Why Your Classroom Unit Ventilator Blows Cold Air and Why Thats Normal, this weeks video

Interesting video. I can see why teacher wouldn’t like it; 55-60 incoming air would be unpleasant. The unit you showed around 3/4 point looks like it’s had a rough life!

Usually, they pile books and papers on top of the UV which blocks the airflow then they wonder why they have no heat.

In theory, a univent is a wonderful thing — when it's working properly as described. Except for that decidedly cool draught. And having been on both sides of the equation, I can't say that I was happy with the cool draught when I was teaching in spaces with univents…

But, they are cheap to install and relatively efficient.

Really old schools — and I had some to deal with in Vermont — had steam radiators on the walls. Nice and cozy and warm. Ventilation (these were farming communities, and you do need ventilation!) was provided by air outlet grilles in each room which went into a flue which extended through the roof — that pulled the stale air out quite nicely, and infiltration through the windows was the makeup air. Many times those flues had radiators in the bottom to help increase the draught.

Efficiency was… um… poor. But they worked.

Wow so interesting and informative! Are these units usually only installed where high room occupancy is a factor? Does it ever not blow any air? I guess I was a little confused as to when it's done venting even if the thermostat is met.

In many school situations, @RascalOrnery , room occupancy and air exchange rate is the governing design factor. To go back to that Vermont experience I mentioned, when the Arab oil embargo hit and everyone got their pants in a twist about saving energy, a lot of those ventirlator shafts were blocked up. The result was a public health catastrophe among children and teachers… Can't say we didn't warn them, but…

Ever since then I've been a fanatic about air exchange rate!