What Is A Passive House?

The following article aims to outline what a Passive House is and give information on what’s involved. Whilst The Greener Group does not build passive houses, we supply many of the renewable technologies required to enable a house to be classified as passive.

Introduction

You may or may not be familiar with the concept of “Minergie-P”.

This is a very popular standard used in Switzerland as a way of making the countries’ homes more energy efficient. “Minergie-P” has proven to be very successful as over 14,000 Minergie buildings have been voluntarily certified and widely backed by the Swiss Government, leading to the largest market of sustainable buildings, still unmatched by any other country across the globe.

“Minergie P” is a globally recognised success, leading to many other countries around the world trying to replicate, and change it for their own country.

Now we have our own response to this – Passive House.

A common misconception is that Passive House is a brand, but it is instead a construction concept, which has been given the name of Passive House. However, there is more to Passive Houses than just being energy efficient. Allow us to break them all down for you in this article.

What Is A Passive House?

Passive House buildings are often praised for a providing a high level of comfort. They rely on external energy sources such as body heat from its inhabitants and solar power to heat the home.

Appropriate windows with good insulation are essential to keeping in the heat, so you don’t have to use more energy to create more heat. It also requires a strong shell consisting of good insulated exterior walls, rood and floor slab to keep the heat during the winter months, and keep it out during the summer.

A ventilation system is also important to consistently supply fresh air, making for superior air quality without causing unpleasant draughts. This is similar to a generator, however you will not need to use up a lot of energy to keep it running and operating.

The average Passive House has got everything you need for a perfect home:

  • Comfort
  • Quality
  • Ecology/Sustainability
  • Affordability
  • Measurement Resulters
  • Versatility
  • Retrofits
  • Hands On Experience – See It To Believe It

How Does It Work?

So now you know what a Passive House is and what it entails, you may be wondering how it works exactly?

With the Passive House being a relatively new concept, many people are not aware of how it all works and how they can implement it into their own homes to make them more energy efficient.

Let’s take a look at how it works:

  • It requires less than 15 kWh for heating or cooling.
  • The heating/cooling load is limited to a maximum of 10 W/m2.
  • Conventional Primary Energy use may not exceed 120 kWh/(m2a) – but the future is renewable energy supply (PER) with no more than 60 kWh/(m2a). This is easy to accomplish with passive houses.
  • Passive Houses must be airtight with air change rates being limited to n50=0.6/h.
  • In warmer climates and/or during summer months, excessive temperature may not occur more than 10% of the time.
The Passive House is a sustainable construction concept that provides for affordable, high quality buildings as well as comfortable, healthy living conditions, and its principles are quite easy to understand:

As newer buildings are increasingly airtight, ventilation through joints and cracks alone is not sufficient to provide for fresh indoor air. Opening the windows as recommended won’t do the job either.

Fresh air is not merely a matter of comfort but a necessity for healthy living – Indoor Air Quality (IAQ) is the basic performance goal. Ventilation systems are therefore the key technology for all future residential buildings and retrofits.

Even though ventilation systems do require an extra investment to begin with, they will end up saving considerable amounts of energy costs, provided that they are highly efficient systems. Passive House quality ventilation systems will reduce the operating costs of any building.

This is where the Passive House concept comes in. As large amount of fresh outdoor air need to be supplied to the building anyway, why not use this air for heating? Without any extra amounts of air, without any recirculation of air, without any inconvenient noise or drafts? This way the ventilation system pays off twice.

This “supply air heating” concept only works in appropriately insulated buildings. In expert terms, the transmission and infiltration heating load must be less than 10 W/m2 to make sure that the required heat can be provided by the supply air.

The History Behind The Concept

Passive Houses were created back in 1990 as the first experimental homes including the Passive House concept in Darmstadt, South West Germany. These prototypes have now developed into the Passive Houses we know today.

However, one of the creators (Dr. Wolfgang Feist) decided that more research needed to be completed and more experiments needed to be carried out to develop this project more, so he set up Passivhaus Institute.

Dr. Wolfgang Feist set up the Passivhaus Institute in 1996. It was a research institute dedicated to developing the Passivhaus concept and it focused on encouraging countries around the world to adopt its standards to make the world a more eco friendly place to live.

This achieved moderate success as by 2001. we saw Passivhaus buildings showing up across Europe, but the majority of the Passivhaus establishments existed in mainland Germany and parts of Scandinavia. We then saw the very first Irish Passivhaus in 2005, followed by the very first United States Passivhaus being set up in 2006.

The very first Passivhaus set up in the UK was built in Machynlleth, Wales. They include a Stag Centre, an office and Y Foel, a private dwelling. There are other ones around the world, which includes schools, kindergartens, and for some even a supermarket. There is even one set up in the Netherlands.

It does not require any dock connectors for energy or water; it gets energy from solar hot water collectors and processes water through a built in water treatment system. It also has a heat recovery ventilation system, EPS insulation and IKEA furnishings.

