OpenERV

Fresh outdoor air all year round.

The TW4 decentralized Energy Recovery Ventilator transfers clean outdoor air inside and moves polluted air outdoors, while harvesting ~90% of the heat energy – so you get fresh air without the downsides of heating or cooling it.

The WM12 is basically two TW4 modules side by side in a piece of tough polypropylene foam, so you can put it in a window.

The design is now in beta.  People who request a unit by email will be contacted one at a time as units become available, starting with those most able to handle potential complications that come with the beta phase.

Provides fresh air during hot or cold weather, without allowing the loss or intrusion of (much) heat energy.  

Core performance figures: 

~90% sensible, ~80% latent heat recovery on medium speed.  Slightly higher at low speed, slightly lower on max.  This varies very little with temperature, humidity or season.

 High air flow – 60 CFM actual average net fresh air in heat recovery mode on maximum speed.

Extremely quiet  – ~0.25 Sone (~37 dBa) on medium, essentially inaudible on low, ~42.5 dBa on max. 

~21x greater rate of return on investment, compared with typical, conventional ductless ERV units, due to long term design, maintenance costs, higher energy recovery and other factors combined.   ~3x the return on investment of typical ducted HRV/ERV units. >10x ROI of photovoltaic panels in many areas like Ottawa, Canada.  See spreadsheet on learn more page for details.

Other details include:

Optional HEPA (H13) filter, using widely available filters (requires the outdoor plate attachment and hood)

Designed and built to last for >50 years, for greatly superior return on investment, with no long term component availability concerns.

Can be configured to work with common home automation systems, including Google Home, Alexa and Home Assistant for scheduling, many kinds of sensor-based operation, interfacing with knobs and switches without wiring, etc using MQTT. 

Can be controlled over WiFi using MQTT, including from a phone.

Very low electrical energy consumption –  2 watts on low, 7 watts at maximum power.

Effectively reduces CO2 levels, reduces transmission of airborne pathogens and improves Indoor Air Quality in all metrics.

Storm valve add-on to prevent intrusion of air or water during a storm (requires exterior plate and hood)

Automatic wind compensation using a very nice pressure sensor, to ensure balanced air flow in both directions, and a precisely controllable influence on total net pressure in the building.