1. What kind of heat loss requirements nZEB and deep renovation sets for building envelope? Kalamees, T.; Lupišek, A.; Sojkova, K.; Mørck, O.C.; Borodinecs, A.; Almeida, M.; Rovers, R.; Kuusk, K.; Silva, S. Op t Veld, P
Central Europe towards Sustainable Building 2016
Prague.

2. Introduction Renovation process: History and today:
long-term process
problems with moisture safety
problems with thermal quality
problems with durability
no or very small potential for export
In future (and today):
quickly
high-quality
moisture-safe
integration of service systems
potential for export

3. Renovation in future
Advanced, prefabricated, innovative, multifunctional building envelope elements for MOdular REtrofitting and CONNECTions
Producers of modular renovation panels and construction companies want to know heat loss properties of building envelope:
thermal transmittance (U, W/(m2∙K)) of exterior wall, roof, floor, windows, doors, etc;
linear thermal transmittance (, W/(m∙K)) of connections, details, and thermal bridges;
air leakages (q50, m3/(h∙m2)) of building envelope.

4. Methods Energy performance leves: Before renovation
nZEB i.e. national Nearly Zero Energy Building definition;
DER i.e. deep energy renovation with 80% reduction of primary energy for:
space heating (+ pumps);
space cooling;
ventilation (heating, cooling, fans);
domestic hot water (DHW).
ZEB i.e. net Zero Energy Building = the primary energy use = 0 kWh/(m² a) (on annual basis) for:
space heating (+ pumps) and space cooling;
DHW.

5. Methods Energy performance leves
Five geo-clusters, six countries in Europe:
Denmark,
Estonia and Latvia;
Czech Republic;
Portugal;
Netherland.

6. Methods Energy performance leves Five geo-clusters in Europe
Country-specific typical buildings and energy performance regulations

7. Results: before deep energy renovation

8. Results: National nZEB requirements
In most of countries the nZEB of buildings is defined as (primary) energy use of whole buildings.
Average reduction of PE to nZEB was 70% (40…95%)
Minimizing heat loss of building envelope is not enough for nZEB in cold climate (Estonia and Latvia).

9. Results: National nZEB requirements
Differences in climate and nZEB regulations cause also different requirements for heat loss of modular prefabricated insulation panels in different countries:
The northernmost country, Estonia, the strictest requirements exists on heat loss of building envelope;
Denmark has stricter requirements than in Czech Republic
In warmest country, Portugal, requirements on heat loss of building envelope are the lowest for nZEB.

10. Results: 80% reduction of primary energy
May cause stricter or weaker requirements on energy performance than national nZEB requirement.
The production of heat and electricity on site is unavoidable in all countries except Denmark.
In Estonia almost the total area of the roof is covered with solar collectors and PV panels in Estonia

11. Results: ZEB (net Zero Energy Building)
To reach the goal:
minimizing the energy use
maximizing the energy production on site form renewable sources
In Central European milder climatic conditions the ZEB is possible in practice;
For multi-storey apartment buildings ZEB is extremely difficult if not impossible in cold climate (no physical place for PV panels).

12. Conclusions
For nZEB the strictest requirements on U-value are in Denmark and the lowest in Portugal;
For nZEB the thermal transmittance of the modular wall panels is:
5% from pre-renovation thermal transmittance in Latvia (Uw.nZEB0.19 W/(m2·K)),
10% in Estonia (Uw.nZEB0.11 W/(m2·K)),
up to 50% in Portugal (Uw.nZEB0.47 W/(m2·K)).
Results show the difficulties to reach ZEB in multistory apartment buildings in cold climate. There is not enough space to install renewables for energy production on site.

13. Future research
In H2020 MORE-CONNECT ( project results will be:
optimized (cost, used/embodied energy, technical)
other properties:
durability,
structural stability,
fire safety,
moisture safety,
acoustic,
price,
etc.