Thermal insulation in one day and without building works

Save on your bills with Smart Thermal Insulation. Minimise the amount of heat and cold you waste and improve the comfort of your home.

Calculate your ideal insulation

What is blown thermal insulation?

Blown thermal insulation is the cheapest and most effective solution for saving energy. Approximately 30-35% of heat loss or cold input in a house is produced by the walls, but thanks to this technique your home will gain in efficiency and comfort forever, since it does not need maintenance.

How is it installed?

Without building works

Blown thermal insulation is a very simple intervention. It can be carried out through the outside of the façade, or on the inside (without the need for scaffolding). It does not require planning permission.

Air chamber

This is the gap that separates the inside brick wall from the outside wall. If your house was built between 1960 and 2006, it is most likely to have a cavity.


A flat can be insulated in one day. The insulating material is injected through small holes in the wall, filling the cavity. It provides homogeneous insulation while preventing draughts - and it also insulates acoustically!

Advantages of thermal insulation with Iberdrola

Heat and cold escape from your home without you realising it, take the plunge and turn your house into an efficient home.

Thermal insulation calculator

1. Select home type

2. Select the size of your home

Choose the area that is closest to its actual size.

2. Select the size of your home

Choose the area that is closest to its actual size.

2. Select the size of your home

Choose the area that is closest to its actual size.

2. Select the size of your home

Choose the area that is closest to its actual size.

3. Does your house have an air chamber?

3. Does your house have an air chamber?

3. Does your house have an air chamber?

3. Does your house have an air chamber?

3. Does your house have an air chamber?

3. Does your house have an air chamber?

3. Does your house have an air chamber?

3. Does your house have an air chamber?

3. Does your house have an air chamber?

3. Does your house have an air chamber?

3. Does your house have an air chamber?

3. Does your house have an air chamber?

4. Your recommended thermal insulation

Ask for a quote and start saving

One of our qualified technicians will visit your home to provide you with a custom quote

Type of home: terraced house

Surface area: Up to m2

cm air chamber

(1) Estimated price for normal installation conditions and good accessibility.

4. We have other solutions for you

Blown-in thermal insulation requires an air gap, but thanks to our Smart solutions you can also achieve an efficient home and save on your bill. Find out which one is best for you:




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Any questions?

Here you'll find some of the most frequent questions, with their answers, in case they are helpful for you.

Thermal insulation is the set of materials and installation techniques that are applied to the parts of a construction that separate a heated space from the outside or from other spaces to reduce heat transmission between them.

The most common case is the insulation of buildings to minimise loss of heat in winter and to repel heat in summer.

Thermal insulation is the main, cheapest and most effective energy-saving measure. Thermal insulation is the perfect complement to electrification of heating and to overall achieve a drastic reduction in the carbon footprint. What's more, most thermal insulation also provides effective sound insulation, keeping bothersome noise out of the building.

Because 40 % of the energy consumed by Spanish households is used for heating and cooling.

In the coldest areas this percentage sometimes reaches 80%. 80% of the energy consumed by some homes is used to heat them!

There are many simple but effective ways to insulate your home, which can significantly reduce the amount of heat you lose while reducing your heating bills.

Any renovations and modernisation carried out on the home are a superb occasion for analysing energy efficiency and insulation: you'll gain in comfort, lower your bills and emissions and add to the value of your home.

Spain has set itself an objective within the National Integrated Energy and Climate Plan (PNIEC) to upgrade 1.2 million homes by 2030.

Roofs, walls, windows, doors and floors are the main areas where warm air will escape and cold air enter.

Although there is no "one-size-fits-all" solution, generally speaking, houses lose warmth as follows:

  • between 7 and 15% through the ground depending on the type of housing.
  • from 30 % to 35 % through walls and thermal bridges.
  • up to 25 % through doors, windows, seals, and cracks.
  • around 25 % through roofs and terraces.
Imagen aislamiento

Improving wall insulation is the quickest and most effective way to reduce your energy consumption in the home.

There are three main methods to improve thermal insulation for opaque enclosures: outside, inside and in the middle.

