Passivhaus and Ciren Coho

One of the most important requirements in our Client Brief is that our buildings – housing and common house – should be built to ‘passivhaus’ standard.

What is the passivhaus standard?

Passivhaus is a voluntary standard aimed at minimising energy use in buildings for space heating to greatly reduce their ecological footprint. To meet the Standard, a building must use less than 15 kWh/m2 of floor area per year for heating. This implies: a high level of insulation and air-tightness; the use of solar gain to provide heat; and minimal thermal bridging (gaps in the insulation).

Reaching the passivhaus standard requires very precise design by the architects, since they must be able to predict accurately the energy use of a building before it is built. The Passivhaus Trust, which maintains the Standard, provides a computer package (Passivhaus Planning Package or PHPP) which must be used in the design process, and this calculates estimates for energy use corresponding to the targets to be met. There are many computer packages and methods to estimate the energy use of buildings, but PHPP has been shown, across many projects, to provide very accurate estimates.


Why is it so important to our community?

It is important to us that our houses are very cheap to live in and have the same cost to heat in a year as a conventional house has in a month. We cannot assume that all our companions in the cohousing will be well-off and it would be immoral to build houses that swallow a high proportion of a limited income in energy costs.

It is important to us that our buildings use as little energy as possible so that we can generate a high proportion where we live using our own solar panels. This means that the energy use of our homes will be only a small demand on the National Grid to reduce our climate impact as far as possible.

It is important to us that our houses can be peaceful places – even if we choose to make some noise - and passivhauses are well-known for keeping out noise.