Single, double or HR++: which glass to choose?
The decision guide for every glass job: what the glass types do, where they belong and when which choice makes sense.
Single glazing is one sheet of glass: cheap, but it barely insulates — you still find it mainly in pre-war homes and outbuildings. Double (insulated) glazing consists of two sheets with a cavity in between. HR++ glass adds a heat-reflecting coating and a gas filling and thus insulates distinctly better than plain double glazing — you also notice the difference in street noise and condensation on the glass.
The rule of thumb when replacing: if a new pane has to go in anyway, choose HR++. The price difference with plain double glazing is small compared to the job as a whole, and you live with the choice for decades. Upgrading from single glazing to HR++ costs € 100-300 per m²; when measuring up, the glazier checks whether the rebate is deep enough and the frame sound.
Safety glass (toughened or laminated) belongs where people can fall or walk into the glass: in and next to doors, in low glazing and in balustrades. Toughened glass breaks into granules instead of sharp points; laminated glass stays in one piece thanks to a film. With custom-cut glass for those spots, the professional advises on it as standard.
Not sure what is in your frame now? Hold a small flame or light near the glass: if you see the reflection doubled, it is insulated glazing. What each choice costs is in the price index — and a new pane is quoted to measure.