Source criticism: 503, 0 and null

If you ask for the energy label of a detached house, the answer can be HTTP 503: the house is not in the energy label corpus yet. That means “not looked up”, not “no energy label”.

For Østre Gasværk the energy label returns 404. Here it has been looked up, and no label was found. That is a different answer from 503.

The apartment building from 1867 has a property value of DKK 0 in the 2020 valuation. That is not the property's value; there is just no public value to show. Write “no public value”.

At the top of Himmelbjerget the noise is null. The 2017 noise mapping only covers the largest roads and railways, Copenhagen Airport and the four largest cities. null means “not mapped at or above the threshold”, not “quiet”. At Rådhuspladsen in Copenhagen the same lookup gives 60-64 dB from road traffic.