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Open_ERV Profile picture
Open_ERV
@open_erv
I make machines that improve indoor air quality, ERVs are on hold while I focus on the Big Quiet Air Purifier. 1110 cfm flow through MERV-13, at only 36.3 dBa.
Jun 20, 2025 • 4 tweets • 1 min read
My friend and comrade Austin graduated recently and posted on Linkedin today that he is committing full time to start a business making and selling window mounted energy recovery ventilators at a great price ($300 USD each 60 cfm 80% efficiency including water vapor). Link below. swervair.com
Jan 16, 2025 • 4 tweets • 1 min read
A big quiet fan with 10 merv 13 filters is ready to go to foulab tonight, to be the first actual real world install of the bqf in a community space! Filtering tons of air very quietly :). Should be about 1200 cfm actual cadr with these crummy filters, at 40.6 dBa. Image I made a video so you can see the air flowing around with some fog/"smoke". It's the actual cadr that matters of course.
Dec 7, 2024 • 4 tweets • 1 min read
It must be about eight times now people have emailed me needing an erv in a hurry, usually to solve a health problem that requires far more than 60 cfm. My advice is that erv is a long term value proposition. If you need clean outdoor air in a hurry: take a small pc fan ( An arctic P12 is good) and put it in the window, but put cloth or tape over it to restrict the airflow. This is much better than an open window because an open window varies by a factor of thirty in the flow you get depending on conditions. It's always too much or too little.
Nov 16, 2024 • 4 tweets • 2 min read
In all the filter/cr boxes I've seen, the interior and even bottom side of the cube is not used. Understanding that larger filter area does not increase cost per cubic meter of clean air, I'm exploring designs that cram tremendous amounts of filter into nearly the same space Image
Image
Image This one has ten filters in a box of nearly the same dimensions of one that usually has only four. It does take a little extra space to let the air flow around. It's a little sturdier than it needs to be because I'm using timbers as spacers. 1/2 in cnc cut birch ply instead?...
Mar 3, 2024 • 5 tweets • 2 min read
Here is the "concept sketch" of a window mount energy recovery ventilator that should harvest as much energy and give as much fresh air as a $1300 centralized unit, with less noise, for maybe $250 in parts. The top panel is removed so you can see inside. Image You see 4 pc fans (icegale Xtra 140 mm 169 cfm), each pair pointed in opposing directions. You power up the right one at the right time to reverse airflow direction. Grey blocks are the heat exchangers. Pink is fiberglass, to absorb noise. Casing is waterproof 3mm plywood.