St Ive Rural Passivhaus...St Ive Rural Passivhaus WARM: Low Energy Building Practice Step 1: Reduced...
Transcript of St Ive Rural Passivhaus...St Ive Rural Passivhaus WARM: Low Energy Building Practice Step 1: Reduced...
St Ive Rural Passivhaus
�WARM: Low Energy Building Practice
Step 1: Reduced area
By terracing the houses the number of
external walls is reduced. This more
compact shape means that the heat
loss is smaller without increasing the
performance of the building fabric.
Result: Cost effective & low energy
By making sure the building form works for us the
additional cost of achieving this stringent target should
not be excessive.
The additional cost is split between extra design time,
extra build time and the increased cost of the glazing
and the ventilation unit.
On the continent this cost is approximately 5-10% of the
build cost and is expected to drop as designers and
builders become more experienced
Step 3: Glazing & shading
Passivhaus windows add signifi-
cantly to the additional cost.
Because of this we spent a long
time with the architects fine
tuning the window location, size
and orientation.
This resulted in large windows to
the South (shown in the diagram)
and smaller windows to the North.
There is no glazing to the East or
West facades as this would be
difficult to protect from
overheating during the summer.
Step 2: Simplicity rules
The basic building shape for all the houses is very
simple. This means the form will be easier to design
and build so there is a better chance of achieving
the stringent targets for airtightness and thermal
performance that Passivhaus requires.
The external form is then made more aesthetically
interesting through the addition of gables,
balconies and external storage which does not
penetrate the thermal envelope.
7 The Crescent, Plymouth PL1 3AB 01752 542 546 [email protected]
Step 4: Think thick
The foundation of the design is high levels of
insulation. This means the walls, floor and roof
in the St Ives house will be approximately
500mm thick
Step 5: Details details details...
A much more robust approach to heat loss is
taken. Every joint is assessed to ensure heat
is not escaping. This requires every wall-floor,
wall-wall, wall-roof, wall-window joint to be
investigated, and where excessive loss found
the design is modified.
Step 8: Heat recovery
A mechanical ventilation system allows the
heat from the stale air extracted from kitchens
& bathrooms to be recovered and transferred
to the fresh air supplied to other rooms. This
means that excellent air quality is achieved
with minimal heating requirement.
This ventilation system is simple and requires
little maintenance
The Result
Because of the measures detailed the building
needs very little heat input to keep comfort-
able and warm. For the St Ives project we will
only need a small electric heater in the living
room instead of traditional central heating.
Once completed, we will hopefully achieve
certification from the Passivhaus Institute in
Germany
Step 6: Airtightness
Once insulated to a high level the majority
of heat escapes through draughts. By
careful design and construction these
draughts can be eliminated which greatly
improve the comfort of the building
Step 7: Free heating
The triple-glazed windows are specially
designed to allow heat from the sun in
whilst stopping heat from the room out.
South-facing glazing is sized to get as
much free heat from the sun during the
winter whilst shading (in the form of
overhangs) stops sunlight during the
summer so the building doesn’t get too
hot.
St Ive Rural Passivhaus
�WARM: Low Energy Building Practice 7 The Crescent, Plymouth PL1 3AB 01752 542 546 [email protected]