What's Passive Design
Updated: Jan 3, 2022
BENEFITS OF A PASSIVE HOUSE
There are many reasons to build a Passive House, as outlined below:
Whole house comfort all year round
High quality indoor fresh air providing health benefits
Open plan and bright living spaces with strong connection to your garden
Very low heating bills, especially important with rising energy prices
Superior construction detailing, built to last
Low carbon emissions – doing your bit for the environment
Future proof your home, keeping ahead of current energy regulations
Join the 17,000 or so other Passive House home owners across Europe
WHAT IS A PASSIVE HOUSE?
There are different interpretations on what constitutes a ‘Passive House’. O' Dea Architects uses only the definition provided by the Passivhaus Institut in Darmstadt, Germany, as follows:
Maximum annual space heating requirement of 15kWh per square metre: 15kWh/(m2a)
Minimum airtightness of 0.6 air changes per hour measured at a pressure of 50 Pascal: n50 0.6 1/h
Maximum annual primary energy requirement of 120kWh per square metre (domestic hot water, heating and auxiliary electricity): 120kWh/(m2a)
Optimal heat load of 10 W per square metre: 10W/m2
Achieving the first three of the above is required for official Passive House Certification. The optimal heat load above should be achieved if you wish to heat your home via the mechanical ventilation system.
PASSIVE HOUSE COMPONENTTYPICAL PASSIVHAUS STANDARD REQUIRED FOR IRISH CLIMATE
Super Insulation (walls, floor, roof)U < 0.15 W(m2K)Triple GlazingU < 0.8 W(m2K)Mechanical Heat Recovery VentilationHeat recovery efficiency > 75%Small capacity back-up heating systemPellet boiler, compact unit, gas, etc.Heat deliveryNormally through air ducting, but could be underfloor heating or radiatorsSolar shadingOften required over south facing windows to prevent overheating in summerHousehold appliancesA-rated recommendedLightingCFL or LED recommendedOn-site renewablesThermal solar collectors for domestic hot water recommended
Precise detailing of your project will ultimately require testing and verification in the PHPP software.
HOW MUCH DOES A PASSIVE HOUSE COST?
As expected, it is more expensive to build a passive house than a conventional house.
Extra construction cost is likely to be 10% to 15% more, but savings on utility bills completely offset this after just few years.
Heating and hot-water costs for a Passive House should be in the region of just €0.15 per square metre, per year
Energy efficiency increases the resale value of your property
It might be possible to get grant-aid towards your project – we can advise
Carbon neutral housing is here now – make sure you don’t build a ‘dinosaur’