    From the outside, it's the most efficient way to reduce energy demand, with the External Thermal Insulation Composite System (ETICS) or ventilated façade. The drawback is that the project must tackle the entire building, it can take several weeks, and it is the most expensive solution. Insulation can be installed on the inside (lining), with multiple solutions existing on the market. The drawback is that it reduces the amount of living space in the home and does not deal with thermal bridges. If the home has double partition walls (double leaf façades, façades with air chamber) or false ceilings, insulation by blowing insulating material into these chambers is a quick, economical and effective technique. The drawback is that it can only be used if there is an air chamber. Like the facing shell method, it does not resolve the thermal bridge issue.

There are many ways to improve insulation with windows, from installing double glazing in metal-framed windows, with or without thermal bridge breaking, to triple glazed windows with low emissions treatments and PVC frames with excellent thermal efficiency. Depending on the climate, the orientation of the gap and your budget, you will always find a solution that will improve the energy efficiency of the home.

The first noticeable change in the home is comfort. It will stay warmer for longer in winter and cooler in summer. In winter, I will notice that the walls are not as cold as they used to be before I installed the insulation and that my home will feel far more comfortable. I will notice less difference in the temperatures between different parts of the rooms.

The heating/cooling system will start up less frequently, and I will notice fewer temperature variations. This will mean lower heating/cooling bills.

Improved insulation helps to prevent draughts, moisture and mould, improving living conditions and health.

If the home has double partition walls (double leaf façades, façades with air cavity) or false ceilings, insulation by blowing insulating material into these cavities is a quick, economical and effective technique.

The insulating material is blown into the air cavity, filling the entire cavity and providing homogeneous insulation while stopping draughts. And it also provides sound insulation!

The solution has been used for more than 30 years and is used widely in countries with a continental climate. In the United Kingdom, Belgium, France and Holland, millions of houses have been air cavity insulated.

Holes are made in the brick or in the partition wall and the insulation material is blown through. The holes are then carefully sealed so that there is no sign of the operation. Holes are made all over the façade so that the insulation covers the entire wall. The insulation completely fills the air gap, leaving a layer of insulation that not only insulates but also prevents outside air from coming through the air gap.

It can be done from either the outside or the inside. In apartments, in practically all cases it is done from the inside.

If you want to install blown cavity wall insulation in your home, you need to find out if there is an air cavity in your walls.

If your home was built after 1960 and before 2006, it most likely has air cavities. If it was built after 1979, it probably has some insulation, although it is probably insufficient.

If the wall sounds hollow when you bang on it, or if when you go close to the socket (without touching it) you notice air currents, then you have air cavities.

In any case, an Iberdrola partner can come to your home to see if there is an air cavity and measure its thickness to provide you with an estimate for blown cavity wall insulation.

No. It's a simple process. It takes just hours or a day to insulate a flat. In the case of a detached house, it can take one or two days to insulate.

The operation can be carried out from the inside or the outside, provided that there is a common electricity supply for the blower. In rooms with tiling, it is advisable to carry out the procedure from the outside if possible to avoid drilling holes in the tiles, although a very common option is to insulate the entire home except for the kitchen and bathrooms.

If the procedure is performed from the outside, it may be auxiliary equipment may be required.

The benefits of thermal insulation continue throughout the life of the building. It needs no maintenance and there are therefore no additional costs.

Thermal insulation will reduce the demand for energy in the home, which will put a smile on your face when you see your fuel bills are lower, year after year. The planet will thank you, too. What's more, it will improve your quality of life and provide sound insulation.

Currently Aislamiento Smart exclusively installs glass mineral wool since it is the optimal product in relation to its properties and cost.

Blown insulation can only be done once in a lifetime, so we are committed to doing it with the best product on the market.

Glass mineral wool is a product manufactured specifically to be blown (it is not waste or discarded from other processes), it is A1 fire retardant, non-hydrophilic and has excellent thermal properties. In addition, it can be installed via smaller drill holes than other materials. Plus, the glass mineral wool that we install has certifications from independent entities that attest to its properties, indoor air quality seal and stamps stating it poses to health risks. Furthermore, it is made using up to 80% recycled material.

