# DOAS System Toronto | Rooftop Units Toronto Pros

> DOAS system Toronto: dedicated outdoor air install and service with energy recovery for IAQ upgrades. Red Seal crew. 24-hour written quote. Rebate filed.

URL: https://rooftopunitstoronto.ca/doas-system-toronto/

![Dedicated outdoor air system unit with energy recovery on a Toronto office roof](/images/misc/dedicated-outdoor-air-system-unit-with-energy-reco.webp)

Energy Recovery + IAQ

# Dedicated Outdoor Air Systems for Toronto Offices, Clinics and Schools

Last updated: October 24, 2026

DOAS install and service with energy recovery for ventilation and IAQ upgrades.

-   Stuffy rooms
-   High CO2 readings
-   Humidity swings
-   Tenant IAQ complaints
-   Ventilation below code

Book a Site Assessment

[/contact/ →](/contact/)

 

View Pricing

[#pricing →](#pricing)

24-Hour Written Quote

Written per-site quote

-   Parts, labour, crane, permit + HST on one line
-   2-4 hr on-roof emergency response, GTA core
-   Save on Energy rebate filed on qualifying work

Red Seal HVAC-RTSSA G1 + G2ESA + CRE$5M + WSIB

24/7 Dispatch (437) TBD

[tel:+14370000000 →](tel:+14370000000)

-   24-Hour Written Quote (not a sales pitch)
-   24/7 Emergency RTU Dispatch (2-4 hr on-roof GTA core)
-   Red Seal HVAC-R + TSSA + ESA + CRE Chiller
-   $5M Liability + WSIB + COI in 24 Hours
-   Save on Energy Rebate Filed on Your Behalf

1,800+

GTA installs

97%

Uptime

2-4 hr

On-roof, GTA core

48

Sites under contract

Symptoms first

## Is Your Equipment Showing These Signs?

Stuffy rooms, CO2 complaints, humidity swings or a ventilation upgrade for tenant IAQ requirements: we install and service DOAS units with energy recovery, paired with existing RTUs.

-   Stuffy rooms
-   High CO2 readings
-   Humidity swings
-   Tenant IAQ complaints
-   Ventilation below code

Seeing one of these? 

Book a site assessment

[/contact/ →](/contact/)

 or call dispatch for a 2-4 hour on-roof visit in the GTA core.

## When a Building Needs More Fresh Air

DOAS projects usually start with complaints: meeting rooms that feel stuffy by 2pm, **CO2** readings above target, humidity that swings with the weather, or a tenant whose lease requires better indoor air quality. Sometimes the trigger is a fit-out that adds occupants beyond what the original ventilation was designed for.

A **dedicated outdoor air system** (DOAS) brings in fresh outdoor air, filters it, conditions it and delivers it to occupied spaces, separately from the 

rooftop units

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 that handle heating and cooling.

## DOAS vs Make-Up Air Unit?

|  | DOAS | Make-up air unit |
| --- | --- | --- |
| Purpose | Ventilation for people | Replace air exhausted by hoods or garages |
| Conditioning | Heating, cooling, dehumidification | Usually heating only |
| Energy recovery | Common | Rare |
| Typical buildings | Offices, clinics, schools | Restaurants, commissaries, garages |

Kitchens and garages need a 

make-up air unit

[/make-up-air-unit-toronto/ →](/make-up-air-unit-toronto/)

. Offices, clinics and schools with IAQ needs usually need a DOAS.

## Does a DOAS Replace My RTU?

No. Your RTUs keep doing heating and cooling. The DOAS takes over ventilation, which often helps the RTUs: they no longer have to cool or heat large volumes of raw outdoor air through their economizers. Many buildings add a DOAS rather than oversizing RTU replacements.

## What Does Energy Recovery Save?

An **energy recovery wheel** or plate core (**ERV**) transfers heat, and with wheels moisture, between exhaust air and incoming fresh air. In a Toronto January, that means incoming air arrives much warmer than outdoors; in a humid July, it arrives drier and cooler. The DOAS and RTUs both work less.

