Glazing unit’s dew point

Dew point of glazing or the moment of condensing the glazing.

The words “Why is the glazing sweating?  After all I payed for the best.” are very popular.

In this article I will explain briefly why this is happening.

The dew point of the glazing depends on few factors:

Exterior Temperature

Interior Temperature

Heat Transfer coefficient of the glazing

Air Humidity in the room

The ratio between these four defines the condensation of your glazing.

We hear very often from customers that they are unhappy with the glazing they bought because it is constantly sweating. And every time when a consultant goes on the spot he finds that the humidity of the room is very high. This problem occurs most often when the building is new and the structure is still damp following the wet construction processes. Or the rooms where the problem occurs is usually with higher humidity like kitchens, bathrooms e.t.c.

It goes without saying that the correct choice of the glazing is very important. For low-emission glazing the dew point is way lower but this doesn’t mean that there is no such point.

I’ll explain the dependencies in the diagrams below.

In the first example (diagram 1.1) I’ve used 2 regular float glass 4mm filled with air. The Heat Transfer coefficient of this kind of glazing is usually around U = 2,8-3,0 W/sqm*K. It can be seen from the example that when the Air Humidity is 50% and the Temperature of the room is 20 degrees the dew point comes around -9 degrees. At humidity 60% the dew point is at -3 degrees.

Case 2 (diagram 1.2) shows what is happening when the window is made of 2 float glass 4mm, in which one of them is low-emission and filled with ARGON.  In the right conditions and type of the glasses it can be reached coefficient of Heat Transfer  U = 1,1 W/sqm*K.  The diagram shows at 60% and 70% humidity and 20 degrees room temperature, the dew point hits respectively at -27 and -10 degrees.

In case 3 (diagram 1.3) is used a single glass. The results speak for themselves.

diagram 1.1

diagram 1.2
diagram 1.3

It’s important to understand that the greatest role for the glazing condensation plays the Air Humidity. And of course the type of glazing. It’s been a long time since we used regular glazing in Europe . Having in mind that 85% of a window is glass it is very important not to save money when choosing the glasses.

Here you can download a diagram for defining the dew point of glazing:

Diagrams: Studio CAD

Source: Studio CAD

If you need a professional opinion when choosing glass or glazing don’t hesitate to contact us.

EE0-501 Exam 9L0-206 Exam 4H0-533 IT Exam ST0-119 Dumps HP0-S30 VCE 050-718 VCE HC-019-308-ENU Exam PDF HIT-001 IT Exam 1T6-323 Exam ST0-097 PDF PEGACLSA VCE C8060-350 Exam ML0-220 000-723 Exam CHCA IT Exam P_SOA_EA_70 Exam 0B0-101 Certification P2070-048 PDF C2180-526 VCE 1Z0-232 Dumps C2140-130 VCE NS0-155 VCE VCAD510 920-450 Exam PDF VCS-310 Exam C2090-418 Exam PDF HP3-X07 PDF 000-M159 Certification 050-869 VCE CX-310-019 Exam 250-400 PDF 630-008 Dumps C_TPLM50_95 IT Exam 312-75 PDF 000-644 IT Exam FM0-306 IT Exam HP0-D19 Exam PDF SK0-004 Exam PDF 920-340 PDF ACSO-IJ-PROD-13-03 Certification HP3-X04 Exam HC-012-224-ENU PDF HP2-E53 Dumps STI-884 Exam CAT-040 HP0-Y50 IT Exam P6040-025 000-M227 VCE P9050-005 Certification 1Z0-805 VCE

5 D. Nemirov Str.
Sofia 1324, Bulgaria, EU




Studio CAD's Cloud

Studio CAD's Cloud