There are several materials including wool (glass mineral wool or rock wool), cellulose, EPS and polyurethane.

Mineral wool and rock wool have similar insulating properties and both are a very good choice if the air gap is of sufficient size (from 4 or 5 cm gap thickness). Both are non-combustible, with A1 fire rating. They help to make buildings more fire resistant. Both are permeable to water vapour, which means that the building can breathe, allowing water vapour through the walls. Both are non-hygroscopic, so they do not absorb moisture. They also provide some sound insulation and are very durable, with a service life of more than 50 years.

In very small cavities, EPS has better coverage and is the optimal material for filling very small gaps. On the downside, it is more expensive and does not insulate from noise.

Cellulose has the advantage of being a recycled material, contributing to its sustainability, but nevertheless it must be treated with additives to make it fireproof, i.e., it does not spread flames, achieving a Class B rating as an insulating material. It is also treated so that it absorbs a minimum amount of water.

No. It is the most economical option for reducing the need for heat and cold in a home.

It costs between around €1000 and €1500 to insulate a flat. A single-family home around €2000 to €2500.

The thicker the chamber, the more insulating material is needed to fill it and the greater your savings on heating and air conditioning.

It's the ideal solution if you have air chambers and gives you the best return on each euro invested in insulation.

In apartments or small homes, it is highly recommended that several neighbours get together. This allows us to pass on the savings associated with treating several homes in the same block to the customers. This makes us more efficient in home visits and insulation, meaning we can offer a better price.

Each home is unique. For this reason, a home visit is necessary to inspect the cavity to check the condition, feasibility of the installation and potential for improvement.

All our estimates are made to measure and after a technician's visit, since it is impossible to assess from a distance and even more so taking into account the enormous variability inherent in architecture.

The surface area of the house to be insulated tells me how "big" the shelter to be placed will be, and the size of the cavity how "thick" that shelter will be.

To ease the initial outlay, Iberdrola has agreements with lenders that will allow you to finance it. That means you can pay for your installation while you save on your bills.

The amount will depend on the size of your home, the type of heating and the thickness of the cavity. In the case of a home with a gas boiler with an annual consumption of ¤550, saving 20% of the gas used for heating will reduce the annual bill by around ¤90 and prevent the emission of 240 kg of Co2 every year. If you have an oil-fired or LNG boiler, the emissions avoided will be higher.

The more you spend on heating your home, the bigger the potential savings and reduction of emissions.

If you also decide to upgrade your heating system, you can choose something less powerful, which will be kinder to the environment and make more savings.

If you have a false ceiling it can almost always be insulated. If you have air conditioning through ducts with the return without ducting, it should not be insulated. In all other cases, yes.

The larger the space above the false ceiling, the greater potential for gains there will be. We will also have to use more material to fill it, but the additional improvement will be worth the increased cost.

The ideal is to fill them completely. If the space is very large, more than 20cm, it may not be filled completely since the improvement will already be very significant without needing to fill it completely.

If the false ceiling is inclined (attic areas) it is necessary to fill it completely regardless of the space since it is the only way to guarantee that the placement of the material is correct.

These are one of the main points where heat escapes in winter and where heat enters in summer. Our technicians will advise you during the visit, but in almost all cases it should be the first point to improve.

If we have given you a quote for the façade and roof and you are not sure to what extent you wish to contract, the technician will advise you, but the general recommendation will be that we start the insulation with the roof (false ceiling or roof as the case may be).

The house may not start with the roof, but at Aislamiento Smart we do start improving efficiency from the top!

No. The glass mineral wool provides an acoustic improvement, but against airborne noises (voices in the street, cars), not against noises that are transmitted through the structure.

Usually not. The most common construction methods do not allow this. Only in exceptional cases, when we have documentation and know that it is feasible, do we isolate the party walls.

No. You can request a quote and then decide whether one, two, three, eight or all of them take up the offer. The decision will be individual and depending on the number contracted, the efficiency gain in the installation process is transferred in the form of a better price to the customers.

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Any more questions?

Contact us to assess whether the thermal insulation solution is suitable for your home.