## Sizing and Controls

We size outdoor air to **ASHRAE 62.1** for your occupancy, then add **CO2 demand control** so ventilation drops when rooms empty. Filtration up to **MERV 13** suits clinics and offices with IAQ requirements.

## Cost and Incentives

DOAS projects are quoted per site because airflow, recovery type and controls vary. You get a written quote within 24 hours of the site assessment. Energy recovery and high-efficiency equipment can qualify for incentives; see 

Save on Energy retrofits

[/save-on-energy-retrofit-toronto/ →](/save-on-energy-retrofit-toronto/)

. We install DOAS units for office parks in 

Markham

[/service-areas/markham/ →](/service-areas/markham/)

, clinics in North York and schools across the GTA, often alongside a 

new RTU installation

[/commercial-rooftop-unit-installation-toronto/ →](/commercial-rooftop-unit-installation-toronto/)

.

Published pricing

## How Much Does DOAS Cost in Toronto?

DOAS units are sized to ventilation rate, recovery type and controls, so each is quoted per site. Written quote within 24 hours of the site assessment.

25/50/25 payment on installs: 25% at order, 50% on install day, 25% on commissioning sign-off. Net-30 for commercial and PM accounts. 

See all pricing

[/pricing/ →](/pricing/)

.

Written per-site quote

Quoted per site within 24 hours

Price depends on tonnage, roof access, curb condition, crane reach and controls. A Red Seal lead confirms all of it on the site assessment before anything is ordered.

Get My Written Quote

[/contact/ →](/contact/)

Why property teams pick us

## Why Choose Rooftop Units Toronto Pros for DOAS?

### Ventilation sized to code

Outdoor air rates calculated to ASHRAE 62.1 for your occupancy, not guessed.

### Energy recovery

Wheels or cores recover heat and moisture so fresh air costs less to condition.

### Works with your RTUs

DOAS handles ventilation so existing RTUs can focus on heating and cooling.

### Demand control

CO2-based control cuts ventilation when rooms empty, saving energy.

Field photos

## Our DOAS Work

Recent GTA rooftops and mechanical rooms. Click any photo to enlarge.

### Before + After

![Stuffy office with high CO2 reading](/images/cards/stuffy-open-office-with-a-wall-co2-monitor-reading.webp)

Before

![Office with CO2 in range after DOAS install](/images/cards/same-office-with-a-co2-monitor-in-range-after-a-do.webp)

After

DOAS units add measured fresh air without oversizing the cooling equipment.

Client Records

## What Clients Say About Our DOAS

> "Our tenants' IAQ requirements needed more outdoor air than the RTUs could handle. The DOAS unit fixed it without replacing the rooftop units."

DCDiane C.Facility director, Markham

> "CO2 complaints in our meeting rooms stopped once the DOAS and demand controls went in."

IFIan F.Facility lead, Markham

> "The Forest Hill school penthouse retrofit ran over the summer break and the plant was back online before staff returned. Clear weekly reports to our facilities office."

GWGrace W.Facilities lead, Forest Hill

> "Short cycling RTU over our North York clinic, fixed after hours so patients were not affected. Readings and photos came with the invoice."

FAFarah A.Clinic manager, North York

> "The quote had the crane, the curb, the permits and HST on one page. The final invoice matched it."

PJPaul J.Property manager, Markham

## RTU offline or chiller alarm?

Red Seal tech on the roof in 2-4 hrs across the GTA core. Call (437) TBD.

(437) TBD

[tel:+14370000000 →](tel:+14370000000)

 

Emergency Service

[/emergency-rooftop-unit-repair-toronto/ →](/emergency-rooftop-unit-repair-toronto/)

Buyer questions

## DOAS FAQs

Still have a question?

A Red Seal lead answers, not a call centre. Written quote within 24 hours.

Book a Site Assessment

[/contact/ →](/contact/)

(437) TBD

[tel:+14370000000 →](tel:+14370000000)

### What is a DOAS system?

A dedicated outdoor air system brings in, filters and conditions fresh outdoor air separately from the heating and cooling equipment. It handles ventilation and humidity so the RTUs do not have to.

