Indoor air quality can be manged by a combination of two strategies: controlling the amount of internal pollution in the first place followed by continuous replacement of stale air with fresh air.
- Combustion ventilation: Vented range hoods; vented water heaters; heating stoves with piped in make-up air and sealed combustion chambers; no open fireplaces
- Moisture control: Range hoods; bathroom exhaust fans; dryer vents; dehumidifiers if necessary
- Low or no volatile organic compounds (VOCs): Formaldehyde-free building materials; low or no VOC paints, finishes, carpet and upholstery; outside storage for and use of VOC cleaning supplies and shop chemicals such as acetone and paint thinner
- Radon mitigation during construction or as a retrofit
- Air barriers between attached garage and living quarters; no duct work penetrations
- Enough strategically placed operable windows for adequate ventilation when the outside environment cooperates
- Heat recovery ventilator (HRV) or energy recovery ventilator (ERV), either free-standing or tied into the central HVAC to replace 30 - 50% indoor air with outdoor air every hour
We will have no other sources of open combustion such as stoves and fireplaces but will have a gas tankless water heater and gas clothes dryer properly vented to the outside. Since we are building new, we expect to have good control over VOCs. Radon gas will be intercepted and led to daylight by the gravel backfill in the French drains and the AGS conduits and we have used plastic sheeting under the slab. Air barriers between the garage and living quarters with no un-caulked penetrations are not only required by code but make perfect sense and we will be in compliance.
As a value-added feature, the ERV will be situated so that it pulls air through vents in the partition between the living quarters and the earth contact wall so as to bring more air into contact with the wall than would otherwise be possible, thereby enhancing the performance of the AGS system.
|ERV in summer mode. Hot, humid incoming air is cooled|
and dried by the outgoing air by passing near each other
in the heat exchanger without actually physically mixing