1. Supervisor: Dušan Petráš PhD. EUR ING.,
Energy certification and indoor environmental quality of residential building
Sánka Imrich
Slovak University of Technology in Bratislava
Faculty of Civil Engineering
Department of Building Services
Supervisor: Dušan Petráš PhD. EUR ING.,
Veronika Földváry PhD.
REHVA student competition 2017 London

2. Content Introduction Building Description Energy Efficiency2
Content
Introduction
Building Description
Energy Efficiency
Methodology (IEQ), (IAQ)
Results (IEQ), (IAQ)
Discussion
Conclusion
Literature

3. 3
Introduction
Majority of the residential building in Central Europe was built between years 1948 and 1990, with the highest intensity of construction between years 1971 and 1980.
People are spending more then 80% of their times in indoor environment.
Therefore the building may complete as the energy efficiency requirements as the basics of a healthily environment.
Objectives
Evaluate the impact of the
energy saving measures on the
indoor environment before and
after complex refurbishment

4. Building description Location: Šamorín - 25 km SE from Bratislava4
Building description
Location: Šamorín - 25 km SE from Bratislava
Competed in: 1964
Heating system: central heating
Ventilation: natural
(air outlet is installed only to the bathroom and toilet)
The evaluated residential building before and after renovation
The rising pipes and bathroom ventilation of the chosen apartment.

5. Energy Efficiency Refurbishment → 2015 Energy saving measures
External thermal insulation of walls 80 mm polystyrene
Roofing thermal insulation - 120mm of mineral wool
Basement ceiling insulation – 80 mm polystyrene
Complete replacement of windows and doors
Complete replacement of heating and DHW systems
Installation of control valves
Hydraulic balancing of the heating system

6. Energy Efficiency Heat demand Heat loss Energy need for heating6
Energy Efficiency
Heat demand
Heat loss
Energy need for heating
Energy need for DHW
Significant difference: External walls
Roof
Basement ceiling
No changes in: Heat gains
Solar gains

7. Energy Efficiency E → B D → B 54 % 7 Savings
555/2005 No. law of energy performance of buildings (300/2012 Z.z.)
building energy label
total energy consumption
E → B
primary energy consumption
D → B
Savings
54 %

8. Methodology Methodology Objective measurements:8
Methodology
Objective measurements:
Quantities:
Indoor air temperature (T) [°C] (IEQ)
Relative humidity (RH) [%] (IEQ)
CO2 concentration (CO2) [ppm] (IAQ)
NO2 concentration (NO2) [mg/m3] (IAQ)
Formaldehyde conc (H2CO) [mg/m3] (IAQ)
TVOC concentration (TVOC) [mg/m3] (IAQ)
Measuring equipment:
T, RH - Hobo data logger
CO2- VAISALA CO2 data logger
NO2- IVL diffuse sampler
H2CO- DSD-DNPH UmeX-100 diffuse sampler
TVOC - Perkin-Elmer adsorption pipe
Time and place:
January 2015 – Before renovation, N=20
January 2016– After renovation, N=20
Subjective measurements
Questionnaire survey
2 types of questionnaires (non renovated/renovated)
Methodology

9. Results of objective measurements (IEQ)9
Results of objective measurements (IEQ)
1) Temperature and relative humidity
Day and night average temperature was higher in the renovated building than in the non renovated. STN EN requirements fulfilled! (T>20°C; T<24°C)
The relative humidity was very similar in both types of residential building. STN EN requirements fulfilled! (RH>30%; RH<60%)

