Why insulation matters more in a second home than in your main residence

The second home paradox: "it's just a holiday house"

I've been installing windows on the Costa Brava and across the Empordà region for over 20 years. And there's one phrase I hear constantly when I visit second homes: "Just put in something basic, we don't actually live here." I get it. It sounds logical. If you only come for a month in summer and the odd weekend, why invest in good insulation?

Well, precisely because of that. Because you don't live there. Because that house sits closed for 10 months a year with no ventilation, no heating and nobody opening a window in the morning. And believe me: a house that's been shut for months suffers far more than one that's lived in. I've seen hundreds of second homes with serious damp, condensation, mould and deterioration problems — problems that in many cases could have been avoided with decent windows.

This article is my personal opinion, based on what I see every week on site. It's not a sales pitch or a technical guide. It's what I think after two decades of replacing windows in houses that spend more time empty than occupied.

Damp in a closed house: the problem nobody sees until it's too late

An occupied home has a natural ventilation cycle. Every morning you open windows, dry air comes in, the humid night air goes out. You turn on the heating, cook, run the washing machine — all of that moves air around and regulates humidity. In a second home, none of that happens. The ambient moisture stays inside, building up week after week, month after month.

On the Costa Brava the problem is even worse. We're in an area with high relative humidity all year round, especially in winter. When a house is shut up with no heating, the walls and glass cool below the dew point. The result? Condensation. Water droplets on the glass, damp patches in the corners, mould behind the furniture. I've walked into flats in Roses, Platja d'Aro and Lloret where the smell of damp hit you the moment you opened the door.

With well-insulated windows — PVC with double or triple low-emissivity glazing — the interior surface temperature of the glass stays higher. That means the dew point isn't reached as easily and condensation drops dramatically. It's not magic, it's physics. A single pane goes ice-cold in winter and streams with water. Low-e double glazing keeps the interior surface warm and dry.

Airtightness: when nobody's there to ventilate, infiltration takes over

In your main home, if you have a window that doesn't close perfectly, it's no big deal — you ventilate daily, the heating compensates for losses and the air renews naturally. But in a second home closed for months, every gap is an entry point for damp, dust, insects and cold that builds up with no one to deal with it.

A poorly sealed window in an empty house causes:

• Cold draughts that cool interior walls and encourage condensation
• Rainwater ingress during storms — especially on the Costa Brava, where easterly storms are violent
• Dust and dirt that settle over months, ageing curtains, furniture and paintwork
• Insects and small animals getting in through deteriorated seals — I've found all sorts when opening old windows

Arriving on a Friday to find the house at 8 degrees: an experience every owner knows

If you own a second home you know exactly what I'm talking about. You arrive on a Friday evening in February after weeks without setting foot in the house. You open the door and you're met by a damp, bone-chilling cold. You switch on an electric heater, a fan heater, whatever you have. And two hours later the house is still cold. The walls are freezing, the floor is freezing, everything is cold. The heater warms the air around it but can't bring the house up to temperature.

Why? Because the windows are letting heat escape as fast as you generate it. With aluminium windows without thermal break — which is what most 70s, 80s and 90s apartments on the Costa Brava have — you're heating the street. The heat from your radiator goes out through the windows, through the roller shutter boxes, through the joints. It's like trying to fill a bath with the plug out.

With PVC windows and low-e double glazing, the house retains heat. You switch on the heating and within 30–40 minutes you feel the difference. The walls don't cool down as much because the heat doesn't escape, and that feeling of comfort arrives much sooner. That weekend that was going to start shivering on the sofa under a blanket becomes: arrive, turn on the heating and get comfortable in under an hour. That's priceless.

Security: an empty house needs windows that don't invite break-ins

I won't go into too much detail here because we've already written a full guide to windows for second homes covering security in depth. But I do want to say one thing: an old aluminium window with a basic catch can be opened with a screwdriver in 30 seconds. I've seen it. I know because people call me to replace windows after burglaries.

Quality PVC windows come with multi-point locking hardware and anti-lever mushroom cams as standard. You can add a lockable handle and P2A laminated glass. A window like that can't be opened with a screwdriver. It can't be levered open. And if you break the glass, the fragments stay bonded to the interlayer so you can't reach through to turn the handle. For a house that's empty 10 months a year, this is essential.

