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Energy-efficient timber houses start with the right structure
Energy performance

Energy-efficient timber houses start with the right structure

ZTC adapts timber structures to project energy requirements, insulation, airtightness and assembly quality.

ZTC experience and production facts

35+

years of experience

400+

completed projects

14

European countries

±1 mm

CNC precision

Technical energy performance indicators

ZTC timber structures can be designed for strong thermal performance, but the final result depends on the whole building — not wall thickness alone.

Wall U-value
0.12–0.15 W/m²K

Possible depending on construction, insulation and project requirements.

Airtightness
n50 < 0.6

Achievable with quality production, membranes and precise assembly.

Wall thickness
250–400 mm

Depends on insulation layer and structural solution.

What ZTC covers and what the project team reviews

  • ZTC provides the timber structure, insulation and membranes according to scope.
  • Windows, ventilation, heating and building form must be reviewed with architects and engineers.
  • A+ class depends on the whole building, not wall thickness alone.

An energy audit is usually carried out during the design stage to compare solutions before production and assembly.

What clients say about working with ZTC

Google reviews highlight structural quality and energy performance delivery.

Google review

We are Premium Living AS in Norway and built two houses with this company. We were very satisfied. We sold the last project 2 years ago when I write this review, and the first house was built 4 years ago. With both houses, the production, planning and timing all went smooth and well organised. Right now, all three buyers are pleased, and we haven't received a single complaint about flaws or even blemishes. Even during the Covid lockdowns there was no doubt that our investments and cooperation with ZTC were solid. We recommend, and anyone that has questions can ask ZTC for our reference.

Google review

ZTC built my house in 2012, and they have done some reclamation work in two periods since then. Only positive experiences with ZTC! Good quality of workmanship and customer support.

Review

We are the small clients of ZTC (because of small house for small kids) but that didn't change the amazing attitude to us and our deal from this amazing company! Even with the smallest business deals ZTC works with perfect attitude with all of clients. Professional, fast, with amazing surprises (!!!) which made us and our clients see and welcome the product with sparkling eyes! We just want to say you - THANK YOU! We wish you all the best! And the quality of kids house is really amazing!

Linda B.

ZTC technical reference points

U-value

Depending on construction, approximately 0.12–0.15 W/m²K is possible.

Airtightness

Quality structures can achieve n50 < 0.6.

Precise production

CNC precision of ±1 mm helps reduce assembly error risk.

Factory production

Panels are prepared in controlled conditions in the ZTC factory in Latvia.

A+ class and energy audit

A+ energy performance depends on the whole building — structure, windows, ventilation, heating and form. ZTC provides the timber structure and panel solution, while the energy audit result is defined during design together with architects and engineers. This helps choose scope before production.

Frequently asked questions

Questions about U-value, n50, A+ class, energy audit and timber structure solutions.

Standard wall U-values are Comfort 0.167, Premium 0.136 and Lux 0.100 W/m²K.

The specified U-value depends on the complete wall build-up agreed for the project, including layers installed on site. Whole-building energy performance also depends on windows, junctions, airtightness and building services. Your design team coordinates these with the project’s energy assessor.

The n50 value describes building airtightness. In quality constructions it is possible to achieve n50 below 0.6, which is important for energy-efficient buildings.

The final EPC rating depends on the complete building specification and is determined by an accredited assessor for the project.

Insulation, windows, airtightness, heating, ventilation and renewables all affect the result. The project’s accredited assessor determines the final EPC rating from the full specification. ZTC panels can support the agreed energy target, but a structural package alone cannot guarantee an EPC rating. Your design team should coordinate the full specification with the assessor.

Energy calculations are prepared during the design stage, before the panel specifications are finalised, and updated for the completed building.

The client or design team appoints a qualified assessor. Agree responsibility early so the calculations can guide the insulation, windows, airtightness, heating, ventilation and any renewables before manufacture.

Yes. ZTC manufactures timber frame panels in Latvia and provides transport and on-site assembly in the UK according to the agreed project scope. Your local architect or project team is responsible for architectural drawings, approvals, foundations and site readiness. The offer sets out the exact division of work.

ZTC uses mineral wool, cellulose insulation and wood fibre insulation. The company has an industrial Isofloc system for blowing cellulose and wood fibre insulation.

ZTC uses mineral wool, cellulose insulation and wood fibre insulation. The company operates an industrial Isofloc system for blowing cellulose and wood fibre insulation.

Panels are connected with long screws or special timber connectors. A wind barrier is used externally, a vapour control layer internally, and membranes are carefully taped across the building.

Panels are connected with long screws or special timber connectors. A wind barrier is used externally and a vapour control layer internally, with membranes carefully taped across the building.

Airborne sound insulation in timber houses can be very good, especially with cellulose or wood fibre. Impact sound in intermediate floors should be addressed with appropriate floor and ceiling solutions.

Airborne sound performance in timber houses can be very good. Impact sound in intermediate floors is addressed with appropriate floor and ceiling solutions.

For houses up to around 3 storeys, timber frame is often more economical. CLT may suit load-bearing structures, hybrid solutions or where exposed solid timber walls are desired.

For houses up to around 3 storeys, timber frame is often more economical. CLT may suit load-bearing structures, hybrid solutions or exposed solid timber walls.

A closed panel shell starts from €500/m² + VAT at 150 m² or more. For 100 m² to less than 150 m², the base shell rate is €575/m² + VAT. These rates assume Comfort panels and a simple rectangular house.

Rates use the gross external floor area across all storeys. The shell includes insulated external wall and roof panels, internal walls, transport and assembly by our crew. The externally finished package adds facade cladding, windows, external doors and roof covering. Foundations, interior finishes, building services and site costs are excluded. Quotes are in EUR; GBP equivalents are indicative. The final price and scope depend on your drawings, specification and site conditions.

Beyond the house price, you should plan for architectural design, approvals, topography, geology, energy certificate, foundations, external utilities, heating, ventilation, interior works and commissioning.

Beyond the house price, you should plan for architectural design, approvals, topographic survey, geology, energy certificate, foundations, external utilities, heating, ventilation, interior works and commissioning.

Planning an energy-efficient timber house?

Send project information so ZTC can review the structure and scope against your target.