How to Build a Carbon Neutral Home

Advice and Guidance About How to Build a Carbon Neutral Home

‘We all need to curb our carbon output – after all, households constitute 44% of the UK’s emissions’ – David Milliband

Introduction

First of all, what does it mean to be carbon neutral? You may have heard it referred to as having a carbon footprint. In other words, just as you may leave a footprint in the sand as you walk, the journey through your day will leave a trail of carbon dioxide, or CO2, that will be released into the atmosphere. So perhaps an important question to ask is, where does carbon dioxide come from? This could be from such things as diverse as volcanoes, car exhausts, factories, power and manufacturing plants and decaying plants and animals, to name just a few.

Many of these plants and animals became buried in swamps before they decayed, and over several million years they became the oil and gas that we burn to run our world today. And it’s at that point that their carbon is released as carbon dioxide. Scientists have come to realise that over-use of these is damaging our global home. It is no longer enough to simply use eco products; there is a need to balance the release of carbon dioxide into the atmosphere.

There are several ways that are currently being used to accomplish that. One way is to use renewable energy that creates a similar amount of useful energy, in other words compensating for the carbon emissions. Another way is to use renewable energies that produce no carbon dioxide. It is also possible to offset your carbon emissions by a payment added to your purchase of an item that uses carbon. This payment will then be used by companies that remove carbon from the atmosphere. This may be by planting trees or by using funding in several complicated ways known basically as carbon trading.

So there are many ways on a personal level that we can become involved in reducing our carbon emissions. What we are looking at are the specifics of building a carbon neutral home. This may be by building a new home or as is most likely the case for most of us, by making additions to our existing property.

What is a Carbon Neutral Home?

The general definition of a carbon neutral home is a zero energy building. When compared to traditional buildings which consumes 40% of the total fossil fuel energy of the US and European Union, it is easy to see why they are gaining popularity. The whole concept is becoming a more realistic option as research is growing and reduced costs in producing the technology are decreasing alongside the increasing costs of traditional fossil fuels.

There are very few areas within the home that are not affected by the carbon neutral potential. This may also include the manufacture of the products along with their use. One area that is showing a noticeable increase in the attempt to become carbon neutral is in the construction of affordable housing. This has been spurred on by the introduction of new building codes by the government, known as The Code for Sustainable Homes. Many of the codes used for building these homes are gradually being introduced into the building regulations for houses built for the private sector.

Is it Possible for me to build a Carbon Neutral Home?

The knock on effect of these changes has resulted in the formation of many new companies dedicated to providing information, services and products for the carbon neutral industry. Whether you require building advice, planning or building control advice, or are looking for carbon neutral products or services, a simple search for carbon neutral homes will provide a wealth of information. So it’s now possible to build a new home, or even extend your existing property using carbon neutral products, and alongside that, many companies will provide the calculations necessary to achieve your goal. But it’s also true that presently there are limitations to the concept as presently most calculations only include the energy required to operate the home and not other energies needed to manufacture and transport the goods.

This graph shows how you can reduce your home’s carbon output.

This graph shows how you can reduce your home’s carbon output.

Probably the most significant factor of energy consumption in the home is the heating, and possibly the cooling of your home, and it in this area that most of the ‘energy’ has been directed in finding ways to reduce our carbon footprint.

It would not be hard to drive along any road today and find a house with solar panels on the roof. It is considered one of the most effective ways of producing free energy and can even pay you back by selling the excess energy to the national grid. The problem for many can be the initial outlay required for the installation and should be a considered a long term investment. Once installed the energy is produced by sunlight and there are many companies offering installation of solar panels so it makes sense to use get the right electrical advice for your particular property, and a good place to start is the Energy Saving Trust. You may also need roofing advice as you are adding a considerable weight to your roof structure.

