Denne dyne er for varm, så jeg tager en anden dyne i stedet.

Denne means this and is a demonstrative adjective.

So:

• denne dyne = this duvet
• den dyne usually means that duvet or the duvet, depending on context

A native English speaker often expects den to mean that, but in Danish the system is a bit different. If you want to point to something near you and say this, denne is a standard written form for a common-gender singular noun like dyne.

In everyday spoken Danish, people very often say den her dyne instead of denne dyne.

After denne, the noun stays in its basic singular form:

• denne dyne
• not denne dynen

This is important, because English speakers often expect something like this the duvet, but Danish does not work that way.

Compare:

• dynen = the duvet
• denne dyne = this duvet

So when a demonstrative like denne is used directly before the noun, you do not add the definite ending.

Because dyne is a common-gender singular noun.

In Danish, predicate adjectives agree with the noun:

• common gender singular: varm
• neuter singular: varmt
• plural: varme

So:

• En dyne er varm
• Et tæppe er varmt
• Dyner er varme

Since dyne takes en, not et, the correct form is varm.

No. In this sentence, for means too.

So:

• for varm = too warm

This is a very common source of confusion for English speakers, because Danish for does not always match English for.

Examples:

• for dyr = too expensive
• for sent = too late
• for stor = too big

So Denne dyne er for varm means the duvet is excessively warm, not that it is warm for someone.

Here så means so in the sense of therefore / as a result.

The sentence is built from two main clauses:

• Denne dyne er for varm
• så jeg tager en anden dyne i stedet

So the logic is:

This duvet is too warm, so I’m taking another one instead.

This så connects cause and result.

Because Danish verbs do not change for person the way English verbs sometimes do.

The present tense of at tage is tager, and it stays the same with all subjects:

• jeg tager
• du tager
• han tager
• vi tager

So unlike English, where you have I take but he takes, Danish just uses tager for everyone in the present tense.

Anden here means another or a different.

So:

• en anden dyne = another duvet / a different duvet

This is an indefinite expression: you are not talking about one specific previously identified duvet, just a different one.

A useful contrast is:

• en anden dyne = another / a different duvet
• den anden dyne = the other duvet

That difference matters a lot in Danish.

I stedet means instead.

So:

• jeg tager en anden dyne i stedet = I’ll take another duvet instead

There are two related expressions:

• i stedet = instead
• i stedet for = instead of

Examples:

• Jeg tager en anden dyne i stedet. = I’m taking another duvet instead.
• Jeg tager en anden dyne i stedet for denne. = I’m taking another duvet instead of this one.

In your sentence, the standalone instead meaning is enough, so for is not needed.

Yes, it could.

Both are possible:

• jeg tager en anden dyne i stedet
• jeg tager en anden i stedet

The second version is shorter and still natural if the context is clear. The first version repeats dyne for clarity or emphasis.

English does something similar:

• I’ll take another duvet instead
• I’ll take another one instead

So the repetition is not required, but it is perfectly normal.

Because så here is functioning as a coordinating conjunction joining two main clauses.

That means the second clause keeps normal main-clause word order:

• så jeg tager ...

This is different from cases where så is placed at the beginning of a new sentence or clause as an adverb-like element:

• Så tager jeg en anden dyne.

There, så takes first position in the clause, so the verb comes before the subject: tager jeg.

So both are possible, but they are structured differently:

• Denne dyne er for varm, så jeg tager en anden dyne i stedet.
• Denne dyne er for varm. Så tager jeg en anden dyne i stedet.

It is correct and natural, especially in writing or careful speech, but in everyday spoken Danish many people would more often say:

• Den her dyne er for varm, så jeg tager en anden dyne i stedet.

So the difference is roughly:

• denne dyne = a bit more formal, written, or careful
• den her dyne = very common in speech

A learner should understand and be able to use both.