Learn Hardcore Norwegian: Vi skifter sengetøy ofte fordi det blir fuktig av sjøluften. - We change the bed linen often because it becomes damp from the sea air.

Å skifte means “to change/replace” something with a new one, especially clothes, bed linen, tires, etc. In this sentence, vi skifter sengetøy = we change the bed linen.

Å bytte can also mean “to change,” but it more strongly suggests exchanging or swapping (bytte plass, bytte jobb, bytte penger, bytte med noen).

For bed linen, the natural verb is skifte (or skifte på senga). Bytte sengetøy is understandable, but sounds less idiomatic.

Is sengetøy singular or plural, and why is there no article?

Sengetøy is a neuter, mass noun (like “bedding” in English).

Basic forms:

et sengetøy – (a) set of bedding
sengetøy – bedding (in general)
sengetøyet – the bedding (specific)

In the sentence, we mean “bed linen” in general, as a type of thing we change regularly, so we use it without an article:
Vi skifter sengetøy ofte = We change bed linen often (not one specific, identified set).

Where can the adverb ofte go in the sentence, and is this word order typical?

The given sentence:

Vi skifter sengetøy ofte fordi det blir fuktig av sjøluften.

This is fine and natural. Adverbs like ofte (often) usually come:

after the conjugated verb in simple sentences, or
after the object, if that flows more naturally.

Other correct variants:

Vi skifter ofte sengetøy fordi det blir fuktig av sjøluften.
Ofte skifter vi sengetøy fordi det blir fuktig av sjøluften.

All are grammatical. The differences are subtle in emphasis, not in correctness.

What is det referring to in fordi det blir fuktig?

Here, det refers back to sengetøy (which is a neuter noun).

So:

sengetøy → pronoun det

You could also say:

… fordi sengetøyet blir fuktig av sjøluften.

That would be more explicit. Using det instead of repeating sengetøyet just avoids repetition and sounds very natural in Norwegian.

Why is blir used here instead of er in det blir fuktig?

Blir means “becomes / gets”, indicating a change of state.

det blir fuktig = it gets/becomes damp (because of the sea air)
det er fuktig = it is damp (describing a current state)

In this context, the bedding is not always damp; it becomes damp due to the sea air, again and again over time. That’s why blir is the natural choice.

What is the difference between fuktig and våt?

fuktig ≈ damp, moist
- slightly wet, or with moisture in it/around it
- used for air, clothes, towels, bedding, weather, etc.
våt ≈ wet, soaked
- clearly wet, more water involved

Bedding from sea air usually becomes fuktig (damp), not completely våt (wet), so fuktig is the natural word here.

Why is sjøluften in the definite form instead of just sjøluft?

Sjøluft means “sea air.”
Sjøluften is “the sea air” (definite form).

In Norwegian, the definite form is used more often than in English when you talk about a specific, known environment:

sjøluften = the particular sea air where they live / in that area

So even though English says “because of the sea air,” Norwegian naturally says fordi det blir fuktig av sjøluften (literally “the sea air”).

Formation:

sjø (sea) + luft (air) → sjøluft
sjøluft
- -en (definite suffix) → sjøluften

What does av mean in fuktig av sjøluften, and could you use fra instead?

Here, av is used to express cause:

fuktig av sjøluften = damp because of / from the sea air

Av is the normal preposition when something has a quality caused by something else:

sliten av jobben – tired from work
våt av regnet – wet from the rain

Fra usually means “from” in the sense of origin or movement (from A to B).
Fuktig fra sjøluften sounds odd; av is the idiomatic choice for this “caused by” meaning.

Could the word order be Fordi det blir fuktig av sjøluften, skifter vi sengetøy ofte? Is that correct?

Yes, that is correct and natural:

Fordi det blir fuktig av sjøluften, skifter vi sengetøy ofte.

When a subordinate clause (fordi det blir fuktig av sjøluften) comes first, the main clause inverts (verb before subject):

… skifter vi sengetøy ofte
(not vi skifter)

You can still move ofte around a bit:

Fordi det blir fuktig av sjøluften, skifter vi ofte sengetøy.
Fordi det blir fuktig av sjøluften, skifter vi sengetøy ofte.

All of these are grammatical; they just have slightly different rhythm/emphasis.

How do you pronounce sjøluften, especially the sj sound in sjø?

In standard Eastern Norwegian:

sjø ≈ [ʂøː] (similar to an English “sh” sound, but made with the tongue further back)
sjøluften ≈ [ˈʂøːˌlʉftn̩]

Guidelines:

sj = a “sh-like” sound (not s + j).
ø = like the vowel in French deux or German schön.
luft – like English “looft” (short u like in “put,” and ft is clearly pronounced).
Final -en is an unstressed syllable; the e is very short and weak.

Is there a difference between sjøluft and havluft, or are they interchangeable?

They are very close in meaning, and in many contexts they can be used interchangeably:

sjøluft – sea air (often coastal, fjord, seashore)
havluft – sea air, often with a feel of the open sea / the ocean

Everyday speech often prefers sjøluft / sjøluften, especially along the coast. Havluft / havlufta is also used, but a bit less commonly in some regions.

Can you say this in a more colloquial way, especially the part with skifter sengetøy?

Yes, common colloquial alternatives include:

Vi skifter på senga ofte fordi det blir fuktig av sjøluften.
Vi bytter på senga ofte fordi det blir fuktig av sjøluften.
Vi tar på rent sengetøy ofte fordi det blir fuktig av sjøluften.

Skifte på senga or bytte på senga is a very natural everyday expression for “change the sheets.”