This document summarizes the key lessons learned from building three Passivhaus schools in Wolverhampton with no extra budget for the Passivhaus standard. It found that higher internal heat gains from students led to more comfortable classrooms despite less solar gain from smaller windows. Simpler designs for ventilation, kitchens, and heating systems performed well while costing less than more complex alternatives. Monitoring identified areas for improvement in summer ventilation strategies and building management systems. Overall, the schools demonstrated that the Passivhaus standard can be achieved affordably in schools through design optimizations and occupant feedback.

1. Building a Better Passivhaus School
19th
International Passivhaus Conference Leipzig 2015
Nick Grant
Alan Clarke
Elemental Solutions
@ecominimalnick
@AR_Clarke

2. Three Schools One Team
Oakmeadow Bushbury Hill Wilkinson
© Dennis Gilbert/VIEW
Team:
Architype, Thomas Vale, E3, Ion Acoustics, Price and Myers, Elemental Solutions
www.architype.co.uk
2012 RIBA West Midlands Winner2012 UK Passivhaus Trust Awards
2012 RIBA Special Award winner

3. Oakmeadow
(no extra budget for Passivhaus)
Image Courtesy Architype

4. Images Courtesy Architype

5. Bushbury Hill
(no extra budget for Passivhaus)
Image Nick Grant

6. Image Nick Grant

7. Image Nick Grant

8. Pending
Image Courtesy Architype. © Dennis Gilbert/VIEW
Wilkinson
(10% less budget than the others)

9. Structural slab
Air tight layer
Load
Image: Architype
Basic construction the same
Timber frame
Cellulose insulation
OSB air barrier
Level access
Floating slab on 250mm EPS

10. Image Courtesy Architype. © Dennis Gilbert/VIEW
On site: October 2012,
Complete: December 2013

11. Image Courtesy Architype. © Dennis Gilbert/VIEW
Client: Wolverhampton City Council
Value: £5,000,000 (€6,800,000)

12. Image Courtesy Architype. © Dennis Gilbert/VIEW
TFA: 2395m2
Kids: 420

13. Image Courtesy Architype. © Dennis Gilbert/VIEWImage Courtesy Architype. © Dennis Gilbert/VIEW

14. Images Courtesy Architype. © Dennis Gilbert/VIEW

15. Key Lessons
• IHGs – higher than in German schools
• Fenestration – less is more
• Ventilation – proof of original concept plus simplifications
• Kitchen – mature solutions refined
• Heating – one small boiler and radiators
• DHW – losses dominated so electric used
• BMS – still not resolved, do we need one?
• Occupant feedback crucial for learning

16. IHG due to KiddyWatts
Average for UK examples 5.7 m2
/child
Average for German examples 10.5 m2
/child
Difference in body heat = +1.32W/m2
+ 5-6 kWh/(m2
.a) of useful heating
(Against 15kWh/(m2
.a) target)
Image; Nick Grant

17. IHG

18. Meant Less South Glazing
Image Courtesy Architype. © Dennis Gilbert/VIEWImage Nick Grant

19. Can Afford More Shading
Image Courtesy Architype. © Dennis Gilbert/VIEW

20. Image Courtesy Architype. © Dennis Gilbert/VIEW

21. Minimised Glazing to Ground
Image Architype. Juraj MikucikImage Nick Grant
• Reduced cost
• Less winter heat loss and summer gain
• More useful space
• Better daylight

22. Higher IHG ‘cheat’;
So how much did heat demand increase
with less solar gain?

23. Wilkinson gas use 1 year
Special needs
school
Pre Passiv
BREEAM
Excellent
Oakm
eadow
(inc’ DHW
)
Bushbury
(inc DHW
)
W
ilkinson
(Electric DHW
)
ImageArchitype

24. Electricity
Image Architype
Wilkinson
(inc Electric DHW)
Oakmeadow
Bushbury
Lowest of group but still
higher than hoped.
Note St Luke’s has
window ventilation

25. Energy Use First Full Year
Gas for space heating 9.1 kWh/(m2
.a)
Gas for kitchen DHW 1.2 kWh/(m2
.a)
Electricity 51 kWh/(m2
.a)
PE 144 kWh/(m2
.a)
High electric use not yet diagnosed but prime suspect is accidentally
connected heater battery in kitchen vent and BMS control fault of
MVHR. Good summer comfort indicates internal gains are as
anticipated.

