WOBO thanks the Building Science Corporation for the link to their latest article.
HVAC systems and windows have almost as interesting a relationship as the “Odd Couple” – Oscar and Felix – did in the 70’s1. However, unlike Oscar and Felix’s relationship, the relationship between HVAC systems and windows has changed dramatically over time. How they now live together is interesting and changing.
Way back in the day we had “lousy” windows. They were thermal nightmares. Insanely uncomfortable in the winter and ugly uncomfortable in the summer. You couldn’t be near them when it was cold or when it was hot and sunny. Thank god for HVAC systems. Good HVAC systems saved “lousy” windows. We had to blow warm air against them in winter to raise the mean radiant temperature and blow cold air against them in the summer to lower the mean radiant temperature. Laying out ductwork was a big deal.
In cold climates warm air would be blown up against the cold glass from floor registers located under the windows. The “blown” air would rise to the ceiling and the assumption was that the air would flow across the ceiling, be cooled, fall downwards and be picked up at the bottom of interior walls by a return register (Figure 1). read more…
Read the entire article at buildingscience.com.