Det er umuligt at aflæse elmåleren.

In this sentence, det is a dummy subject, similar to English it in It is impossible to read the electricity meter.

So:

• Det er umuligt ... = It is impossible ...

It does not refer to a specific thing. Danish often uses det this way with expressions about weather, time, and general statements:

• Det er koldt. = It is cold.
• Det er svært at forstå. = It is hard to understand.

Because the adjective agrees with det.

The base form is:

• umulig = impossible

But when an adjective describes something with det, it usually takes -t:

• Det er umuligt. = It is impossible.
• Det er svært. = It is difficult.
• Det er let. = It is easy.

So umuligt is the correct form here.

Here at is the infinitive marker, like English to.

So:

• at aflæse = to read / to take a reading from

This is very common after adjectives like umuligt, svært, let, and so on:

• Det er svært at forstå. = It is difficult to understand.
• Det er let at se. = It is easy to see.
• Det er umuligt at aflæse elmåleren. = It is impossible to read the electricity meter.

Aflæse usually means to read off, to take a reading from, or to read a measurement on something.

It is often used for instruments, meters, gauges, thermometers, displays, and similar things.

Examples:

• aflæse en måler = read a meter
• aflæse temperaturen = read the temperature
• aflæse tallet på displayet = read the number on the display

So aflæse is more specific than læse.

• læse = read, in a broad sense
• aflæse = read off a value or measurement from something

Because elmåleren is the definite form: the electricity meter.

In Danish, the definite article is often attached to the end of the noun:

• en elmåler = an electricity meter
• elmåleren = the electricity meter

This is one of the first big differences from English. Instead of putting the before the noun, Danish often adds -en or -et to the noun itself.

Because Danish, like English, often makes compound nouns, and Danish usually writes them as one word.

So:

• el = electricity / electric
• måler = meter
• elmåler = electricity meter / electric meter

Then in the definite form:

• elmåleren = the electricity meter

This is very normal in Danish:

• bil
  • dør = bildør = car door
• kaffe
  • kop = kaffekop = coffee cup

The structure is:

• Det = dummy subject
• er = is
• umuligt = impossible
• at aflæse = to read / to take a reading from
• elmåleren = the electricity meter

So the full pattern is:

Det er + adjective + at + infinitive

This is a very useful Danish pattern:

• Det er svært at lære dansk. = It is difficult to learn Danish.
• Det er nemt at glemme det. = It is easy to forget it.
• Det er umuligt at aflæse elmåleren. = It is impossible to read the electricity meter.

Yes. That is also correct and very natural.

Compare:

• Det er umuligt at aflæse elmåleren. = It is impossible to read the electricity meter.
• Det er ikke muligt at aflæse elmåleren. = It is not possible to read the electricity meter.

The difference is mainly style and strength:

• umuligt can sound a bit stronger or more direct
• ikke muligt can sound slightly more neutral or formal

Both are good Danish.

Approximate help for an English speaker:

• aflæse sounds roughly like ahf-less-uh
• elmåleren sounds roughly like el-moh-luh-run

A few important points:

• æ in aflæse is a front vowel, somewhat like the vowel in cat, but not exactly the same
• å in måler sounds somewhat like the vowel in more in many English accents
• the final -er in Danish is often pronounced weakly, more like -uh

Also, spoken Danish is often softer and less clearly pronounced than the spelling suggests, so listening to native audio is especially helpful.

Not really.

• læse means read in a general sense
• aflæse specifically means read off a value/measurement

With a meter, aflæse is the natural verb because you are checking the numbers shown on the device.

So for a utility meter, thermometer, or gauge, aflæse is usually the better choice.

Yes. The sentence itself does not say why it is impossible. It only states the result: the meter cannot be read.

Depending on context, it could mean:

• the display is broken
• the numbers are faded
• the meter is too dirty
• the meter is blocked
• the light is too poor
• the glass is scratched
• the person cannot make out the reading

So umuligt at aflæse elmåleren focuses on the inability to get a reading, not the specific reason.

Yes, it sounds natural.

It is the kind of sentence you might see or hear in contexts like:

• utility inspections
• maintenance reports
• customer service
• technical descriptions
• complaints about access or visibility

A native speaker might also say similar things such as:

• Elmåleren er umulig at aflæse.
• Det er svært at aflæse elmåleren.
• Man kan ikke aflæse elmåleren.

All of these are natural, but your original sentence is perfectly good Danish.