Re: ice age

Posted by HH56 On 2012/8/12 9:42:49

Most household units are filtered and recirculated unless the AC is of the swamp cooler variety.

Majority of cars up until the early 60s and any with hang on units were mostly recirculated. Packards own 55-6 system would do either. If you just turn AC on, then recirc but if you move the left fresh air vent knob to "cold" position, 100% outside. Trunk units were recirculated. The pair of nominally sized outside air vents provided a bit of fresh if the owner manually opened them. The controls for the vents were on the package shelf so doubt if they were played with much.

After the early 60s, the majority of factory in dash jobs started using fresh air drawn from the cowl area as normal supply. Most had an extra button labeled fast cool or something along those lines to close the outside door and recirculate. Downside to the recirc on those systems was no temp control and the blower noise increased substantially since it was generally on the highest speed.

A few systems did have an actual recirc button where you could vary temp and fan but the noise level was still a bit higher that would be present if outside air was used.