under stated conditions.
2. Airstream treatment: the system is selected and designed to deliver a suitable dose to moving air under the actual airflow, temperature, humidity, geometry, reflectivity, and target-organism assumptions.

Those assignments are not interchangeable.

NIOSH's guidance for upper-room GUV describes that occupied-space application as a supplemental intervention, not a replacement for code-required outdoor air or filtration. It also stresses qualified design, installation, testing, training, controlled switching, and safe maintenance because UV energy can injure eyes and skin. Those statements do not size an in-duct or coil device; those applications still require the exact product instructions and any application-specific engineering or specialist design the job requires.

For an in-duct or coil application, the proposal should identify:

ASHRAE's UV-C application discussion explains why airstream work has no one-size-fits-all dose: airflow volume and velocity, temperature, humidity, duct reflectivity, and other conditions affect the selection. A bench result or a manufacturer's single-pass percentage does not automatically describe performance in the customer's installed system.

Avoid this:

UV purifier kills 99.9% of viruses and mold throughout the home.

Use this kind of boundary:

Install the specified UV-C device for coil-surface treatment at the indoor unit location shown in the attached photo. Selection and placement follow the current manufacturer application instructions for this coil geometry. The work includes the listed power connection, warning label, service shutoff, operating indicator check, owner training, and replacement schedule. This is supplemental HVAC equipment; it is not represented as sterilizing rooms, treating occupants, removing an existing mold source, or replacing ventilation, filtration, cleaning, or medical advice.

That is still a sellable scope. It is also one the shop can inspect at closeout.

Put ozone and electronic-air-cleaner claims on the product checklist

“Electronic air cleaner” can describe very different technologies.

Before proposing ionization, electrostatic collection, plasma, photocatalytic treatment, or another powered air-treatment device, collect the exact product data and determine which claims and rules apply where it will be sold and installed.

EPA's guidance on ozone-generating air cleaners says no federal agency has approved these devices for use in occupied spaces and warns that an EPA establishment number does not mean EPA approved the device as safe or effective. The proposal should never use an establishment number, a generic “EPA” logo, or a vague registration reference as an endorsement.

California adds a specific sales boundary. Its indoor air-cleaner regulation requires covered devices sold in the state, including electronic in-duct air cleaners, to be CARB-certified and labeled. A certification submission includes the applicable electrical-safety documentation, and electronic air cleaners must also meet the ozone-emission requirements. Mechanical-filtration-only devices and qualifying portable UVGI-only devices are exempt from ozone-emission testing, not from the certification framework. CARB certification addresses that regulatory boundary; it does not by itself prove the contractor's broader performance or health claim.

Keep a product submittal in the job file showing:

• exact model and technology;
• intended application and occupied-space status;
• electrical listing and installation instructions;
• ozone-emission certification or exemption documentation where applicable;
• replacement parts and service life;
• the manufacturer's exact performance claim and test conditions;
• any state restriction, label, or sales limitation;
• what the contractor is and is not repeating in the proposal.

If the office cannot explain what the device produces, how it was tested, and which claim belongs to that exact model, do not fill the gap with “purifies the air.”

Humidity needs a range, a season, and a condensation stop point

A whole-home humidifier proposal should not promise “set it to 50% and forget it.”

EPA's home humidifier guidance says not to humidify above 50% relative humidity, to reduce output if condensation appears, and to follow manufacturer cleaning and maintenance instructions. EPA's broader home IAQ guidance describes below 60%, ideally 30–50%, as a general moisture-control range. Those are useful boundaries, but they are not a guarantee that every building can safely hold the same setpoint.

Outdoor temperature, insulation, windows, air leakage, thermal bridges, occupant activity, equipment type, and sensor location can all change where condensation appears. The proposal should therefore define the control approach and the owner's response when the building says the setting is too high.

Record:

EPA also notes that standing water and poorly maintained humidifiers can support microorganisms. A proposal that sells moisture but omits cleaning, drainage, seasonal shutdown, and consumables is incomplete.

Use language like this:

Install the listed whole-home humidifier to serve System 1 during heating operation. Initial control setting will be established at commissioning under the conditions present that day and is not a year-round guaranteed humidity level. Owner must reduce the setting or stop humidifier operation if condensation appears on windows, walls, ducts, or other surfaces and request service if the condition persists. Cleaning, water-panel or canister replacement, drain inspection, and seasonal startup/shutdown will follow the listed manufacturer intervals and are maintenance items unless included in the attached service plan.

That tells the customer how the equipment will be controlled and where responsibility changes after handoff.

Do not make “good, better, best” mean “more gadgets”

Tiered proposals work when each option has a clear objective. They fail when every higher tier simply adds another accessory.