At the opposite end of the scale, a relatively inexpensive way of reducing your carbon footprint is by installing low energy light bulbs. A typical 100w low energy bulb will use 15% of the energy compared to a traditional light bulb. That means savings for you, and a vastly reduced carbon output. In fact, what may seem a relatively small change has been seen by the government as absolutely essential in the drive to lower our carbon footprint. It will soon be impossible to buy anything but a low energy light bulb for your home.

What Ideas are out there?

Low water use bathrooms

A toilet flushed in the 1970s would have used 26 litres of water. Installing a new toilet today would mean using 6.8 litres of water. For those wishing to have a completely carbon neutral toilet system, it is possible to install a compost toilet, where the smells are sucked away by a fan and the rest will be kept in a container where the waste eventually turns to dust, and installing taps that only work while your hands are placed underneath them means that no water is wasted.

This technician is in the process of installing some technology to reduce the house’s carbon output.

This technician is in the process of installing some technology to reduce the house’s carbon output.

Appliances

You can now choose to buy your appliances based on the energy they use. The EU has devised a rating system which must be shown on the appliance, enabling you to reduce your energy consumption through your choice of appliance.

Ground source heat pumps

Heat pumps installed at a depth of 1.5m to 2m below ground rely on the relatively even temperature of the earth below the surface. They extract that heat from the ground which can then be used in radiators, underfloor heating or warm air heating systems and hot water for your home. Once installed, they are an excellent source of passive energy in that they require no energy output to produce the heat.

Insulation

The most obvious way of reducing your carbon output is by not using the energy in the first place, and with that in mind the building regulations for insulating your home have changed drastically over the past 40 years. Our first home, purchased when new on a small estate of new homes in 1976, had absolutely no insulation whatsoever. You are now required to wrap your home up in a blanket in the endeavour to stop the slightest leak of warm energy. For existing homes it is possible to fill cavity walls retrospectively as well as upgrade the insulation in the roof area.

It is also possible to insulate your floor, walls and roof using recycled materials that further reduce the carbon output during manufacturing. Double glazing is also no longer just two panes of glass stuck together. There are several gases used between the panes in an attempt to slow the transfer of cold air from the outside glass to the inside, and also to keep the heat in.

Wind turbines

We have all seen the wind farms placed in groups towering above the countryside. But there are smaller versions available for the individual home. A wind turbine works by converting kinetic energy from the wind into electricity. Using the wind in this way to produce power is not new. For centuries man has used windmills in producing the energy needed to grind grains into flour or to pump water for land drainage and sometimes to extract groundwater.

A typical wind turbine system for your home could easily generate more power than your lights and electrical appliances use, but a lot of thought needs to go into where the turbine is positioned as they can also generate a certain amount of noise.

A house built with its carbon footprint in mind.

A house built with its carbon footprint in mind.

Rainwater harvesting

Rainwater harvesting is slightly more involved than sticking a water butt under the gutter of the house. Interestingly, not harvesting rainwater is a relatively modern phenomenon. For centuries the survival of communities has depended on the practice and it is only in recent times that the responsibility has been taken away from us by water companies. By taking back that responsibility we are accomplishing several things, not the least of them is being more conscious of the resources that we are using. The installation of a rainwater harvesting system requires minimal skills and can be sized to meet the water demand throughout the dry water season. The systems can be as basic as providing water for irrigation, through to cleaning and even drinking water. There are several companies that provide holistic harvesting systems to create a complete solution for domestic, garden or commercial systems.

Recycling and reuse

Recycling is defined as ‘processing used materials (waste) into new products to prevent waste of potentially useful materials.’ The process is also meant to reduce the consumption of fresh raw materials, thus reducing energy usage. So recycling is perhaps one of the most significant ways of reducing the carbon footprint.

So what are some of the recyclable materials that you might come across? The list is growing daily but includes glass, metal, paper, textiles and plastics as well as electronics. What is also happening is that many products are being made so that they can be recycled at end of their life. What is perhaps surprising is that materials are seldom recycled to produce the same material, as this is more expensive and often uses more energy than producing the same product from raw materials, so most recycled products are made from different materials. Some examples of this are bricks made from recycled plastics, glass or even landfill waste. It is also possible to get timber made from recycled wood fibre and insulation. We shall be looking at the viability of many of these products in future articles.

