Many windows have nowadays Low-E, low-emissivity, coats to enhance its energy efficiency functions. That is why it is relevant to ask can Sparklike Handheld measure Low-E coated IG units.
The answer is yes, if the other side of the double-glazed glass is clear glass. That is only when you can measure through it.
With Sparklike Laser you are able to measure double and triple glazed insulating glass units with most coatings and lamination.