A better option table might look like this:

If the building needs ventilation design, source removal, envelope repair, professional sampling, or another specialist, show that as a prerequisite or separate alternate. Do not bury it as an exclusion after pricing a package that depends on it.

The Manual J load-report guide makes the same point in a different HVAC decision: a documented input and method are more defensible than copying an old equipment label. IAQ proposals also need an observed condition and selection basis, not a familiar accessory bundle.

Write the exclusions next to the promise

An IAQ proposal needs more than a generic sentence saying “no guarantees.” The specific boundary should sit beside the specific measure.

Common exclusions to confirm are:

• medical diagnosis, treatment, symptom relief, allergy prevention, or infection prevention;
• a guarantee that a building, room, surface, or duct system is sterile, allergen-free, mold-free, smoke-free, odor-free, or pollutant-free;
• environmental sampling, laboratory analysis, industrial hygiene, or interpretation of test results unless a qualified party and exact scope are named;
• asbestos, lead, radon, mold, pest, hazardous-material, combustion, or soil-gas investigation and remediation;
• repair of roof, plumbing, foundation, crawlspace, envelope, drainage, or other moisture sources;
• ventilation, exhaust, balancing, duct cleaning, duct sealing, or building-pressure work not itemized;
• concealed electrical, plumbing, drain, framing, firestopping, access, finish, or code-correction work;
• permits, engineering, design by others, or trade work not specifically included;
• portable air cleaners or rooms outside the identified system and area served;
• customer-supplied equipment or media unless acceptance and warranty terms are written;
• filters, lamps, pads, canisters, cleaning, water treatment, and other recurring consumables after the included period;
• changes in occupancy, pollutant sources, outdoor conditions, building operation, or maintenance after commissioning.

Do not use exclusions to contradict the headline. The FTC's Health Products Compliance Guidance says marketers need adequate substantiation for objective health-related claims and evaluates the overall message, including implied claims. A small disclaimer cannot repair a proposal that repeatedly says the product will prevent illness, eliminate allergies, or make occupants healthy.

The safer sales rule is simple: sell the documented equipment function and installation outcome. Do not sell a medical outcome the shop has not established.

Make maintenance part of the first price conversation

The customer should see the recurring obligation before signing.

For each proposed measure, list:

The existing commercial filter-log guide is useful even on residential jobs because it ties the installed filter to an asset, date, condition, replacement, and recommendation. The same approach works for lamps, pads, and controls.

If the shop offers a maintenance agreement, define whether consumables are included, whether after-hours calls are covered, and whether missed owner maintenance affects the shop's labor warranty. Keep manufacturer requirements attached to the exact product instead of paraphrasing them from memory.

The manufacturer warranty pass-through guide shows how to separate the product maker's promise from the contractor's labor, access, diagnostic, shipping, and maintenance obligations. An IAQ proposal should make that split before the first lamp or media cartridge needs replacement.

Turn the accepted scope into a commissioning and handoff record

The proposal says what will be installed. The service report proves what happened.

At closeout, record the applicable items:

• proposal, work-order, and change-order numbers;
• equipment served and installed accessory model/serial numbers;
• filter cabinet, filter model, rating, size, direction, fit, and date installed;
• operating mode and pre-/post-installation readings;
• blower or control changes and final settings;
• UV application, location, warning label, shutoff/interlock, indicator status, and safe-service instruction;
• humidifier model, control, initial setting, water and drain check, leak check, and condensation instruction;
• electrical, duct, drain, access, and finish work completed or left open;
• photos of labels, installation, readings, and exceptions;
• owner training topics, manuals, consumable part numbers, and next maintenance date;
• unresolved condition, referral, or declined recommendation;
• who accepted the handoff and when.

The mini-split startup-report workflow is a good model for the handoff: identify the exact equipment, preserve readings and configuration, distinguish installer work from owner maintenance, and leave the customer with warranty and operating information. Use the completion sign-off only after the service report states the open items; a signature should not erase an exception.

For photos, follow a repeatable standard rather than taking one finished-equipment picture. The work-order photo guide explains how before, during, after, label, measurement, and exception images support a written record without replacing it.

Example proposal scope

Here is a compact example for a filter cabinet and humidifier. It is not a design for a real building; the job-specific equipment, readings, instructions, local rules, and qualified judgment still control.

Customer goal. Reduce recirculated airborne particles during seasonal smoke events and add controlled moisture during dry heating-season operation. Customer reports upstairs smoke odor and winter dryness. This proposal does not evaluate medical symptoms or promise a health outcome.

