What is a Passive Home?
A passive house is a building in which a comfortable interior climate can be maintained without active heating and cooling systems. Essentially, the house heats and cools itself, hence "passive".
The combined energy consumption of a passive house is less than the average new European home requires for household electricity and hot water alone.
The combined end energy consumed by a passive house is therefore less than a quarter of the energy consumed by the average new construction that complies with applicable national energy regulations.
How does it work?
There are four key areas that comprise the Passive Home system:
1. Very high levels of insulation with minimal thermal bridges
2. Intelligent use of solar and internal gains
3. Excellent level of airtightness
4. Good indoor air quality provided by a mechanical ventilation system
With these features in place, a Passive House does not need a traditional heating system or active cooling to be comfortable to live in - the small heating demand can be met using a small electric heater within the ventilation system (although there are a variety of alternative solutions).
ICFs – air tight, insulating and incredibly robust
Insulated Concrete Formwork is a series of interlocking lightweight modular blocks made of EPS (Expanded Polyurethane Sheeting).
When assembled and filled with concrete they create a reinforced concrete wall with exceptional thermal qualities, no thermal bridges and incredible durability, making them popular in areas prone to earthquakes, tornados and forest fire.
ICF walls have U-values as low as 0.11 w/m²k making them ideal for zero energy buildings – and because they are manufactured to fit your design the building process is quick, tidy and precise, with lower labour and equipment costs than alternative methods.
Because of the comprehensive range of components, ICFs offer unbelievable flexibility of design and allow you to choose internal and external cladding in a wide range of finishes, including plaster, masonry, curtain walling and renders.
How are air circulation and additional heating requirements catered for?
With ICFs supplying the necessary insulation and airtightness, you need a complimentary system to provide adequate ventilation and prevent the air getting stale, as well as make up for any shortfall in heating requirements.
This is achieved most efficiently by transferring heat from the stale to the fresh air during the ventilation process. Using our heat transfer system, heat passes from hot air to cold air – it’s a process that is so efficient that air entering the room will only be approximately one or two degrees colder than the room it enters.
Technical specifications for Passive Homes:
For Europe (40o - 60o Northern latitudes), a dwelling is deemed to satisfy the Passive House criteria if:
the total energy demand for space heating and cooling is less than 15 kWh/m2/yr treated floor area
the total primary energy use for all appliances, domestic hot water and space heating and cooling is less than 120 kWh/m2/yr
These figures are verified at the design stage using the Passive House Planning Package.
It is also essential to follow a quality control procedure to avoid onsite problems that may prevent excellent levels of airtightness and thermal insulation being achieved – NOXEL Passive Homes provide onsite management to ensure Passive Home specifications are met throughout the building process.
