Vacuum insulation panel (VIP)
Evacuated, gas-tight insulation board that is several times better per thickness than conventional insulation, but cannot be cut or drilled on site.
A vákuová izolačná doska, known in English as a vacuum insulation panel (VIP), is an insulation board whose core has had almost all of its air removed and is then sealed inside a gas-tight envelope. The core is usually a pressed, very fine silica powder. Ordinary insulation slows heat flow by trapping still air, and gas molecules carry much of the heat through it. Removing the gas slows heat flow far more, so the performance comes from the vacuum rather than from the core material itself. The principle is similar to a vacuum flask.
The envelope is a multilayer foil that has to stay intact for the whole life of the panel. Protective facings, such as foam, laminate, aluminium or wood-fibre board, are often bonded to the outside to guard the foil against mechanical damage. The panel is thin, rigid and factory-made. It arrives as a finished product and is not assembled on the building.
How is a VIP different from conventional and aerogel insulation?
A VIP gives the most insulation for a given thickness of any common building product, which is why it is considered where thickness is the real constraint. Conventional materials such as EPS/XPS insulation and mineral wool insulation rely on still air held in a fibre or foam structure. A VIP removes the air instead. Aerogel insulation is the other high-performance option, and the two are often confused, so the table below sets them side by side.
| Property | VIP | Conventional (EPS, XPS, mineral wool) | Aerogel insulation |
|---|---|---|---|
| Performance per unit thickness | Several times better than conventional insulation | Baseline | High, generally below a VIP |
| Cutting on site | Not possible | Routine | Generally possible, depending on the product |
| Tolerance to puncture | Low, a nail or drill destroys the vacuum | Good | Moderate, depending on the product |
| Edge losses between boards | Significant, must be designed out | Handled by standard detailing | Must be detailed, depending on the product |
| Price | Far above EPS or mineral wool | Low | High |
In short, a VIP buys thickness at a high price and under strict handling rules. Conventional insulation delivers general performance cheaply and forgivingly. Aerogel sits between the two for many jobs, although its exact place depends on the product and the detail.
Where does a VIP make sense in a house?
A VIP earns its place where the available thickness, not the material budget, is the limit. In Slovak practice this usually means one of the following situations.
- Terrace thresholds over heated rooms, where the floor build-up has to stay low so the door sill still clears the terrace surface.
- Window reveals (ostenie okna), where a thin layer can insulate the reveal without shrinking the window opening.
- Balcony floors, where insulation from below is only possible if the available depth allows it. For balconies the connection itself is usually the bigger issue, and a structural thermal break is the more common answer.
- Renovations of listed facades (pamiatkovo chránená budova), where the outer appearance is fixed and the wall build-up cannot grow much. Any change should be agreed with the Pamiatkový úrad Slovenskej republiky before work starts.
Outside these cases a VIP is rarely the right answer for a whole house. A standard envelope made of conventional insulation is cheaper, easier to build and more forgiving of site conditions.
What are the honest limits of a VIP on site?
Most problems with VIPs come from handling on site, not from the panel itself. Four limits matter most.
Can a VIP be cut or drilled?
No. Cutting, drilling or notching a VIP breaks the envelope and destroys the vacuum. Every panel has to be ordered to its final size, using dimensions measured on the building and checked before production. If a wall is out of square or a reveal differs from the drawing, the panel will not fit, and there is no reliable way to correct it on site.
What happens when a panel is punctured?
A nail, screw, anchor or sharp tool can puncture the envelope. Once air enters the core, the panel loses most of its advantage, and the damage often cannot be seen by eye. Fixings and mounting aids must be planned so that nothing penetrates the panel, and the panels must be protected during delivery, storage and installation.
How do edges and joints affect performance?
The gaps between panels, the envelope edges and any metal fixings are weak points. Even small gaps, or a conductive part bridging the joint, can cancel much of the gain. This is the same mechanism described in the general entry on the thermal bridge: heat finds the easiest path, and at the edges of a VIP that path is through the joint. The joints therefore need the same care as the panels.
Is the price justified?
A VIP costs far more per square metre than EPS or mineral wool. Custom sizes add cost and time, because each panel is made to order. The price is only justified where thickness is the decisive constraint, and it should be compared with the cost of the alternative, such as a thicker conventional layer where the building allows one.
How should a VIP be planned so it keeps its performance?
Planning is what separates a working VIP detail from an expensive disappointment. The table below lists the decisions that have to be made before the first panel is ordered.
| Step | What to decide | Why it matters |
|---|---|---|
| Measure | Final dimensions of each opening and surface, checked on the building | Panels cannot be trimmed on site |
| Layout | Panel sizes and joint positions, using standard sizes where possible | Custom sizes cost more and take longer |
| Fixings | A mounting method that avoids penetrating the panel | A puncture loses most of the performance |
| Edges | Edge detail and overlaps that limit bridging between panels | Edge losses reduce the real performance |
| Protection | Facing and handling plan for delivery and installation | Damage often happens before the wall is closed |
| Verification | Thermal calculation using the actual joint and edge details | Nominal panel values ignore the edges |
The most reliable input is the supplier's documentation for the specific panel. VIPs are not covered by a harmonised product standard, so their performance is usually described in a European Technical Assessment (ETA). Ask the supplier for it early, and confirm with the building authority that the detail is acceptable before construction begins.
What should a client know before choosing a VIP?
A VIP is a targeted solution, not a general upgrade. It buys thickness at a high price, leaves little room for change on site, and depends on a detail that is fixed before construction starts. If the same thermal result can be reached with a thicker conventional layer, that is usually the better choice. If it cannot, a VIP is worth a detailed design study, the supplier's ETA and a thermal check of the actual edges.
Frequently asked questions
- Can a vacuum insulation panel be cut to fit on site?
- No. Cutting, drilling or notching breaks the envelope and destroys the vacuum, so every panel must be ordered to its final size from measurements taken on the building. Any dimensional error has to be caught before production.
- What happens if a nail goes through a VIP?
- The vacuum is lost and the panel loses most of the performance it was chosen for. The damage often cannot be seen, so fixings, storage and handling must be planned to prevent it.
- Are VIPs worth the extra cost for a whole house?
- Rarely. Their price is far above EPS or mineral wool, and their main advantage is thickness. Where thickness is not the limit, conventional insulation usually gives the better result for the money.
- Can a VIP be used on a listed building facade?
- It can be considered where the wall build-up is limited, but the change must be agreed with the Monuments Board of the Slovak Republic before work starts. The edges and fixings need the same careful check as any other VIP detail.
- How do edge losses between VIP panels affect the result?
- Gaps, overlaps and metal fixings between panels create thermal bridges that can pull the real performance well below the nominal panel value. The joints need to be designed as carefully as the panels themselves.
- Is a VIP the same as aerogel insulation?
- No. Both are high-performance materials, but a VIP is a sealed, evacuated board that cannot be cut on site, while aerogel insulation is a different material that is generally easier to work with. The comparison table in the article sets out the differences.