Air exchanger (HRV/ERV): installation survey

An air exchanger before the work: the exhaust the code asks by bedrooms, the flows and the balance, the duct runs and the exterior hoods.

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Air exchanger (HRV/ERV): installation survey: a filled-in survey in MesuPro — A survey made with this template, in the app.

What you measure

The template's tables and their columns, as the app shows them. Calculated columns fill in as you type.

Air exchangers

Dwelling
Unit typeChoices: HRV ERV
Make and model
Location
Bedrooms
Floor area
IRC rate calculated
Required exhaust, minimum
Required exhaust, maximum
Rated flow, maker
Exhaust at normal speed
Above the minimum calculated
Below the maximum calculated
Exhaust, high speed
Fresh air, high speed
Balance gap calculated
Condensate drainChoices: Trap loop to a floor drain Condensate pump To install None (ERV)
Electrical outletChoices: Within 3 ft To add
Main controlChoices: Wall control in the living area Dehumidistat with a manual override Integrated control only
Notes

Duct runs

RunChoices: Fresh air from outside Exhaust air to outside Fresh air to the house Stale air from the house
Room or branch
DuctChoices: Insulated flexible Flexible Rigid metal
Diameter
Length
Design flow
InsulationChoices: Insulated, vapour barrier Insulated Not insulated
GrilleChoices: Ceiling High on a wall Low on a wall or floor Hood outside
Notes

Exterior hoods

HoodChoices: Fresh air intake Exhaust outlet
Wall
Height above the ground
Expected snow depth
Minimum height, code or maker
Height margin calculated
Distance to the other hood
Nearest contaminant source
Distance to that source
Distance to a vented soffit
Hood typeChoices: Standard Anti-gust
Notes

About this template

Before an HRV or ERV goes in: the exhaust the code asks by bedrooms (NBC Table 9.32.3.3, or the IRC rate worked out from the floor area), the flows at normal and high speed with their margins and balance, the duct runs totalled by run, and each exterior hood's height and distances.

Guide and sources

One row per air exchanger, an HRV or an ERV. Count the bedrooms and type the required exhaust from the code that applies: in Canada, NBC Table 9.32.3.3 (3 bedrooms: 22 to 32 L/s, 46.6 to 67.8 CFM); in the US, the IRC rate the sheet works out from the floor area and the bedrooms (Equation 15-1), a minimum only. Check the edition your province, state or city enforces. Then the exhaust at normal speed shows its margin to each end, never a verdict.

Balancing: Venmar reads the exhaust, then the fresh air, at high speed, on the unit's pressure taps, and considers the unit balanced within ±10 CFM; the NBC asks the maker's start-up procedure, balancing included. Each duct run adds up by run: Venmar needs no balancing when the stale air side (from the house and to outside) and the fresh air side total within 50 ft of each other, unless the local code asks for it.

The exterior hoods: the height of each opening above the ground, the distance between the two hoods and to the nearest contaminant source. NBC 9.32.3.13: an intake at least 450 mm (17 3/4 in) above the ground or the expected snow, and 1 800 mm from gas vents and oil fill pipes; Venmar: the hoods 6 ft apart and 18 in above the ground; the IRC: an exhaust 10 ft from a mechanical intake. The client's report shows the units, the flows, the ducts and the hoods; the requirements and margins stay in your team's report.

Sources

Venmar, Constructo 1.0 installation guide Manufacturer dataInstallation guide for Venmar AVS units, Constructo 1.0 HRV and Constructo 1.0 ERV, Venmar Ventilation (guide hosted by a building publisher), 06010A rev. 13, pp. 4 to 15. Checked Oct 16, 2026
IRC 2021, M1505 CodeInternational Residential Code 2021, M1504.3 Exhaust openings and M1505.4 Whole-house mechanical ventilation (as adopted in Colorado), International Code Council (read in a state adoption on UpCodes; Equation 15-1 in the City of Scottsdale's 2021 IRC handout), 2021, M1504.3, M1505.4.3 (Equation 15-1) and M1505.4.4. Checked Oct 16, 2026
Venmar, Constructo 1.0 HRV sheet Manufacturer dataAVS Constructo 1.0 HRV product sheet, Venmar Ventilation (sheet hosted by a building publisher), product sheet no. 91047 (12/07). Checked Oct 16, 2026
NBC 2020, 9.32.3 CodeNational Building Code of Canada 2020, 9.32.3 Mechanical ventilation (Table 9.32.3.3, ducts, heat recovery ventilators, outdoor intake and exhaust openings), National Research Council Canada, 2020, Vol. 2, pp. 9-212 to 9-223 (Quebec: Code de construction, chapitre I, in force 2025-04-17). Checked Oct 16, 2026