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 info@peterwarm.co.uk

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 info@peterwarm.co.uk