Lauri Suu, Head of Housing Policy at Ministry of Economic Affairs and Communications for Estonia. This presentation was part of Indoor Environment Quality and Health - Evidence, best practices, and lessons learned from the Covid-19 crisis webinar that took place on 28th September during the 12th EUSBSR Annual Forum

1. Lauri Suu
Head of Housing Policy
Ministry of Economic Affairs and Communications
Estonia
Ventilation solutions in
apartment buildings

2. Why (Covid-19 context)?

3. Bad indoor climate is also expensive
– IAQ associated DALYs = 4900 DALY = 186 M€ cost for Estonian goverment in every year
Don’t save energy on the cost of indoor climate!
▪ DALY/year*million – Disability Adjusted Life Year. Blue: outdoor sources,
red: indoor sources. (IAIAQ, 2011)

4. 4
Recommendations for the existing buildings
1. Ventilation rates
2. Ventilation operation times
3. Overrule of demand control
settings
4. Window opening
5. Toilet ventilation
6. Windows in toilets
7. Flushing toilets
8. Recirculation
9. Heat recovery equipment
10. Fan coils and split units
11. Heating, cooling and
possible humidification
setpoints
12. Duct cleaning
13. Outdoor air and extract air
filters
14. Maintenance works
15. IAQ monitoring https://www.rehva.eu/activities/covid-19-guidance

5. 5
• Extend ventilation working periods (2 hours before and
after use)
• Reconfiguration of demand-side systems to maximum
designed productivity
• Avoid using exhaust air (recirculation)
• If exhaust air cannot be avoided, install ePM1 (F8) filters
(approx. 80% resolution, because the virus is not bare,
but inside the droplets)
• Technical inspection of rotary heat exchangers
• Install CO2 sensors in buildings (800 ppm yellow, 1000
ppm red)
Recommendations for the existing buildings

6. Ventilation systems in existing apartment buildings
• Apartment based Air Handling Unit (AHU) with Ventilation Heat
Recovery (VHR)
– Pro:
• High efficiency
• Guaranteed performance
• Occupant can adjust the speed
– Contra:
• Ductwork installation in apartments
• Expensive and requires space

7. • Centralized AHU with VHR
– Pro:
• High efficiency and guaranteed performance
• Minimal construction works in apartment
• Most common solution in Estonia now
– Contra:
• Difficult to use in buildings higher than
5 floors (too big ducts on the façade)
Ventilation systems in existing apartment buildings

9. • Exhaust AHU with heat pump HR
– Pro:
• Minimal construction works in
apartment
• Main solution in 9-storey buildings
– Contra:
• Electricity of heat pump
• Parallel heating for district heating
• Ventilation radiators to be used for intake air pre-
heating
(to domestic hot water and return of heating)
Ventilation systems in existing apartment buildings

11. • Room based AHU with VHR (not accepted when applying for reconstruction grant)
– Pro:
• Easy to install
– Contra:
• Wet rooms not solved
• Unbalanced, low heat recovery, too high noise, frosting issues
• too small pressure drop (wind and air due to stack effect blows though the system),
• too small airflow (many units are needed for the main bedroom),
Ventilation systems in existing apartment buildings

12. Evolution
– Since 2010
• Natural ventilation with
fresh air valves, exhaust
was not solved
• Room based AHUs
• First AHUs with heat
pump
– Since 2015
• No natural ventilation
• No room based AHUs
• Most common
centralized AHU
• Study 2015-2017
– Measurement protocols report required ventilation rates in all
apartments
– Measured in operation, average of all apartments 0,57 h-1
– Supply and extract air flows in the rooms are in adequate level
First time in the history renovated apartments have adequate
ventilation
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1,0
1,1
1,2
271
232
231
291
233
272
222
213
273
211
251
212
223
282
283
252
292
293
281
253
262
261
242
241
221
263
2103
2122
2102
2121
2123
2112
2111
2101
122
111
121
123
112
131
113
132
Õhuvahetuse
kordarv,
h
-1
Korteri kood Korteri õhuvahetuse kordarv
Soojustagastusega SP/VT
nSP/VT = 0,73 h-1
Soojustagastusega
VTSP
nSP/VT = 0,32 h-1
Soojustagastuseta
VT
nSP/VT = 0,32 h-1
Nõutud õhuvahetuse kordarv - 0,5 h-1
0
5
10
15
20
25
263-1
223-3
222-1
222-2
222-3
251-2
251-3
251-4
212-3
253-1
253-2
252-2
261-2
253-3
271-3
271-2
213-2
273-3
251-1
211-1
232-1
233-3
291-2
273-1
252-1
231-3
233-4
291-1
293-1
293-4
231-1
273-2
261-1
242-1
261-3
242-2
231-2
263-2
212-2
272-1
272-2
292-1
292-2
292-3
293-3
223-1
281-1
283-1
282-1
232-2
211-2
213-1
293-2
233-1
233-2
271-1
282-2
262-2
241-1
212-1
283-2
242-3
241-2
262-1
223-2
221-1
281-2
213-3
221-2
Sissepuhkeõhu
vooluhulk
toas,
l/s
Korteri kood
Elu- ja magamistoa nõutud õhuvooluhulk 10 l/s
Supply air flow rates in bedrooms
and living rooms, L/s