What Are The Benefits?

So now you have all of the facts and information regarding Passive Houses, you are most likely thinking why they are beneficial to your homes and your lives? What are the positives of adopting the Passive House lifestyle?

  • Lower energy bills and protection from fuel price rises.
  • Warm, sung rooms without any draughts or cold spots in winter, and cooler rooms in summer.
  • Low maintenance costs.
  • Less technology to go wrong, so there are fewer heating emergencies and expensive repairs.
  • Peace and quiet when the windows are shut.
  • More wall space, as you don’t need any radiators – giving you more choice of where to place pictures, pianos or sofas.
There are even some advocates who also claim that you can gain some more floor space due to the fact that you do not have space taken up by radiators/heaters. However others argue, that it is not necessarily accurate as Passivhaus walls tend to be a lot thicker to provide more insulation to the house itself.

How Energy Efficient Are They?

So they are the benefits of having an energy efficient Passive House, but how energy efficient are they truly? Let’s break it down.

A Passivhaus requires 15 kWh of heating energy per square metre net floor surface per year (15 kWh/m2a). If you take that as being a typical, average UK home, that’s the equivalent of around £50 worth of gas per year.

A draughty gas heated Victorian Villa, would use 300 kWh/m2a and spend £1,000 a year.

Passivhaus states that a building does not exceed the 15 kWh/m2a standard, if it does then it cannot be classified as a Passivhaus.

What Is Superinsultation?

Hopefully you are now familiar with all of the main aspects and benefits of Passivhaus, but are you aware of the term superinsulation?

Superinsulation is simply a way of building that produce much greater levels of insulation than normal. So the costs of heating its internal spaces are lower than the cost of its hot water.

There are no set parameters that define Superinsulation, but a typical Superinsulated house would usually have these:

  • A U-Value is the rate at which heat passes through insulation, it should be more than 0.30 watts per square, if it is below that then that means that home has a low U-Value which means that they are a lot more energy efficient. The lower the U-Value, the better.
  • Built so that there is no place for the Insulation to escape where possible, such as when a wall meets the roof, foundations or any other walls.
  • If the house is as completely air tight as possible, especially when it comes to insulation around the windows and doors.
  • If the home is supplied with a heat recovery ventilation system to provide fresh air.
  • If the windows in the home are relatively small on all sides.
  • When a house is heated by a smaller system than your average, everyday home; such as a single backup heater system.
A Superinsulated house should have very low heating needs and therefore should mostly be heated by integral sources. This can be waste heat produced by lighting and electrical appliances, or could be the heat of the residents, pets and visitors.

The extra cost of building a home with Superinsulation can be balanced out by the fact that there is no need to install a central heating system.

Superinsulated homes actually are known to pre-date the Passivhaus movement, came. They came in standard shapes when they first came onto the scene, however these days they come in all shapes and materials.


Do Passive Houses Have Specialised Windows?

Well, in order to keep as much heat inside of the house as possible, the windows in the home are triple pane insulated glazing windows.

The space between the glass panes are sealed and filled with Argon or Krypton, the technology included a ‘low-emissivity’ coating, ‘warm edge’ glass spacers and specially developed thermally broken window frames.

Would You Require Any Special Furniture Or Fittings?

If you would like your home to comply with the Passivhaus specifications, you’ll need to choose your furniture and finishing’s carefully so that you are not polluting the air indoors.

his means that you need to check for volatile organic compounds (VOC’s), you’ll need to add a plant of some kind so that it can use the process of Photosynthesis to take in the carbon dioxide to turn it into oxygen.

It would also be helpful to open your windows on regular intervals.

Do All Passive Houses Look The Same?

Not remotely, they come in a wide variety of layouts and styles.

They can be built from dense materials or lightweight materials, but they always require a specific amount of internal mass to reduce the hot temperature in the summer and maintain stable temperatures in the winter months in order to prevent overheating.

You are able to choose the colour of the external walls. However they need to be specifically tailored to reflect or absorb heat, this can vary depending on the average temperature of where you live, this can alter the amount of colours that are available to you.

Some people believe that you cannot open the windows in a Passivhaus however this could not be further from the truth, quite the contrary in fact.

A Passivhaus is almost required to have windows as they need to be opened in order to release any heat that may have been building up throughout the day. During the winter months, it’s still possible to open the windows but the air inside may actually feel fresher than outside so most residents who inhabit in a Passivhaus usually prefer to keep them closed.

There is a little secret that some people like to discuss which is that when you leave your windows open all night, each night, it will reduce the internal temperature slightly and add a very slight increase to the overall amount of the Passive House’s energy use due to it having to accommodate to the change in temperature.

Summary

Hopefully you now have a good idea on what a Passive House is and what living in one entails.

They are the perfect situation for a person who is looking to take a more eco-friendly approach to life and do not want to live in a house that is becoming energy consuming.

A Passive House cannot only help save the environment but also save you money as you will not be using as much energy. Less energy equals less money, simple really.