10. Results of objective measurements (IAQ)10
Results of objective measurements (IAQ)
2) CO2 concentration [ppm]
Boxplot:
CO2 concentration – full time measurements
25 a75 %
Median
Average
Max., Min.
Before renovation
CO2 [ppm]
Average
Minimum
Maximum
Day
1039
595
1550
Night
1411
742
2665
All the time
1203
657
2049
CO2 concentration before renovation
After renovation
CO2 [ppm]
Average
Minimum
Maximum
Day
1319
789
2209
Night
1925
865
3573
All the time
1570
869
2769
CO2 concentration after renovation
3) Air exchange rate (AER) [1/h]
Before renovation
Limit values CO2 (%)
CO2>1000 ppm [%]
CO2>1500 ppm [%]
CO2>2000 ppm [%]
CO2>2500 ppm [%]
Day 60 10
Night 75 40 5
Limit values of CO2 concentration before renovation
Air exchange rate [h-1]
Average
Minimum
Maximum
Before renovation (N=20)
0,61
0,32
1,15
After renovation(N=20)
0,44
0,21
0,76
CO2 concentration before and after refunrishment [ppm] (2 day interval)
After renovation
Limit values CO2 (%)
CO2>1000 ppm [%]
CO2>1500 ppm [%]
CO2>2000 ppm [%]
CO2>2500 ppm [%]
Day 75 30 10
Night 95 70 40 15
Limit values of CO2 concentration after renovation
The Slovak technical standard STN EN 15 251 defines the minimal AER intensity in the residential buildings must higher than n = 0.5  1 /h.

11. Results of objective measurements (IAQ)11
Results of objective measurements (IAQ)
4) Nitrogen dioxide (NO2) [mg/m3]
Limit value NO2 : 40 mg/m3 (WHO)
The average values did not exceed the limit before and after renovation.
NO2 concentration [mg /m3]
Average
Minimum
Maximum
Before renovation (N=20) 16 6 42
After renovation (N=20) 17 5 36
Nitrogen dioxide concentration before and after refurbishment.

12. Results of objective measurements (IAQ)12
Results of objective measurements (IAQ)
5) Formaldehyde (H2CO) [mg/m3]
The limit value for formaldehyde concentration is 100 mg/m3 (WHO).
The results did not exceed the limit value.
The data showed higher concentration after the building was renovated.
Formaldehyde concentration [mg /m3]
Average
Minimum
Maximum
Before renovation (N=20) 32 15 54
After renovation (N=20) 43 23 67
Formaldehyde concentration before and after refurbishment.

13. Results of objective measurements (IAQ)13
Results of objective measurements (IAQ)
6) Volatile organic compounds(TVOC) [mg/m3]
Limit value - TVOC: 300 mg/m3
TVOC concentration before and after renovation
TVOC concentration [mg/m3]
Average
Minimum
Maximum
Before renovation (N=20)
569
179
1805
After renovation (N=20)
773
185
2362
TVOC concentration limit values:
Limit values of TVOC concentration
Before renovation
(N=20)
After renovation
TVOC > 300 µg/m³ (%) 80 85
TVOC > 500 µg/m³ (%) 50 60
TVOC > 1000 µg/m³ (%) 5 25
TVOC > 2000 µg/m³ (%)
TVOC concetration before and after renovation

14. The results of the subjective assessment (IAQ)14
The results of the subjective assessment (IAQ)
7) Ventilation habits of the occupants
Changes in the ventilation habits of the occupants:
The first part of the table expresses ventilation habits of the inhabitants. (Several times a day, every day)
Second part of the table takes into account the duration of the ventilation.
The relation between the ventilation and the air exchange rate (left)
The relation between the ventilation and the perceived air quality (right)
Increasing the duration of ventilation is directly proportional to the intensity of air exchange rate, which clearly effects better air quality in the evaluated apartments.
Ventilation
Before renovation
(N=20)
After renovation
Whole apartment
Bedroom
Living room
Frequency of ventilation [%]
More than once a day 70 40 60 30
Daily or almost daily
The average duration of ventilation [%]
3.5 min 25 15
7.5 min 35 20
20 min
30 min
Majority of the inhabitants did not change the habits of ventilation after renovation.
Most of them are ventilating in the living room for 7,5 min.
In the bedroom the occupants are ventilating almost every day.
Before renovation the occupants ventilated in average 7,5 min. After the renovation in average 20 min.

15. Discussion 1 Objective measurements15
Discussion 1 Objective measurements
Based on the results mentioned above, the renovation of the buildings contributes greatly the quality of the indoor environment and may cause its degradation.
Higher indoor temperature (20,9 → 22,2 °C)
Decreased AER (0,61 → 0,44 1/h)
Increased concentrations of harmful substances :
TVOC (569 → 773 mg/m3) !!!
Formaldehyd (H2CO) (32 → 43 mg/m3)
Carbon dioxide (CO2) (1203 → ppm) !!!
The concentration of these toxic substances is greatly impacted by the used thermal insulation system and the quality of the installed windows.

