Air, Ventilation, and Indoor Air Quality

Understand How Your Home Gets Fresh Air

Cooking, cleaning, bathing, furnishings, and building materials can all affect indoor air. A thoughtful renovation considers these sources alongside the ways air enters, moves through, and leaves your home.

Ventilation, exhaust, and filtration perform different jobs. Understanding those differences helps you ask better questions before choosing equipment or finalizing a design.

Three Different Jobs: Ventilation, Exhaust, and Filtration

Ventilation

exchanges indoor air with outdoor air.

Local exhaust

removes air near a source, such as a kitchen or bathroom, through an appropriate discharge route.

Filtration

captures certain airborne pollutants as air passes through a filter. Particle filters do not remove every type of pollutant.

Heating or cooling a room does not necessarily supply outdoor air. Ask how your proposed system handles each function.

What to Consider During Design

1. Reduce Pollutants at the Source

Review the materials and products introduced into the home, including cabinetry, paints, adhesives, finishes, and furnishings.

Consider the complete installation—not just the visible surface. Product selection, installation conditions, and everyday use all deserve attention.

Where relevant, ask your project team to review how attached garages, fuel-burning equipment, and other potential pollutant sources are separated from living spaces.

2. Plan Kitchen and Bathroom Exhaust Early

Discuss cooking exhaust and bathroom ventilation while layouts and system routes are still being developed.

Ask where the air goes, how the system will operate, and what constraints affect its installation. Fan noise, controls, access for maintenance, and the availability of replacement air should be part of the conversation.

3. Coordinate Ventilation With the Building

Air sealing, windows, ducts, and existing ventilation systems influence how air moves through a home.

When renovation work changes the building’s airtightness or systems, review the ventilation strategy at the same time. The appropriate solution depends on existing conditions, climate, outdoor air quality, and the scope of work.

4. Choose Filtration That Fits the System

Portable air cleaners and HVAC filters can help reduce airborne particles. Their usefulness depends on the pollutant, equipment, airflow, sizing, and maintenance.

Discuss compatible options with your project team rather than assuming a higher-rated filter will work with any system.

5. Address Moisture Alongside Air

Bathroom exhaust, cooking, leaks, condensation, and humid outdoor air can all influence indoor moisture.

Persistent dampness needs investigation of its source. Ventilation decisions should be coordinated with moisture management, heating, and cooling.

Planning Ventilation in NYC Homes

Apartments, Co-ops, and Condos

Begin by understanding the existing building systems and alteration requirements. Ask whether proposed work affects shared shafts, exhaust connections, exterior openings, or equipment serving other apartments.

Before selecting a range hood, bathroom fan, or ventilation unit, have your project team confirm the available routes and relevant building constraints.

Townhouses

A townhouse renovation may provide opportunities to coordinate ventilation with roof or façade work, insulation, windows, and mechanical upgrades.

Review the whole building—including cellar or basement conditions—and consider how changes on one floor may affect air movement elsewhere.

Questions to Ask Your Project Team

How is outdoor air currently supplied, and what will change?
How will cooking pollutants and bathroom moisture be captured and exhausted?
What building constraints affect the proposed approach?
How will air sealing and ventilation be coordinated?
Where will equipment and ducts fit, and how will noise and maintenance access be addressed?
What filtration is compatible with the equipment?
Are there pollutant sources or adjoining spaces that need particular attention?

Discuss these questions while layouts and system routes are still being developed, before walls and ceilings are closed.

You do not need to select the system yourself. These questions help establish what the design needs to resolve.

Common Questions

Does air conditioning bring in fresh air?

Not necessarily. Many residential heating and cooling systems recirculate indoor air without supplying outdoor air. Ask your project team to explain how ventilation is provided separately or integrated into the proposed system.

Can an air purifier replace ventilation?

A typical portable air purifier filters air within a room; it does not supply outdoor air or exhaust bathroom moisture. It can support an indoor-air strategy alongside source control and appropriate ventilation.

Is opening windows enough?

Opening windows can increase air exchange when weather and outdoor air quality allow. Its effectiveness varies with conditions and use, so it should not automatically be assumed to meet the home’s ventilation needs throughout the year.

Does every home need an ERV?

No. An energy recovery ventilator is one possible approach to mechanical ventilation. Its suitability depends on the building, climate, available space, installation routes, and coordination with other systems.

The starting point is to understand the home’s ventilation needs and constraints before choosing equipment.

Bring Air and Ventilation Into the Design Conversation

If you are planning a renovation, discuss air, exhaust, and comfort priorities before layouts and system routes are settled.

Tong Dong Architects considers these questions as part of the architectural design process, coordinating with appropriate consultants according to the project scope.

Start My Project

Still exploring? Build Without Regrets, our free renovation starter kit, includes planning guidance and questions to help you prepare.