Spíš vypnu vytápění.

Here spíš is an adverb, a shortened, more informal form of spíše. In this sentence it means something like rather, instead, or more likely.

It is not the verb form from spát here, even though the spelling is the same. Czech often relies on context to distinguish them.

• Ty spíš. = You are sleeping / You sleep.
• Spíš vypnu vytápění. = I’d rather / I’ll probably switch off the heating instead.

So yes, the form is identical, but the function is different.

Because Czech usually omits subject pronouns when they are clear from the verb ending.

The verb vypnu already means I will switch off:

• -u here marks 1st person singular

So já is unnecessary unless you want extra emphasis or contrast:

• Já spíš vypnu vytápění. = I’ll turn off the heating instead (with emphasis on I)

This is very normal in Czech.

This is because vypnout is a perfective verb.

In Czech, perfective verbs do not have a normal present meaning for ongoing actions. Their present-tense forms usually refer to a future completed action.

So:

• vypínám = I am switching off / I switch off
  imperfective
• vypnu = I will switch off
  perfective

So vypnu is grammatically a present-tense form, but in meaning it is future.

The dictionary form is vypnout.

A few forms are:

• vypnout = to switch off / turn off
• vypnu = I will switch off
• vypneš = you will switch off
• vypne = he/she/it will switch off

So when you look up vypnu, you need to search for vypnout.

Vytápění is a noun, not a finite verb. It means heating, especially in the sense of space heating or a heating system/process.

It comes from the verb vytápět = to heat a building/room.

So vytápění can mean things like:

• heating in general
• the heating system
• the process of heating a space

In everyday home situations, Czech speakers often also use topení, which can sound a bit more everyday and less technical.

Because here it is a neuter noun, and its accusative singular form is the same as its nominative singular form.

So:

• vytápění = nominative singular
• vytápění = accusative singular

That is why the direct object still appears as vytápění.

This is common with many neuter nouns, especially verbal nouns ending in -ní or -tí.

Czech word order is much more flexible than English word order. Putting spíš first gives it scope over the whole sentence and makes the sentence sound like:

• Rather, I’ll turn off the heating
• I’ll probably turn off the heating instead

So Spíš vypnu vytápění is natural as a way to frame the whole statement.

Other word orders are possible, but they change emphasis:

• Spíš vypnu vytápění. = neutral, sentence-level rather/instead
• Vytápění spíš vypnu. = stronger focus on the heating
• Spíše vypnu vytápění. = same idea, but more formal because of spíše

Not exactly, though they can overlap in translation.

• radši / raději expresses preference very clearly: I’d rather
• spíš / spíše often means rather, more likely, instead, or on the whole

So:

• Radši vypnu vytápění. = I’d rather turn off the heating.
• Spíš vypnu vytápění. = I’ll probably / rather turn off the heating instead.

In many contexts, radši sounds more clearly like a personal preference, while spíš can sound a bit more tentative or comparative.

Spíš is more informal and common in everyday speech. The fuller form spíše is more neutral or slightly more formal.

So these are close in meaning:

• Spíš vypnu vytápění.
• Spíše vypnu vytápění.

The first sounds more conversational.

Often, yes.

In everyday conversation about a home or apartment, many speakers would naturally say:

• Spíš vypnu topení.

Topení is very common for the heating in ordinary daily speech.
Vytápění is also correct, but it can sound a bit broader, more technical, or more system-oriented.

So both work, but they have a slightly different feel:

• topení = everyday, practical
• vytápění = a bit more formal/technical

Yes. Very often spíš implies instead of something else, even if that other option is not explicitly mentioned.

So Spíš vypnu vytápění can suggest something like:

• instead of opening the window
• instead of lowering the thermostat
• instead of doing something more complicated

That unstated comparison is a very natural part of how spíš / spíše works in Czech.