Το Πιστοποιητικό Ενεργειακής Απόδοσης χρειάζεται ενεργειακή επιθεώρηση.

Because Πιστοποιητικό is a neuter singular noun.

In Greek, the definite article has to match the noun’s:

• gender
• number
• case

So:

• ο = masculine singular
• η = feminine singular
• το = neuter singular

Since the head noun is Πιστοποιητικό, the phrase begins with το Πιστοποιητικό.

They are in the genitive singular, because this part means something like of energy performance.

So the structure is:

• Πιστοποιητικό = certificate
• Ενεργειακής Απόδοσης = of energy performance

This is a very common Greek pattern: noun + genitive.

More specifically:

• απόδοση → απόδοσης in the genitive singular
• ενεργειακή → ενεργειακής so that it agrees with απόδοσης

So Greek is literally building:

certificate + of energy performance

It describes Απόδοσης, not Πιστοποιητικό.

That is an important point.

The phrase is grouped like this:

[Πιστοποιητικό] [Ενεργειακής Απόδοσης]

and inside the second part:

• Ενεργειακής modifies Απόδοσης

So it is not an energy certificate in the grammatical sense of ενεργειακό πιστοποιητικό.
It is a certificate of energy performance.

It looks passive to an English speaker, but here it is functioning with an active meaning: needs / requires.

The verb is χρειάζομαι, which is one of those Modern Greek verbs that often appears in middle/passive-looking forms but can still have an active sense.

So here:

• Το Πιστοποιητικό ... χρειάζεται ...
• = The certificate needs / requires ...

So although χρειάζεται has a form that resembles the passive, in this sentence it does not mean is needed.

It is the direct object of χρειάζεται, so it is in the accusative singular.

However, in this noun phrase, the accusative looks the same as the nominative:

• ενεργειακή = nominative/accusative feminine singular
• επιθεώρηση = nominative/accusative feminine singular

So even though the form does not visibly change, its function in the sentence is accusative.

Because Greek often leaves an indefinite direct object without an article, especially when the meaning is general.

So:

• χρειάζεται ενεργειακή επιθεώρηση
• = needs an energy inspection

You could also say:

• χρειάζεται μια ενεργειακή επιθεώρηση

Adding μια makes the indefiniteness more explicit, similar to English an.
Without μια, the sentence is still completely natural.

Yes, in other contexts it can.

For example:

• Χρειάζεται ενεργειακή επιθεώρηση.

Without a clear subject before the verb, this could mean:

• An energy inspection is needed
• or more loosely An energy inspection is required

But in your sentence, the subject is clearly stated:

• Το Πιστοποιητικό Ενεργειακής Απόδοσης χρειάζεται ...

So here the meaning is:

• The Energy Performance Certificate needs / requires ...

Context tells you which meaning is intended.

Normally, Greek does not capitalize every important word the way English titles often do.

But here Πιστοποιητικό Ενεργειακής Απόδοσης is being treated as the official name of a document. In formal or administrative language, this kind of capitalization is common.

So the capitals are not mainly about grammar; they are about style and official terminology.

In less formal writing, you may also see:

• πιστοποιητικό ενεργειακής απόδοσης

Both can occur, depending on context and house style.

Yes, Greek word order is more flexible than English word order.

The neutral, straightforward order here is:

• subject + verb + object
• Το Πιστοποιητικό Ενεργειακής Απόδοσης χρειάζεται ενεργειακή επιθεώρηση.

But Greek can move parts around for emphasis, focus, or style.

For example, putting ενεργειακή επιθεώρηση earlier could emphasize what is needed.

That said, the original order is the most neutral and easiest for learners to understand.

Yes. It is a standard official term, not just a random combination of words.

In Greece, this is the established name for the Energy Performance Certificate, and it is often abbreviated as:

• ΠΕΑ

So learners should treat Πιστοποιητικό Ενεργειακής Απόδοσης as a set administrative phrase worth memorizing as a whole.

No.

Greek does not require an extra subject pronoun when the subject is already stated.

Here the subject is already the full noun phrase:

• Το Πιστοποιητικό Ενεργειακής Απόδοσης

So adding a separate pronoun would be unnecessary.

In fact, Greek often omits subject pronouns even when the subject is only understood from the verb ending. Here, because the noun phrase is present, the sentence is already complete and clear.