Existing condition. System 1 is a ducted forced-air heat pump serving the house. Existing return uses one 16x25x1 MERV 8 filter with visible edge bypass. Filter cabinet depth, return transition, blower settings, accessible duct condition, baseline readings, indoor relative humidity, and installation clearances are recorded in Inspection Report IR-108. No outdoor-air intake was identified in the accessible equipment area; whole-building ventilation was not measured or designed under this scope.

Filter work. Install the listed 4-inch media cabinet and MERV 13 media filter, fabricate the described return transition, seal accessible new joints, label filter size and airflow direction, and record final operation in cooling and fan-only modes. If final readings do not support acceptable operation under the equipment instructions, stop commissioning and provide a written correction option before changing the filter selection, blower, or duct system.

Humidifier work. Install the listed humidifier, control, sensor, water connection, shutoff, drain, duct fitting, and electrical connection shown in the scope attachment. Establish an initial heating-season setting during commissioning. Owner must reduce the setting or stop operation if condensation appears and request service if it persists. Manufacturer-specified cleaning, consumable replacement, drain inspection, and seasonal startup/shutdown are owner maintenance unless purchased separately.

Excluded. UV or electronic air treatment; portable cleaners; ventilation design; duct cleaning; concealed duct repair; mold, radon, asbestos, lead, combustion, or pollutant testing; source remediation; building-envelope or window repair; medical advice; and a guarantee that odors, symptoms, smoke, particles, microorganisms, or indoor humidity will remain at a particular level under all conditions.

Handoff. Provide installed model and serial information, product instructions, initial filter and consumable part numbers, final readings, controls demonstration, maintenance dates, photos, warranty split, and signed completion record.

Attach that narrative to a statement of work, not just the total on an estimate. The written-quote guide explains why scope, assumptions, exclusions, expiration, and approval should be preserved before work begins.

Sources

Sources below were checked July 22, 2026.

• U.S. EPA, Improving Indoor Air Quality, reviewed July 22, 2026, for the source-control, ventilation, and supplemental filtration hierarchy and the limits of air cleaning.
• U.S. EPA, Guide to Air Cleaners in the Home, reviewed July 22, 2026, for MERV 13-or-system-limit guidance, HVAC runtime, filter fit, particle/gas distinctions, and the statement that EPA does not certify or recommend particular brands.
• U.S. EPA, Indoor Air Filtration, EPA-452/F-26-006, June 2026, for wildfire-smoke filtration planning, system-compatibility review, snug filter fit, operating time, and replacement checks.
• U.S. EPA, Use and Care of Home Humidifiers, updated April 29, 2026, for humidity limits, condensation response, water and microorganism concerns, and central-humidifier cleaning and maintenance.
• U.S. EPA, What can I do to improve indoor air quality in my home?, updated June 4, 2026, reviewed July 22, 2026, for the general below-60%, ideally 30–50%, moisture-control range.
• NIOSH, About Germicidal Ultraviolet (GUV), October 4, 2024, reviewed July 22, 2026, for the upper-room application's supplemental-use, qualified-design, installation, training, maintenance, switching, and eye/skin safety boundaries.
• ASHRAE, Behind the Update: ASHRAE Handbook Chapters on UV-C, for the distinction among UV-C applications and the effects of airflow, velocity, temperature, humidity, reflectivity, geometry, dosing, commissioning, and maintenance.
• U.S. EPA, Ozone Generators that are Sold as Air Cleaners, reviewed July 22, 2026, for occupied-space, effectiveness, health, reaction-byproduct, and EPA-establishment-number cautions.
• California Air Resources Board, Regulation for Limiting Ozone Emissions from Air Cleaning Devices, 17 CCR §§ 94800–94808, reviewed July 22, 2026, for California certification, ozone-emission, testing, electrical-safety, labeling, and internet-sale requirements for covered devices.
• Federal Trade Commission, Health Products Compliance Guidance, December 2022, reviewed July 22, 2026, for express and implied claim analysis, substantiation, clear disclosures, testimonials, and the limits of contradictory disclaimers.
• The current installation, operation, maintenance, electrical-listing, performance-test, consumable, and warranty instructions for the exact filter, cabinet, UV, electronic air-cleaner, humidifier, control, HVAC equipment, and accessory selected, plus the adopted code, AHJ, state sales rule, licensed-trade, engineer, building-owner, insurer, and health-professional requirements that apply to the actual job.

This article is for general information and is not medical, legal, safety, code, engineering, industrial-hygiene, environmental-testing, licensing, warranty, or building-science advice. Verify the customer's actual system, source conditions, airflow, filter compatibility, UV application, humidity control, electrical and plumbing work, ventilation, product claims, ozone rules, permits, maintenance, and warranty with the manufacturer, AHJ, qualified HVAC professional, engineer, industrial hygienist, physician, attorney, insurer, or other appropriate specialist before acting.