Το σπίτι, από το μπαλκόνι του οποίου φαίνεται η θάλασσα, είναι πιο όμορφο απ’ όσο περίμενα.

The sentence has two main parts:

• Το σπίτι … είναι πιο όμορφο απ’ όσο περίμενα
  = The house … is more beautiful than I expected

And inside it, there is an inserted relative clause:

• από το μπαλκόνι του οποίου φαίνεται η θάλασσα
  = from whose balcony the sea can be seen / from the balcony of which the sea is visible

So the sentence works like this:

• Main noun: Το σπίτι = the house
• Extra description about the house: από το μπαλκόνι του οποίου φαίνεται η θάλασσα
• Main statement: είναι πιο όμορφο απ’ όσο περίμενα

In natural English order, it is something like:

• The house, from whose balcony the sea is visible, is more beautiful than I expected.

του οποίου means whose or more literally of which.

It refers back to το σπίτι.

So:

• το σπίτι = the house
• του οποίου = whose / of which

Then:

• από το μπαλκόνι του οποίου
  literally = from the balcony of which
  naturally = from whose balcony

This is a fairly formal/literary structure in Greek. It is used when English would often use whose for things as well as people.

Because it agrees with the noun it refers to, which is το σπίτι.

Here is the logic:

• σπίτι is singular
• σπίτι is neuter
• so the relative form must be genitive singular neuter

That form is:

• του οποίου

A quick comparison:

• ο οποίος = masculine nominative singular
• η οποία = feminine nominative singular
• το οποίο = neuter nominative singular
• του οποίου = masculine/neuter genitive singular
• της οποίας = feminine genitive singular
• των οποίων = genitive plural

So του οποίου is used because the clause means the balcony of the house.

Because it expresses possession.

The phrase is really:

• το μπαλκόνι του σπιτιού = the balcony of the house

When that becomes a relative structure, του σπιτιού turns into του οποίου:

• από το μπαλκόνι του οποίου
  = from the balcony of which
  = from whose balcony

So the genitive is there because the house is the possessor of the balcony.

Here από means from, and in Modern Greek it normally takes the accusative.

So:

• το μπαλκόνι is accusative singular
• that is why we get από το μπαλκόνι

Examples:

• από το σπίτι = from the house
• από τη θάλασσα = from the sea
• από τον δρόμο = from the street

So in this sentence:

• από το μπαλκόνι του οποίου
  = from its balcony / from whose balcony

The subject is η θάλασσα.

So:

• φαίνεται η θάλασσα
  literally = the sea appears / is visible

Since η θάλασσα is singular, the verb is singular:

• φαίνεται = third person singular

Even though η θάλασσα comes after the verb, it is still the subject. Greek word order is more flexible than English.

So this part means:

• από το μπαλκόνι του οποίου φαίνεται η θάλασσα
  = from whose balcony the sea is visible

Because Greek allows flexible word order, especially when the meaning is already clear from articles and endings.

Both of these are possible in principle:

• η θάλασσα φαίνεται
• φαίνεται η θάλασσα

In this sentence, φαίνεται η θάλασσα sounds natural and flows well inside the relative clause.

Putting the verb first can make the clause feel a bit more descriptive or observational:

• from whose balcony the sea can be seen

So the word order is natural Greek, not something strange or incorrect.

In this sentence, φαίνεται means is visible or can be seen.

The verb φαίνομαι / φαίνεται can have several related meanings, depending on context:

• seem
• appear
• be visible

Here, because we have from the balcony, the meaning is clearly visual:

• από το μπαλκόνι … φαίνεται η θάλασσα
• the sea is visible from the balcony
• you can see the sea from the balcony

So although φαίνεται literally connects to appears, the most natural English meaning here is is visible / can be seen.

Because it agrees with το σπίτι, which is neuter singular.

• όμορφος = masculine singular
• όμορφη = feminine singular
• όμορφο = neuter singular

Since σπίτι is neuter:

• Το σπίτι είναι όμορφο
• Το σπίτι είναι πιο όμορφο

Greek adjectives must agree with the noun they describe in gender, number, and case.

This is a comparative structure.

• πιο όμορφο = more beautiful
• απ’ όσο περίμενα = than I expected

So together:

• πιο όμορφο απ’ όσο περίμενα
• more beautiful than I expected

A useful way to think about it:

• πιο + adjective = more + adjective
• απ’ όσο + verb/clause = than / than what / than the degree that

The full form of απ’ is από:

• από όσο
• contracted before a vowel: απ’ όσο

This is very common in Greek.

Because από is often shortened to απ’ before a following vowel.

Since όσο starts with a vowel, Greek commonly writes:

• απ’ όσο

instead of:

• από όσο

Both reflect the same word, but the shortened form is very natural and very common in writing.

You will often see similar contractions such as:

• απ’ όλα = from all / than all
• απ’ αυτό = from that
• απ’ ό,τι = than what

Because in this kind of sentence, Greek often uses the imperfect to mean I was expecting or I had expected, depending on context.

• περίμενα = imperfect, I was expecting / I expected
• περίμενα here sounds very natural after απ’ όσο

So:

• πιο όμορφο απ’ όσο περίμενα
• literally = more beautiful than I was expecting
• naturally = more beautiful than I expected

In many cases, English uses a simple past where Greek uses the imperfect.

Not in exactly the same neat way.

που is the most common relative word in Greek, but του οποίου is used when you specifically need a possessive meaning like whose / of which.

This sentence means:

• the house, from whose balcony the sea is visible

That possessive idea is expressed very clearly by του οποίου.

A more everyday rewording with που might be possible, for example:

• Το σπίτι, που από το μπαλκόνι του φαίνεται η θάλασσα, είναι…

This is understandable, but it is structured differently:

• που = that/which
• του = its

So the original sentence is more elegant and more formal, while the που version is more conversational.

Because that part is a non-essential relative clause: it adds extra information about the house, but it is not needed to identify which house we mean.

The main statement still works without it:

• Το σπίτι είναι πιο όμορφο απ’ όσο περίμενα.

The middle part simply adds description:

• from whose balcony the sea is visible

So the commas show that this is inserted, extra information.

Yes, it sounds somewhat formal or written, mainly because of του οποίου.

More conversational Greek would often prefer something simpler, such as:

• Το σπίτι, που έχει θέα στη θάλασσα από το μπαλκόνι του, είναι…
• Το σπίτι, από το μπαλκόνι του οποίου βλέπεις τη θάλασσα, είναι… depending on style and meaning

But the original sentence is perfectly correct and elegant. It is the kind of structure you might see in careful writing, descriptions, or higher-register speech.

You can understand it that way, but it is not natural English.

A literal breakdown is useful for grammar:

• από = from
• το μπαλκόνι = the balcony
• του οποίου = of which / whose
• φαίνεται η θάλασσα = the sea is visible / the sea can be seen

But in natural English, better translations are:

• from whose balcony the sea is visible
• from whose balcony you can see the sea
• whose balcony overlooks the sea depending on context

So the literal version is helpful for analysis, but not for good English style.