26. Summer Comfort Greatly
Improved
“The questionnaire survey of staff members in 3 passivhaus
schools found that Wilkinson classrooms were on average,
better rated in terms of thermal comfort and indoor air
quality.”
Chryssa Thoua, Architype. KEEN Project to be published 2015 with graphs & data.
KEEN
Post occupancy monitoring as part of Knowledge Exchange and Enterprise Network (KEEN) project
between Architype and Coventry University, led by the University of Wolverhampton and funded by
European Regional Development Fund (ERDF) and Architype.

27. Cascade vent used in all 3 schools
Works well, simple control, lower cost
MVHR
First floor ventilation schematic
Image Architype, Chryssa Thoua

28. Summer vent
Leave MVHR running in summer?
•Better air quality
•Easy to understand
•Simpler WC vent
Graph courtesy Architype, Chryssa Thoua
ppmCO2

29. German Primary School window

30. Not allowed in UK!
Alan Clarke Passivhaus Building Services design & occasional stuntman

32. Full commercial kitchens

33. Key points for kitchen vent
• All electric – no combustion products
• Variable speed air flow – comfort
• Robust 50% heat recovery delivers comfort. 12°C fresh
air is fine in kitchen, don’t need 17°C
Wilkinson improvements:
• Eliminated heating coil & so frost coils
• Electric heater fitted (against our advice) as fall back
measure but was to be isolated 

34. Kitchen Vent
Download the paper and presentation: www.elementalsolutions.co.uk

35. The Heating System
• One boiler for 2,400m2
building (84kW, <25kW demand)
• No weather compensation
• Radiators and TRVs You sure this is the
right boiler?
You sure this is the
right boiler?
Four times the size they
needed apparently
Four times the size they
needed apparently
Image Nick Grant

36. Hot Water
• With gas, circulation losses dominated, over 60%
• Local electric but only 7 units for whole school
• 8mm copper pipe for longer pipe runs so less heaters
• 2.7kWh/(m2
.a) PE standing loss
• Instantaneous gas in kitchen (c.a. 1.2kWh/(m2
.a)
1.7 litres/minute ‘sprays’Proof of concept test rig

37. BMS/BEMS
“Critics of BMS would do well to remember how building
services were controlled in the past. The simple controls that
used to be the norm – such as time clocks and thermostats –
were often either never adjusted or they were subject to
unauthorised tampering, resulting in huge amounts of energy
being wasted. What solved the problem was the introduction of
building management systems. This is one reason why such
systems are now the dominant form of HVAC control in non-
domestic buildings.”
Trend website

38. BEMS
• Claimed to save energy.
• Say £50k install, £5k/a tech support contract,
sensor & actuator testing etc
• Gas bill £1.5k/a so potential ROI=??
• See papers by Prof Axel Bretzke Frankfurt

39. One bit logic problem
BMS allows us to do clever things
e.g. WC vent in summer using MVHR
1 & 0 swapped in BMS logic – extract air
damper to hub space shut in winter mode.
•Spotted because of cool supply air (due to
vent imbalance)
•High fan power all winter (and noisy!)

40. BMS 2020?
“Critics of simple controls would do well to remember how
building services were controlled in the past. The complex BMS
controls that used to be the norm were often either never
adjusted or they were subject to unauthorised tampering,
resulting in huge amounts of energy being wasted. What solved
the problem was the introduction of simple thermostats and
timers. This is one reason why such systems are now the
dominant form of HVAC control in non-domestic buildings.”

41. A light switch, KISS
(Safety gear optional)
Image Nick Grant

42. Schools Conclusions
• Higher IHG assumption led to more comfortable
building & paradoxically lower heating demand
• Design simplification takes time and courage but
can save money and improve performance
• If something can go wrong it will but if it isn’t
installed it can’t go wrong.
• Thanks for listening!