How to Design a Passive House for Dummies

December 26, 2021 Post a Comment

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'. However, MosArt 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.

KEY COMPONENTS

Passive House Component	Typical Passivhaus Standard Required for Irish Climate
Super Insulation (walls, floor, roof)	U < 0.15 W(m2K)
Triple Glazing	U < 0.8 W(m2K)
Mechanical Heat Recovery Ventilation	Heat recovery efficiency > 75%
Small capacity back-up heating system	Pellet boiler, compact unit, gas, etc.
Heat delivery	Normally through air ducting, but could be underfloor heating or radiators
Solar shading	Often required over south facing windows to prevent overheating in summer
Household appliances	A-rated recommended
Lighting	CFL or LED recommended
On-site renewables	Thermal solar collectors for domestic hot water recommended

Precise detailing of your project will ultimately require testing and verification in the PHPP software.

CHALLENGES

As you might imagine, achieving a Passive House is no mean feat. Fret not, however, as MosArt has considerable experience in all aspects of design and construction and can help you from first sketch designs right through to project completion.

Key challenges

PHPP – all Passive House designs must be verified using the specialist Passive House Planning Package
Construction detailing – achieving the required level of airtightness and thermal bridging greatly depends on appropriate details
Right on-site - close inspection of details during the build is very important, especially regarding airtightness
Passive House Certification – if you would like to have your building certified as a Passive House, certification documentation must be completed and submitted to an approved Authority

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
MosArt have the project experience to keep your build cost as low as possible
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'

BEYOND PASSIVE HOUSE

A Passive House construction type offers the highest level of thermal comfort possible. However you may wish to go above and beyond passive house standards by incorporating your own off-grid power supply onto your passive house.

Additional features such as photovoltaic panels and wind turbines can help you achieve this by feeding as much energy into the grid as you take out. A construction that meets this criteria is knows as net carbon-neutral.

Some buildings actually generate an excess of power, on average feeding more electricity into the grid than they take from it. We call this an Energy Plus House.

This excess energy can be sold to the grid, or can be used to power other needs, such an electric car. Just imagine, no more utility bills or car fuel expenses!

This is not the future. It's the present! MosArt can make this your reality. Call us today on 0404 25777