In the Netherlands, insulated glass is rated by a standardized rating system, classifying it into 3 categories by the u-value:
- HR : U value between 2.0 and 1.7
- HR+ : U value between 1.6 and 1.3
- HR++ : U value less than 1.2
The price difference between these types of insulated glass is quite large. After the glass has been installed, is there any simple way to measure the U value or otherwise check the type? I guess it would be quite easy for a swindling contractor to sell HR++ and install HR without it ever being noticed?
Best Answer
This is hard to do and I agree that there is a big range of cost between basic insulated sealed units and some of the high performance glass units which can be triple the cost. Here in Canada when we install a commercial glass project we are required to provide warranty documentation from the glass supplier which shows the makeup of the sealed units ( glass thickness, low-e coatings and any gas filling details ). This information even provides the invoice numbers for glass provided for the job and can be a great help in matching up replacement glass when breakage or insulated glass failure becomes an issue down the road. I would try to get this documentation from window / glazing contractor. If this is not available there is a measuring tool from CR Laurence that can tell you the glass thicknesses, airspace thickness and what surface the low-e coating is on. It won't tell you the type of low-e glass nor whether there is any argon gas but will provide you with basic information. A professional glazier can often take a look at the colour of the glass from inside and outside to point you in the right glass type direction as well. Good luck!