### DOAS vs make-up air unit?

A make-up air unit replaces air exhausted by kitchen hoods or garages, usually with heating only. A DOAS provides measured ventilation air for occupants, usually with energy recovery, cooling and dehumidification.

### Does a DOAS replace my RTU?

No. A DOAS handles fresh air; your RTUs still handle heating and cooling. Pairing them often lets existing RTUs run better because they are not fighting large outdoor air loads.

### What does energy recovery save?

An energy recovery wheel or core transfers heat (and with wheels, moisture) between exhaust and incoming air, cutting the energy needed to condition fresh air, especially in Toronto winters and humid summers.

### How much does a DOAS cost?

DOAS units are quoted per site because ventilation rate, recovery type, cooling and controls vary. You get a written quote within 24 hours of the site assessment.

### What filtration can a DOAS provide?

Most DOAS units can carry MERV 13 filtration, which suits offices, clinics and schools with IAQ requirements.

### What is CO2 demand control?

CO2 sensors in occupied spaces modulate outdoor air to match the number of people, reducing ventilation and energy use when rooms are empty.

### Can a DOAS qualify for incentives?

Energy recovery and high-efficiency equipment can qualify for Save on Energy or utility incentives. We confirm eligibility and file.

Keep the whole roof covered

## Related Services

![Direct-fired make-up air unit beside a kitchen exhaust fan on a Toronto restaurant roof](/images/misc/direct-fired-make-up-air-unit-beside-a-kitchen-exh.webp)

[/make-up-air-unit-toronto/ →](/make-up-air-unit-toronto/)

### 

Make-Up Air Unit Service

[/make-up-air-unit-toronto/ →](/make-up-air-unit-toronto/)

Direct and indirect fired MUA repair, replacement and balancing for restaurants and parking garages.

Details + pricing

[/make-up-air-unit-toronto/ →](/make-up-air-unit-toronto/)

 

![Crane lowering a new packaged rooftop unit onto a roof curb in Toronto](/images/misc/mobile-crane-lowering-a-new-packaged-rooftop-unit-.webp) From $9,500

[/commercial-rooftop-unit-installation-toronto/ →](/commercial-rooftop-unit-installation-toronto/)

### 

Commercial Rooftop Unit Installation

[/commercial-rooftop-unit-installation-toronto/ →](/commercial-rooftop-unit-installation-toronto/)

New and added-capacity RTU installs sized with Manual J/S, crane coordinated, commissioned and signed off.

Details + pricing

[/commercial-rooftop-unit-installation-toronto/ →](/commercial-rooftop-unit-installation-toronto/)

![New high-efficiency rooftop units on a Mississauga roof with a rebate application](/images/misc/new-high-efficiency-packaged-rooftop-units-on-a-mi.webp)

[/save-on-energy-retrofit-toronto/ →](/save-on-energy-retrofit-toronto/)

### 

Save on Energy Retrofit

[/save-on-energy-retrofit-toronto/ →](/save-on-energy-retrofit-toronto/)

Pre-audit, application and rebate netted against your invoice on qualifying HVAC retrofits.

Details + pricing

[/save-on-energy-retrofit-toronto/ →](/save-on-energy-retrofit-toronto/)

## Don't See Your GTA City?

Coverage from Toronto to Pearson, Mississauga to Markham. Call 

(437) TBD

[tel:+14370000000 →](tel:+14370000000)

 for a 24-hour written quote.

All Service Areas

[/service-areas/ →](/service-areas/)

 

Get a Written Quote

[/contact/ →](/contact/)

![Packaged rooftop units on a Toronto commercial roof at dusk](/images/misc/toronto-commercial-rooftop-at-dusk-with-a-row-of-p.webp)

24/7 dispatch | 2-4 hr on-roof GTA core

## Ready to Book DOAS?

Site assessment, then a written quote within 24 hours. Parts, labour, crane, permit and HST on one line.

Book a Site Assessment

[/contact/ →](/contact/)

 

Call (437) TBD

[tel:+14370000000 →](tel:+14370000000)

-   24-hour written quote
-   Save on Energy filed for you
-   Red Seal + TSSA + ESA + CRE
-   $5M liability + WSIB