RenewAire CO2-W (wall) and CO2-D (duct)

At a glance

• In its favour
• Plain fact
• Worth knowing
• Not stated by the maker

• In its favour: Can be set under 800
• In its favour: The trip point can be set from 500 to 1,500 ppmSo 750 is in range. The gap before it switches back can be 25 to 200 ppm.
• In its favour: Documented for the EV90, EV130, EV200, EV Premium and EV Premium+In RenewAire’s CO₂ wiring supplement (February 2026). The Aeri MT’s submittal lists them as accessories too.
• Not stated by the maker: Its factory setting isn’t publishedNor how the trip point is programmed. Have the installer check and set it.
• Plain fact: EV Premium: wired between its 24VAC and HIGH terminalsWhen CO₂ drops, the unit goes back to normal, or off if it was installed that way. Ask for normal.
• Worth knowing: EV90 and EV130 take unpowered controls onlyNever connect power to their control terminals.

Setting it for a bedroom

HouseExhale’s setting: switch up at 750 ppm and back at 650, or ramp from 600 to full by 750. Never above 800.

1. Set the relay trip point to 750 ppm and the gap to 100 ppm, so it switches back at 650.
2. Have the unit wired to stay on its normal speed below the trip point.
3. Check with your own monitor that high speed comes on and the bedroom averages 800 or less.

A Danish study ran a bedroom fan from about 900 ppm and the nights still averaged 835, so a control has to start below the goal. Good home CO₂ sensors are rated within about 55 to 90 ppm at 800, and the night average includes the climb after bedtime, so 750 on and 650 off leaves room for both. A control in the return duct mixes the bedroom with empty rooms, so it needs lower settings still (about 650 on, 550 off), and your monitor in the bedroom has the final word. These are HouseExhale’s numbers: no study has tested a control against an 800 night average yet.

What it works with

Documented for: RenewAire EV90, EV130, EV200, EV Premium, EV Premium+ and SL units, and the Aeri MT (its submittal lists them).

• RenewAire EV Premium S

  Documented by RenewAire

  112 cfm at 0.5 in.

• 

  RenewAire EV Premium M

  Documented by RenewAire

  210 cfm at 0.5 in.

• RenewAire Aeri MT (ET-255MF-P340-XC0)

  Listed in its submittal

  231 cfm at 0.5 in.

How to add CO₂ control to an HRV or ERV · HRV and ERV units

Specs

Models

CO2-W, wall (131304); CO2-D, duct (131305)

Sensor

True CO₂ (NDIR)

Relay

Normally open, 2 A at 140 V AC or 30 V DC

Other outputs

0–10 V (default), 0–5 V or 4–20 mA

Power

20–28 V AC or DC

Display

Two-line, 8-character LCD

From the maker’s documents, read October 17, 2026. Prices are before tax and shipping and change often.

Made by the ventilator’s maker

Sold for a maker’s own units, with the wiring in its manuals. An installer fits them.

• 

  Fantech CO2RT-R (item 99315)

  Setting range not published

  Wall CO₂ controller with a relay

• S&P SCO2-W

  Can be set under 800

  Wall CO₂ control for S&P ventilators

• 

  Zehnder CO₂ sensor (0–10 V) with the Option Box

  Can be set under 800

  Wall CO₂ sensor for ComfoAir units