Kad dođeš kući, namjesti grijanje na nižu temperaturu i otvori prozor na pet minuta.

Both mean when.

• kad = shorter, very common in everyday speech
• kada = fuller form, sometimes a bit more formal or emphatic

In this sentence, kad is completely natural.

This is a very normal Croatian pattern.

Dođeš is the 2nd person singular present of the perfective verb doći. After kad, Croatian often uses the present form of a perfective verb to talk about a future event:

• Kad dođeš kući, ... = When you get home, ...

English actually does something similar:

• not When you will get home
• but When you get home

So the Croatian structure is not strange once you compare it to English when-clauses.

Yes. Kući is a special fixed form related to kuća (house/home), and learners usually just memorize it as the normal word used for home in phrases like:

• ići kući = to go home
• doći kući = to come home
• sam kući = I’m at home

So in this sentence, kući is simply the standard way to say home after dođeš.

Yes. They are imperatives addressed to one person.

• namjestiti → namjesti
• otvoriti → otvori

So the sentence is giving instructions to you (singular).

If you were speaking to more than one person, you would use:

• namjestite
• otvorite

Here grijanje is the direct object of namjesti.

The noun grijanje is neuter singular, and for this noun the nominative and accusative forms are the same:

• nominative: grijanje
• accusative: grijanje

So even though it is the object, its form does not visibly change.

Because Croatian uses na + accusative after verbs like set, adjust, or change to a certain level.

So:

• namjestiti na temperaturu = to set to a temperature

In this phrase:

• temperaturu = accusative singular of temperatura
• nižu = accusative singular feminine of niži (lower)

So na nižu temperaturu literally means to a lower temperature.

Because the idea is lower than it is now, not simply low in an absolute sense.

• nižu temperaturu = a lower temperature
• nisku temperaturu = a low temperature

In practical instructions like this, Croatian often prefers the comparative because you are adjusting a setting relative to its current value.

Here na + accusative expresses duration:

• na pet minuta = for five minutes

So:

• otvori prozor na pet minuta = open the window for five minutes

This is different from:

• za pet minuta = in five minutes

So na pet minuta tells you how long the window should stay open.

After numbers 5 and above, Croatian normally uses the genitive plural of the noun.

So:

• pet minuta = five minutes
• deset minuta = ten minutes

That is why minuta appears here.

The key verbs here are perfective:

• doći → dođeš
• namjestiti → namjesti
• otvoriti → otvori

Perfective verbs fit because the sentence describes single, completed actions:

1. you arrive home
2. you adjust the heating
3. you open the window

This is exactly the kind of situation where perfective verbs are very common in Croatian.

Not completely, but the given order is the most neutral and natural for a learner:

• Kad dođeš kući, namjesti grijanje na nižu temperaturu i otvori prozor na pet minuta.

Croatian word order is flexible, but changing it can affect emphasis or sound less natural. So this version is a very good model to copy.

Because Kad dođeš kući is a subordinate time clause placed before the main clause.

So Croatian writes:

• Kad dođeš kući, ...

This is similar to English:

• When you get home, ...

If the time clause came later, the punctuation would change:

• Namjesti grijanje na nižu temperaturu i otvori prozor na pet minuta kad dođeš kući.

A few helpful approximations:

• dođeš ≈ DOH-jesh, with đ as a soft dy/j sound
• grijanje ≈ gri-YA-nye
• kući ≈ KOO-chee
• nižu ≈ NEE-zhu

Also, Croatian spelling is generally very regular, so once you learn letters like č, ć, đ, š, ž, pronunciation becomes much easier.