Zero maintenance: the advantage nobody mentions

A timber window in a second home is a disaster waiting to happen. Wood needs maintenance: sanding, varnishing, painting. If the house is closed and you don't look after it, the wood swells with damp, the paint peels, the seals deteriorate. Within 5–6 years you have a window that doesn't close properly, looks tired and needs an expensive restoration. On the Costa Brava, with the salt air, deterioration is even faster.

PVC needs absolutely nothing. No paint, no varnish, no sanding, no anti-corrosion treatment. A wipe with a damp cloth once a year when you come in summer and that's it. After 15 years it still looks the same as day one. For a property you don't use daily, that difference is huge. It's the difference between arriving and enjoying, or arriving and having to repair. See our full PVC vs aluminium comparison for all the details.

The 7 real benefits of good insulation in your second home

Let me summarise what I've been explaining in a clear list, because I think it's worth seeing everything together:

1. No condensation or damp — well-insulated windows keep the interior glass surface above the dew point. You arrive after months away and there are no droplets, no stains, no musty smell.
2. The house warms up fast — because it retains heat, the heating takes effect in minutes, not hours. That first winter Friday is a completely different experience.
3. No water or air infiltration — a window with triple seals and good installation protects the house from easterly storms even when you're not there.
4. Real security — multi-point hardware and laminated glass. A window that can't be opened with a screwdriver.
5. Zero maintenance — you don't have to do anything. No sanding, no painting, no treating. Perfect for a house you don't visit for months.
6. Heating savings — when you do use the house, you'll spend far less getting it warm. The window investment pays for itself bit by bit with every weekend you spend there.
7. Property value — good windows add real value to the property. If you ever sell or rent, it's a genuine selling point, especially for international buyers who place a high value on insulation.

If you look at this list objectively, you'll realise that most of these benefits are more relevant for an empty house than an occupied one. In your main home you ventilate, heat, maintain and keep an eye on things every day. In your second home you do none of that. And that's precisely why it needs better windows.

The Costa Brava: the perfect case study

It's no coincidence I'm writing this from Girona. The Costa Brava combines every factor that makes insulation critical in second homes: high humidity year-round, salt air on the seafront, violent easterly storms, and a huge stock of holiday housing built in the 70s, 80s and 90s with basic aluminium windows.

I've installed windows in apartments in Roses where salt had corroded the hardware beyond use. In villas in Begur where damp had caused black mould in every corner. In flats in Lloret where noise from the tourist area made sleep impossible with the old windows. In every case, switching to PVC with good glazing completely transformed the experience of using that second home.

If you have a second home on the Costa Brava and you're thinking about replacing the windows, get in touch — no obligation. We measure up when you can visit, manufacture in 3–4 weeks and coordinate the installation in a single day.

Frequently asked questions

Is it worth investing in good windows if I only use the house one month a year?

Yes, and precisely for that reason. A house closed for 11 months suffers more than one that's lived in — damp builds up, infiltration damages the property and every time you arrive you need hours to warm it up. With good windows you protect the house all 12 months and enjoy the days you're there much more.

Do PVC windows withstand the Costa Brava salt air?

PVC is immune to salt. It doesn't corrode, doesn't oxidise and needs no treatment. It's the ideal material for seafront properties. Standard aluminium corrodes and the hardware seizes up if you don't maintain it regularly — which is difficult in a house you don't visit for months.

Can I schedule the installation for a weekend I'm visiting?

Yes, we do it all the time with clients from Barcelona, France and northern Europe. We measure when you can visit, manufacture in 3–4 weeks and install in a single day coordinated with you. Many clients use a bank holiday or a Friday for the installation.

How much difference does it make to the heating bill?

It depends on your current windows, but the average is a 30–40% saving. In a second home where you're heating from zero every time you arrive, the difference is even more noticeable: the house reaches a comfortable temperature much sooner and holds it longer.

Do you have experience with apartment buildings on the coast?

Yes, we've done entire buildings in areas like Palamós, Platja d'Aro and Sant Feliu. We offer volume discounts and coordinate the installation flat by flat to minimise disruption.