What are the Passive House Standards?

To be certified as a passive house a building must meet certain standards as set by the Passive House Institute:

• Space heating demand must be ≤ 15 kWh/(m²a) per annum, or 10 W/m² for heating load
• Total cooling demand ≤ 15 kWh/(m²a) + 0.3 W(m²aK) – DDH
• Total primary energy consumption for hot water, heating and electricity ≤ 120 kWh/m²
• Air leakage ≤ 0.6 x house volume per hour

While these standards aren’t legal requirements when building a home, they are required should you wish to receive Passive House Certification from the Passive House Institute. If passive house standards are met conventional heating methods are not required such as boilers, radiators and open fireplaces.

Passive House Insulation Requirements

Insulation plays a key role in the design and build of passive houses. Typically, additional insulation is required than what would be found in a house built to typical building regulations. Insulation is used to reduce the transfer of heat through the building’s walls, roof and floors. U-Values must be low and are typically within the range of 0.10 to 0.15 W/m²/K). A variety of insulation materials may be used, including expanded polystyrene (EPS). Thicker walls and insulation are usually required to achieve these lower U-Values.

Energy Efficiency

On average, Irish houses require 9,722 kWh of energy for space heating purposes per year, resulting in 2,855kg of CO² emitted into the atmosphere. A house meeting Passive house standard typically requires as little as 1,500 kWh of energy per year to meet space heating requirements. The reduction in energy demand results in a drastic cut to the carbon dioxide released into the environment to 176kg per year and a significant savings on energy bills. The heating cost for a 150m² house would be in the range of €100 per year should it meet passive house standards.

WHAT IS nZEB – Near Zero Energy Building?

Meet & Exceed Ireland’s New Building Regulations

U-values measure the effectiveness of insulating materials. The lower the U-value, the less heat will be lost through a building element, like an external wall or the foundation of a house. Ireland’s Building Regulations Part L (Conservation of Fuel and Energy) have changed as of the 1st of November 2019.

These changes will lower the U-value requirements for many building elements. The new regulations and changes to (Part L 2019) are displayed below.

New Buildings – Part L 2019

Existing Buildings Part L 2019

Major Renovation and nZEB

The updated TGD Part L 2019 sets out requirements for dwellings that undergo major renovation. Major renovations are considered when more than 25% of the building’s surface area (the building envelope) undergoes refurbishment or renovation. The TGD states that the performance of entire building should be improved to a cost-optimal level where technically, functionally and economically feasible. The cost optimal performance level is considered 125 kWh/m²/yr when calculated in DEAP.

To calculate the surface area, the entire external envelope needs to be considered. This includes the external walls, floors, roof, windows, doors etc. TGD Part L 2019 defines the envelope as the surface area of the building “through which it can lose heat to the external environment or the ground, including all heat loss areas of walls, windows, floors and roof”.

To calculate the percentage that would trigger a major renovation, take the building element and divide by the total surface area (of the building fabric). For external walls, we would divide 150m2/386m², giving us a percentage of 39% of the surface area. This means external insulation or internal wall dry lining upgrades would be considered a major renovation as more than 25% of the surface area will undergo refurbishment. The cost optimal level of 125 kWh/m²/yr requirement means that this dwelling would need to achieve an equivalent BER rating of B3 where it is technically, functionally and economically feasible to meet the updated requirements of Part L 2019 – Existing Buildings.

What works are considered major renovations?

Major renovations include cladding the external surface of the wall or dry lining the internal surface of a wall. Painting, re-plastering, re-slating or re-tiling are not considered to be major renovations. In addition, attic insulation installed at ceiling level between the joists and installation of cavity wall insulation are not considered to be a “major renovation to the surface area”.

Part L does not consider it to be technically, functionally or economically feasible to bring the entire building to cost optimal level when replacing the surface area of roofs, floors or windows. In addition, historic buildings (of architectural or historical interest) should aim for improvements to the building that are “reasonably practical”, i.e. the works should not harm the character or increase risk of long-term deterioration of the building fabric or fittings.

Dwellings that are damaged due to natural disasters (floor, fire, etc.) or a material defect are also exempt as it is not considered economically feasible to bring these renovations to a cost optimal level.

Meeting Part L 2019 – New Build

For both new build and retrofit, Part L defines the requirements as buildings being designed and constructed to limit the amount of energy required for operation (energy performance) and its associated carbon emissions (CO2) as is reasonably practicable.

For new build this includes:

• Limiting the calculated primary energy consumption and related CO2 emissions as reasonably practicable using DEAP (Dwelling Energy Assessment Procedure). This tool is offered by the Sustainable Energy Authority of Ireland (SEAI).
• A significant percentage of the energy required comes from renewable energy sources, generated either on or off-site.
• Heat loss is limited, and heat gain is optimised through the building’s fabric.
• The use of highly efficient space and water heating systems, including the system’s controls and source. The use of oil or gas-fired boilers requires systems with at least 90% efficiency (seasonal).
• That all buildings are designed to avoid the need for cooling systems.
• Ensuring the owner/operator of the building understands all systems, maintenance requirements and is operated to use as little fuel as possible.

Meeting Part L 2019 – Existing Buildings

Meeting Part L 2019 for existing builds is much the same as new builds, however, includes the following additions:

• Controlling the output of space heating and hot water systems.
• Limiting heat loss from a variety of components including pipes, ducts and vessels used for storage or transport of hot water and air.
• Meeting the cost optimal level of energy performance when existing buildings undergo major renovation, as explained in further detail above.

Thermal Bridging

Care should be taken to avoid thermal bridging around common junctions, including windows, doors, wall openings, at junctions between elements to name a few. The DEAP methodology considers heat loss from thermal bridges when calculating energy use and CO2 emissions. In any case, thermal bridging should not pose a risk of either surface or interstitial condensation.

Insulated Concrete Formwork (ICF)

Why Choose ICF?

ICFs consist of high-density polystyrene panels 1200mm long, 400mm high, and 65mm wide, spaced apart by high strength polypropylene webs. The forms provide a fully insulating, permanent shuttering system into which concrete is poured.

Once cast, the solid concrete core not only provides the necessary structural integrity for the building, but also excellent sound insulation, fire safety, thermal mass and durability for the structure’s lifetime.

The polystyrene panels of each block provide the thermal insulation to the structure, with U-values between 0.24 W/m2K and 0.13 W/m2K being easily achievable.

The forms, being extremely light (only 3.5 kg each), are simple and easy to build, with all of the attendant handling and safety benefits. So, if you’re looking to construct bespoke new builds, then let ICF be the solution for your construction needs.

ICF for Architectural New Homes

Amvic ICF is the strongest insulating concrete formwork system on the market.
There are many benefits that ICF can bring to your architectural new homes project. Simplicity & convenience is just a few to mention.
The powerful combination of the patented, reversible FormLockT interlock, EPS composition, innovative web design and web spacing result in:

• A simple, strong formwork system that requires less support during installation giving straight, flat and plumb walls.
• Less wastage when compared against other ICF or building systems.
• The ability to withstand internal concrete vibration, ensuring a structurally superior wall.
• Increases speed of construction.
• Reduces labour costs.
• Provides the highest level of performance during and after construction.

Therefore, ICF is a must when it comes to any new project that relates to architectural new homes.
ICF walls can be finished internally by gypsum board screwed directly to the integral webs.
A wide range of external finishes may be used including brick, stone, timber cladding, and renders. ‘Through-coloured’ polymer renders are the most popular form of render finish, a wide variety of colours and textures being available.
As can be seen, ICF is indeed a very cost-efficient solution for bespoke new builds and architectural new homes. Contact us today to find out more information.