What Materials Are Available?

Environmentally friendly concrete?

One of the most unfriendly and environmentally damaging products used in building today is looking like it might be getting a facelift. Scientists at Novacem, at British concrete manufacturer have claimed that they have developed a new form of concrete which not only absorbs large amounts of CO2 as it hardens, but also requires less heating during the manufacturing process. Apparently it does this by using a different raw material, magnesium sulphate. The material is still in its trial period but bears testimony to the efforts of companies to follow, and sometimes lead, the trend to produce environmentally friendly building materials.

A chart showing how to make your home carbon neutral

A chart showing how to make your home carbon neutral

Bricks

Using recycled bricks has long been popular amongst self-builders but this can also use a lot of energy in demolishing, cleaning and transporting the bricks. The trend is now moving toward using bricks made from recycled materials and a great deal of effort is going into producing bricks that are made from materials that provide high levels of insulation, thus killing two birds with one stone (or brick).

Using stone instead of brick is being considered as one of the ways to offset the carbon footprint as it is a natural product. But it still needs to be quarried, cleaned and dressed, and is considered to be more viable if the stone is sourced locally or at worse, regionally. Part of the holistic attitude toward offsetting the impact on the environment is granting permission to quarry materials on the condition that part of the quarry site is turned into a nature reserve.

The downside to using such material could be that their inherent natural qualities don’t provide the insulation levels required to be truly effective. The other problem that arises is the lack of skill and patience required to use the material. The reality is more likely to be that each project must speak for itself when deciding on the best material to use.

Lime

Lime building has been around for more than 5,000 years, and actually predates the use of many other building materials. Used extensively by the Romans in Britain, lime has over the centuries been refined in its applications into mortars and plasters, and has undergone a revival of interest for those favouring a more natural solution to building. Lime is anti-bacterial, as well as resistant to ultra-violet light, and also allows moisture to release from the surfaces, both inside and outside. Many people wishing to build a carbon neutral home will opt to use lime in it many forms rather than concrete in its current guise, as lime also absorbs carbon dioxide.

Timber

Many eco builders are choosing to use reclaimed timbers where possible, and if structural timbers are needed, such as for roof construction, then it is possible to source from sustainable sources, and many timber merchants are working hard to follow this mandate. Where possible many are looking at the possibility of sourcing timber, or any building materials for that matter, as close to the project as possible. This method harkens back to a time when it was only possible to build your home from locally sourced materials as transporting long distances wasn’t either practical or possible.

Paint

You may have noticed that many of the paints you are buying no longer require the use of a solvent to clean the brushes. That is because new legislation is causing manufacturers of paints to remove the toxic chemicals they once used in paints from the list of ingredients. When buying your paints look for the eco labels that are now printed on the tins. They still have a long way to go in using the labels properly so a certain amount of caution is needed, but what is important is that many of the highly toxic and environmentally damaging chemicals are being removed as legislation improves.

Sourcing Local Materials

Just look around your local area and you will often see a theme running through older buildings with regard to the materials used. In Suffolk, for instance, you will find many timber-framed buildings, whereas in Norfolk there are numerous buildings constructed from flint, which could be found by just digging around the site where the building work was taking place.

Sourcing materials and labour locally also reduces the carbon footprint on transport as well as strengthening the local economy. Although there may be a higher cost, this can be offset against the reliability of sourcing materials that you have seen, and you can also cost effectively replace materials if damaged, thus not losing time on reordering.

Conclusion

There is so much more that can be said on things like sustainable design, sustainable locations, construction methods and types of construction, not to mention the various unconventional methods being used in an effort to help the environment. We will be coming back to this subject and discussing the options in more detail while at the same time offering construction advice, so watch this space.