Learn Hardcore Spanish (Spain): Quiero instalar paneles solares en el tejado de mi casa. - I want to install solar panels on the roof of my house.

The verb form quiero already tells us the subject is yo (1st person singular).
Spanish usually omits subject pronouns unless you want to:
- Emphasize contrast: Yo quiero instalar paneles solares, pero ellos no.
- Clarify who you mean when it’s ambiguous.

So:

Quiero instalar paneles solares… ✅ (most natural)
Yo quiero instalar paneles solares… ✅ (correct, but sounds more emphatic in Spanish than in English)

Why is instalar in the infinitive? Could it be quiero que instalo?

After verbs of desire like querer, when the subject is the same for both verbs, Spanish uses the infinitive:

Quiero instalar… = I want to install…

The pattern is:

querer + infinitive when the same person both wants and does the action.

You cannot say quiero que instalo. That’s incorrect.

You use quiero que + subjunctive when someone else is going to do the action:

Quiero que instalen paneles solares en el tejado de mi casa.
I want them to install solar panels on the roof of my house.

So:

Quiero instalar… → I want to be the one installing.
Quiero que instalen… → I want someone else to install.

Why is it paneles solares and not solares paneles?

In Spanish, adjectives normally go after the noun:

paneles solares = solar panels
coche rojo = red car
casa grande = big house

So:

paneles solares ✅ (normal Spanish order)
solares paneles ❌ (sounds wrong/poetic at best)

Also, panel solar / paneles solares is the standard fixed expression in Spanish, just like solar panel(s) in English.

Why is paneles plural? Could I say Quiero instalar un panel solar?

The sentence assumes more than one panel, so it uses the plural:

paneles solares = solar panels

If you really mean just one panel, you can absolutely say:

Quiero instalar un panel solar en el tejado de mi casa.

So the number (singular/plural) works just like in English:

un panel solar = one solar panel
unos paneles solares / varios paneles solares = some/several solar panels

Why tejado and not techo? Aren’t both “roof”?

In Spain, there’s an important difference:

tejado = the outside part of the roof, visible from the street, where you’d put solar panels.
techo = the inside part you see from inside your house (the ceiling in English), or the structural roof in more general terms.

So, for solar panels in Spain:

en el tejado de mi casa ✅ (natural and precise)

Saying en el techo de mi casa in Spain sounds odd for this context, because people imagine the interior ceiling, not the external surface.

In much of Latin America, techo often covers both ideas (roof + ceiling), but the sentence you gave clearly uses Peninsular (Spain) usage.

Why is it en el tejado and not something like sobre el tejado or a el tejado?

En is the standard preposition for locations like on / in / at in Spanish, and it’s used very broadly:

en el tejado = literally on the roof here.

Alternatives:

sobre el tejado → literally on top of the roof. It’s possible, but sounds more physical/visual; in this sentence en el tejado is more usual.
a el tejado → becomes al tejado, but that normally implies movement to the roof, not location on it:
- Subo al tejado. = I go up to the roof.

So for “I want to install X on the roof”, en el tejado is the natural choice.

Why is it de mi casa and not en mi casa or de la mi casa?

Each option means something different:

de mi casa
- de indicates possession/belonging:
  el tejado de mi casa = the roof of my house.
- This is what you want here: whose roof it is.
en mi casa
- en indicates location:
  en mi casa = in my house / at my house.
- If you said Quiero instalar paneles solares en mi casa, it sounds more general: at my house, not necessarily specifying the roof.
de la mi casa ❌
- In modern standard Spanish you don’t put a definite article (la) before a possessive like mi.
- You say mi casa, not la mi casa.

So the natural structure is:

en el tejado (location) de mi casa (possession).

Why mi casa and not mía casa or la casa mía?

Spanish has two main types of possessives:

Weak/short possessives (used before the noun):
- mi casa, tu coche, su jardín, nuestra empresa…
- These are by far the most common in everyday speech.
Strong/long possessives (used after the noun or alone):
- la casa mía, el coche tuyo, el jardín suyo
- la mía, el tuyo, los suyos (when the noun is omitted)

In your sentence:

mi casa is the normal, neutral choice.
la casa mía is possible but sounds more expressive or literary, or like you’re contrasting:
- No la casa de mis padres, sino la casa mía.

You cannot say mía casa; the strong forms like mía don’t go before the noun.

Could I say Quiero poner paneles solares instead of Quiero instalar paneles solares? Is there a difference?

You can say both, but there’s a nuance:

instalar suggests a more technical/permanent installation, usually by a professional:
- instalar paneles solares, instalar una alarma, instalar un programa…
poner is more general: to put / to place. It doesn’t necessarily carry the technical/installation idea:
- poner un cuadro en la pared = to put up a picture on the wall.

In real speech, especially in Spain, people do sometimes say:

Quiero poner paneles solares en el tejado de mi casa.

It sounds a bit more colloquial.
Quiero instalar paneles solares… is slightly more formal/technical and fits very well with the idea of a solar-panel system.

Is Quiero instalar… polite? In English, “I want to…” can sound a bit direct.

In Spanish, Quiero + infinitive is less blunt than “I want to…” often feels in English. It’s very common and usually not rude.

However, if you want to sound softer or more polite (for example, talking to a salesperson or writing an email), you have options:

Me gustaría instalar paneles solares…
= I would like to install solar panels… (more polite/softer)
Querría instalar paneles solares…
Also softer, more tentative.

So:

Quiero instalar paneles solares en el tejado de mi casa. → neutral, normal.
Me gustaría instalar paneles solares en el tejado de mi casa. → a bit more polite/soft.