Treevia standard vs market standard – what do you really get for the price?
You buy a modular house for PLN 700,000. You sign the contract, pay the deposit. Then it turns out the foundation costs an extra PLN 30,000, heat recovery ventilation another 20,000, underfloor heating another 30,000. You end up paying PLN 850,000 – and you do not even have a better house than one that cost PLN 830,000 with everything included.
This is not a made-up scenario. This is the standard in the Polish modular house market.
The problem: "price from..." is not the final price
Most modular house manufacturers quote a price in basic developer standard. Sounds specific, but in practice it means:
- ❌ No foundation
- ❌ No heat recovery ventilation (mechanical ventilation with heat recovery)
- ❌ No underfloor heating
- ❌ Often no specific window parameters
- ❌ No guaranteed U-value
The customer sees an attractive price, makes a decision, then adds extra items. The final amount grows by PLN 65,000–90,000 above the quoted price.
What does Treevia ALL-IN include?
In the ALL-IN variant of the BARN 120 model (123.8 m², ground floor + attic) for PLN 828,608 net (~PLN 895,000 gross with 8% VAT), the customer receives:
Element — Treevia ALL-IN — Market standard
Foundation — ✅ Reinforced concrete slab 28 cm, XPS 200 mm — ❌ Extra cost ~PLN 30,000
Heat recovery — ✅ Ventilation with heat recovery — ❌ Option +PLN 15–25,000
Underfloor heating — ✅ Whole house — ❌ Option +PLN 20–35,000
Architectural project — ✅ Included in ALL-IN — ✅ Often included
Transport — ✅ Up to 100 km included — Varies
Triple-glazed windows — ✅ Uw ≤ 0.9 W/(m²K) — Depends on model
Installation shaft — ✅ 4–6 cm — ❌ None
Structural warranty — ✅ 30 years — Varies – usually 10–15 years
Thermal parameters – where the real difference lies
Price is one thing, but you buy a house for 30+ years. Thermal parameters determine heating bills for that entire period.
External wall U-value:
- Treevia: U = 0.15 W/(m²K) – confirmed by calculations
- Market standard: ~0.18–0.20 W/(m²K) – at the limit of WT 2021
A 25% difference in heat loss through the wall. For a 120–130 m² house, that is an estimated PLN 1,000–2,500 per year less on heating. Over 30 years: PLN 30,000–75,000 in savings – without accounting for energy price increases.
Water vapour condensation:
- Treevia: zero condensation in all layers (ubakus calculations: 90 days, −20°C/80% outside, +22°C inside)
- Market standard: data usually not published
Phase shift:
- Treevia: 11 hours – outdoor heat reaches the interior with a multi-hour delay
- Market standard: manufacturers typically do not provide this parameter
Amplitude damping:
- Treevia: 17× – 30°C swing outside = ~1.5°C inside
- Market standard: data not published
Wall: 12 layers vs 8 layers
Wall construction is the fundamental difference between Treevia and market standard.
Treevia (from outside):
Cladding → ventilated gap 30 mm → Dörken Delta-Vent S+ membrane → wool 75 mm → OSB → wool 150 mm+ (C24) → OSB → wool 50 mm → PE film → OSB → shaft 4–6 cm → plasterboard
Market standard (typical):
Base render → membrane → wool 180 mm → wood-based board → wool 50 mm → wood-based board → PE film → plasterboard
Key differences:
- Ventilated façade – Treevia has a 30 mm gap protecting the membrane; the market often applies render directly on the membrane
- Three insulation layers instead of two – eliminating thermal bridges
- Installation shaft – Treevia: servicing without breaking; market: installations in the wall
- Premium membrane – Dörken Delta-Vent S+ vs standard diffusion membrane
Summer comfort – the parameter nobody talks about
With increasingly hot summers (35–40°C), summer thermal comfort is becoming as important as winter.
The 11-hour phase shift in the Treevia wall means heat from 2:00 PM reaches the interior at 1:00 AM – when it is already cool outside. The house naturally "buffers" itself without air conditioning.
No air conditioning means savings:
- AC purchase cost: PLN 8,000–15,000
- Running cost: PLN 1,000–2,000/year
- Over 30 years: PLN 38,000–75,000
The market standard does not publish phase shift and amplitude damping data – because these parameters do not look favourable with a thinner wall.
Installation shaft – why you will be grateful in 20 years
In a standard modular house, electrical and plumbing installations run inside the structural wall. Today that is no problem. But in 15–20 years, when replacement is needed:
- House without shaft: wall-breaking → insulation damage → PE film breach → PLN 20–50,000 + weeks of renovation
- Treevia house: open shaft → replace → close → a few thousand PLN + a few hours
A pierced vapour barrier membrane will never be as airtight as the original. Every break permanently worsens the house's thermal performance.
Real cost comparison – ~120 m² house
Let us compare on concrete numbers:
Treevia BARN 120 ALL-IN: PLN 828,608 net (~PLN 895,000 gross)
- Foundation ✅
- Heat recovery ✅
- Underfloor heating ✅
- Project ✅
- Transport up to 100 km ✅
- U = 0.15, shaft, ventilated façade
Typical market house ~120 m², developer standard: ~PLN 540–650,000 gross
- \+ foundation: ~PLN 30,000
- \+ heat recovery: ~PLN 15–25,000
- \+ underfloor heating: ~PLN 20–35,000
- = PLN 605–740,000 minimum, but with worse parameters
Price difference: PLN 155–290,000 in favour of the market.
But: energy savings PLN 30–75,000 + no AC PLN 38–75,000 + no shaft renovation costs PLN 20–50,000 = PLN 88–200,000 payback over 30 years.
Realistically, the Treevia ALL-IN house is more expensive by tens of thousands PLN, but delivers measurably better quality of life and lower operating costs for decades.
Summary
When buying a modular house, do not compare "from..." prices. Compare:
- What is included – foundation, heat recovery, underfloor heating, transport
- Thermal parameters – wall U-value, condensation, phase shift
- Wall construction – how many layers, which membrane, is there a shaft
- 30-year perspective – heating costs, installation servicing, façade durability
The market standard meets the norm. Treevia exceeds it by 25% – and that shows in heating bills, summer comfort, and ease of servicing in 20 years.