Η ενεργειακή επιθεώρηση ελέγχει την αντικατάσταση κουφωμάτων.

Because this is the subject of the sentence, so it is in the nominative case.

• η = the feminine singular nominative article
• ενεργειακή = energy / energetic-related, feminine singular nominative
• επιθεώρηση = inspection, a feminine noun

The adjective ενεργειακή has to agree with επιθεώρηση in:

• gender: feminine
• number: singular
• case: nominative

So Greek is showing grammatical agreement very clearly here.

Because την αντικατάσταση is the direct object of the verb ελέγχει.

Greek marks this with the accusative case:

• η επιθεώρηση = nominative, subject
• την αντικατάσταση = accusative, direct object

So the sentence structure is:

• Η ενεργειακή επιθεώρηση = the energy inspection
• ελέγχει = checks
• την αντικατάσταση κουφωμάτων = the replacement of frames/windows

A useful point: with many feminine nouns like αντικατάσταση, the noun itself often looks the same in nominative and accusative singular, so the article is what makes the case most obvious:

• η αντικατάσταση
• την αντικατάσταση

ελέγχει is the 3rd person singular present active form of ελέγχω = I check / inspect / verify.

So ελέγχει means:

• he/she/it checks
• in this sentence: it checks, referring to η ενεργειακή επιθεώρηση

Greek usually does not need a separate subject pronoun like it, because the verb ending already shows the person and number.

Because it depends on αντικατάσταση and means replacement of frames/windows.

In Greek, nouns like αντικατάσταση often take a genitive to show what is being replaced:

• αντικατάσταση κουφωμάτων = replacement of frames/windows

Here:

• κουφωμάτων = genitive plural
• base form: κούφωμα = frame / window-door unit
• plural nominative/accusative: κουφώματα
• genitive plural: κουφωμάτων

So Greek expresses this idea with a genitive where English often uses of.

Not exactly. κουφώματα is a technical building term.

It often refers to:

• frames
• window and door frames
• sometimes the whole installed window/door unit, depending on context

So in construction or energy-efficiency contexts, αντικατάσταση κουφωμάτων often means something like:

• replacement of window/door frames
• or more naturally in English, replacement of windows and doors, if that is what the context implies

A learner should know that the Greek word is often broader and more technical than plain English windows.

Greek can omit the article in this kind of phrase, especially in a general, technical, or administrative style.

So:

• την αντικατάσταση κουφωμάτων = replacement of frames/windows, in a general or category-like sense
• την αντικατάσταση των κουφωμάτων = replacement of the frames/windows, more specific

Both are possible, but they do not feel exactly the same.

Without the article, the phrase can sound a bit more like:

• window replacement
• replacement of frames/windows as a type of work

With των, it more clearly points to specific frames/windows already known from context.

Yes. This is a very normal subject–verb–object order:

• Η ενεργειακή επιθεώρηση = subject
• ελέγχει = verb
• την αντικατάσταση κουφωμάτων = object

Greek word order is more flexible than English because case endings and articles help show each word’s role. But this sentence uses a straightforward, neutral order.

For emphasis, Greek could reorder parts of the sentence, but this version is the most basic and natural for a learner to recognize.

Yes, Greek adjectives can often appear either before or after the noun.

So you may see:

• η ενεργειακή επιθεώρηση
• η επιθεώρηση η ενεργειακή — this exact version is not the normal neutral choice here
• more naturally as an alternative adjective placement in other cases: η επιθεώρηση ενεργειακής απόδοσης is a different construction altogether

In this sentence, η ενεργειακή επιθεώρηση is the normal and natural phrasing.

For learners, the important point is that ενεργειακή agrees with επιθεώρηση, no matter where it appears.

A rough pronunciation guide is:

ee en-er-yee-ah-KEE ep-ee-theh-O-ree-see el-EHng-khee teen an-dee-kah-TAH-stah-see koo-foh-MAH-ton

A few useful pronunciation notes:

• η / ι / υ / ει / οι are all pronounced like ee
• γχ in ελέγχει is pronounced roughly like ng-kh or ngh, not like English ch
• the stress marks matter:
  • ενεργειακή
  • επιθεώρηση
  • ελέγχει
  • αντικατάσταση
  • κουφωμάτων

So the stressed syllables should be pronounced more strongly.