Insulation Airtightness Design for Health and Comfort
Building Energy Ratings

Architecture

The best time to include energy efficiency measures is when a building is being designed and built. Maximum benefit for the least cost will be gained when energy efficiency measures are incorporated from the beginning of design process. Energy efficient design will provide increased comfort levels, reduced damage to the environment and can yield considerable savings in financial terms.

A high Building Energy Rating (BER) is achievable but it must be understood that to go from a B3 to an A3 requires substantial consideration and detailing of new construction methods and to go from an A3 to an A1 requires a huge shift and sea change in construction methodology, standards and design.

The current Department of the Environment (DoE) Part L Building Regulations are being continually upgraded in order to catch up with higher building standards throughout Europe. As such the DoE website should be regularly checked for these updates and new standards.

While our current and proposed upgrades of standards and requirements of Building Regulations Part L over next years should lead to higher ratings we should nonetheless be striving to better these standards at all times. Throughout Europe higher standards are the norm with thousands of “Passive Homes” being constructed and many “Carbon Neutral Homes “ planned.

Building sustainable homes is about more than just minimising carbon dioxide emissions. We also need to build and use our homes in a way that minimises their other environmental impacts, such as the water they use, the waste they generate, and the materials they are built from.

Passive House (PassivHaus)

A “Passive House” is properly a building in which a comfortable interior climate can be maintained without active heating and cooling systems (Adamson 1987 and Feist 1988). The house heats and cools itself, hence "passive".

Dr. Wolfgang Feist founded the “Passivhaus Institute” in 1996 which acts as the Certification Institute testing the various required technologies inherent in Passive Houses and to be a true “Passive House” a house should be certified by this Institute. There are now thousands of these homes throughout Europe but only a few here in Ireland.

The term “Passive House” refers to a specific design and construction for residential buildings with good comfort conditions during winter and summer, without traditional heating systems and without active cooling.


Typically this includes:
  • excellent insulation levels with minimal thermal bridges,
  • carefully planned utilization of solar and internal heat source gains.
  • high levels of airtightness of the building,
  • good indoor air quality guaranteed by a mechanical ventilation system with highly efficient heat recovery,
and most importantly as specified in “The Passive House Planning Package” (PHPP) calculation modeled by the Institute for Irish latitudes:
  • the total energy demand for space heating and cooling is limited to 15 kWh/m²/y (4755 Btu/ft²/yr) of floor area of building.
  • the total primary energy use for all appliances, domestic hot water and space heating and cooling is limited to 120 kWh/m²/y (38039 Btu/ft²/yr)
Important points or features about the “Passive House” standard in relation to quality are that:
  • The actual quality of the building is probably related more to what cannot be seen than by what can been seen.
  • The high quality of design and build are not just ‘nice to have' but fundamentally necessary to achieving the low energy usage.
  • The acid test for the homeowner will not be whether it looks high quality but whether the quarterly energy bill is near to zero. This test is entirely objective and indisputable. (An annual heating bill of around €150 based on gas prices for a 100m2 home is expected.)

In short, a very long awaited cultural revolution in design and site practice is needed if we are to adopt the “Passive House” approach. This would mean embracing the essential methodical and on-going training, auditing and testing procedures on site which are necessary components of the “Passive House” process.

The combined accepted energy consumption of a “Passive House” is less than the present average new Irish home requires for household electricity and hot water alone. With this only as a starting point, any additional energy requirements should be completely covered using renewable energy sources.

The following are the basic features that distinguish passive house construction:

  • Compact form and good insulation:
  • Southern orientation and shading considerations:
  • Energy-efficient window glazing and frames:
  • Building envelope air-tightness:
  • Passive preheating of fresh air:
  • Highly efficient heat recovery from exhaust air using an air-to-air heat exchanger:
  • Hot water supply using regenerative energy sources
  • Energy-saving household appliances:

Carbon Neutral House/Zero Carbon Development.(ZED)

Dwellings constructed to these standards take the design and building process to another level that we should all aspire to.