16. Discussion 2 Subjective measurements16
Discussion 2 Subjective measurements
The majority of the occupants has not changed their ventilation habits after renovation
The average ventilation time is 7,5 min ( living room)
In the bedroom occupants are not ventilating every day.
With 20 min. ventilation the AER rises to 0,6 1/h
With 30 min. ventilation the AER rises to 0,8 1/h

17. Conclusion P A R A D I G M AER 0,6 1/h AER 0,4 1/h Energy class „E“17
Conclusion
Complex refurbishment of dwellings in Slovakia could cause reduced indoor air quality. In the case the CO2 concentration would not be reduced, the ventilation intensity should be increased (for instance via application of intelligent or mechanical ventilation systems) to reach the quality of indoor environment, at least, to the level of former state, before refurbishment.
P A R A D I G M
AER 0,6 1/h
AER 0,4 1/h
Energy class
„E“
Energy class
„B“
54% energy saving

18. 18
References
Jurelionis A., Seduikyte L. (2010) Assessment of indoor climate conditions in multifamily buildings in Lithuania before and after renovation. 2nd International conference advanced construction. Kaunas, Lithuania.
Földváry V., Bekö G., Petráš D. (2014) Impact of energy renovation on indoor air quality in multifamily dwellings in Slovakia. Proceedings of Indoor Air 2014, Hong Kong, Paper No. HP0143. Arash Rasooli, Laure Itard, Carlos Infante Ferreira, “Rapid, transient, in-situ determination of wall’s thermal transmittance,” in Rehva Journal, vol. 5, 2016, pp16-20.
Földváry V., Bekö G., Petráš D. (2015) Seasonal variation in indoor environmental quality in non-renovated and renovated multifamily dwellings in Slovakia. Proceedings of Healthy Buildings Europe 2015, Eindhoven, Paper ID 242.
Földváry V. (2016) Assessment of indoor environmental quality in residential buildings before and after renovation. Doctoral thesis. Bratislava, Slovakia.
Bekö G., Földváry V., Langer S., Arrhenius K. (2016) Indoor air quality in a multifamily apartment building before and after energy renovation. Proceedings of the 5th International Conference on Human-Environment System, ICHES 2016 Nagoya, Japan.
Persily A. K. (1997) Evaluating Building IAQ and Ventilation with Indoor Carbon Dioxide. ASHRAE Transactions. 103, Vol. 2.
N. Klepeis, W. C. Nelson, W. R. Ott el al. The National Human Activity Pattern Survey (NHAPS): a resource for assessing exposure to environmental pollutants. Journal of Exposure Analysis and Environmental Epidemiology. 11, 2001, pp. 231–252.
Kotol M., Rode C., Clausen G., Nielsen T. R. (2014) Indoor environment in bedrooms in 79 Greenlandic households, Building and Environment, Vol. 81, pp
Bekö G., Toftum J., Clausen G. (2011) Modelling ventilation rates in bedrooms based on building characteristics and occupant behaviour. Building and Environment, Vol 46, pp
Sánka I., Földváry V., Petráš D. (2016) Experimentálne meranie CO2 a intenzity výmeny vzduchu v bytovom dome. TZB-Haustechnik, Vol 25, pp
Sánka I., Földváry V., Petráš D. (2017) Evaluation of Indoor Environment Parameters in a Dwelling before and after renovation. Magyar épűletgépészet Vol, 65, pp
Sánka I., Földváry V., Petráš D. (2017) Experimentálne meranie toxických látok vo vnútornom vzduchu pred a po obnove bytového domu. TZB-Haustechnik, Vol 26. 2/2017, 6p (in print)

19. Slovak University of Technology in Bratislava
Federation of European Heating, Ventilation and Air Conditioning Associations
REHVA Student Competition
LONDON 2017
Imrich Sánka
Slovak University of Technology in Bratislava
Fculty of Civil Engineering
Department of Building Services
Thank you for your attention!

20. Questions?