A beginner's guide to building an eco home

Key information
  • There is no one set way to build an eco home.
  • There are numerous government schemes providing financial aid for eco-friendly fittings.
  • About 58% of a home's heat loss comes through its roof and walls.

Building an eco home continues to be one of the main ways of fighting the climate crisis. Aside from practical considerations like trying to mitigate rising energy prices and increased heating bills, making eco-friendly changes to your self-build is one of the biggest ways you can reduce your household's greenhouse gas emissions. With 35% of global energy consumption coming from buildings, eco homes and a more sparing attitude towards energy usage will be vital in the fight against climate change. If you're a self-builder trying to find a plot to design and build your dream eco home on, this guide will take you through the myriad ways to get there, some of the thought processes that underpin them and how much they might cost.                                 

Finding land for your eco home

From brownfield to greenfield, inner city or rural, the variety of plots on which you can build your dream eco home is near endless; the tough part is finding and then deciding on a plot that fulfils all your needs. Just as there's no single, set design for an eco home, there's no one type of land that is best suited to build one on. For eco homes, like normal self builds, good location, access, and topography are necessities - you can use the Addland Professional map layers to explore and plots in detail, from their ownership history to whether they lie in a flood zone. 

Eco homes are not about prescriptive rules, more a holistic approach where you do everything you can to reduce the environmental impact of your home and increase its energy efficiency: how you get there is up to you. Building on a brownfield site means you won't be disrupting the countryside, and you'll be more likely to have planning permission approved. Conversely, with a greenfield site, you could use your land to install solar panels or a ground source heat pump, both of which reduce your household's total carbon emissions. With enough land, you could also explore rewilding as a way of offsetting carbon used in construction, or orientate your house towards direct sunlight to heat your water using a solar thermal system. Whichever direction you decide to go in, it's highly recommended you explore how likely it is planning for your home will be granted - an architect will be able to design and submit all of these to the Local Planning Authority, usually charging £50 to £100 an hour. Over the whole project, you can reasonably expect to pay an architect 5-12% of the total construction cost. 

Designing and building an eco home

The fundamental aim of an eco home is to reduce energy consumption and carbon footprints, whilst being as sustainable, defined as 'the avoidance of the depletion of natural resources, in order to maintain an ecological balance', as possible. Keeping this core purpose in mind will help you understand the reasoning behind many of the measures, as well as certain government programmes. Two of the main guiding principles that eco-friendly builders and architects hold constant are:        

1) Think about the materials you're building with  

- 'Fabric first' - a way of looking at buildings that aims to improve the fabric of buildings before looking at things like alternative central heating systems or solar energy. Fabric improvements allow your house to do more, with less energy, which, in the long run, will reduce operational and maintenance costs. Though this approach may cost more initially, measures like maximising air-tightness and external wall insulation will prevent heat loss and save on your energy bills.     

- A 'carbon-neutral build' aims to reduce the greenhouse gases emitted across the building's lifespan 

On top of operational emissions, materials and construction of a building can account for half of all its lifetime carbon emissions. A more comprehensive analysis includes such things as embodied emissions, which are generated from the processing, manufacture, transport and construction of the building materials themselves. Under such an examination, it would, for example, be much more sustainable to build with local timber than marble shipped from Italy or hardwood from North America. Using sustainable materials and recycled materials, we can aim for buildings that produce far less carbon over their entire lifespans.                      

2) Make it energy efficient 

Being energy efficient is the cornerstone of every eco home's aim to reduce carbon emissions and save on annual energy bills. Thinking about your house as a closed system, the best way to make it energy efficient is to reduce the amount of energy lost through the 'building envelope': the walls, attic, windows and doors. This will decrease the amount needed in the first place: energy efficiency is, broadly, the amount of useful energy needed to meet the household's needs, minus the amount lost through the building envelope. Reducing both of these will greatly improve efficiency and lower household energy costs.   

There're a host of measures you can take: insulating your hot water pipes and hot water cylinder to window treatments to prevent heat loss. It's all about designing a home that will prevent heat leaking from where it's useful (e.g. heating your water or space) into where it's not (outside the building envelope or into cavity space). Given about 58% of a home's heat loss is through the roof and walls, one thing to think about is the quality of your insulating material. Though cheaper, lower quality insulation will take up more space and require thicker walls, taking up valuable floor space; there are numerous modern insulating materials to choose from, including natural materials. With windows, too, double glazing is a key way of reducing heat loss: modern windows have a layer of inert gas between the two panes, effectively keeping warmth inside the building envelope.        

It's not just with heat that you can be energy efficient. Using LED bulbs or energy-saving bulbs can be a great way of reducing energy use without sacrificing utility. Choosing these kinds of lights over older, more energy-intensive fittings is easily paid back - their low cost (some LEDs start at £4 each and are about 75% cheaper to run than normal incandescent bulbs) and easy installation mean you'll quickly repay the initial expense. 

One of the upsides to building your own eco-friendly house is that you can incorporate effective insulation and other eco-friendly fittings from the start, which is far cheaper than awkwardly retrofitting it in: the Government's Climate Change Committee gauge that the average retrofit costs £26,000.          

Heating your eco home with renewable energy 

Clean energy technology has, in recent times, become more and more widespread. At a national level, the proportion of the electricity grid's output generated by renewables has been going up for years, finally surpassing that generated by fossil fuels in 2020 (though this will be subject to flux as the country emerges from the COVID crisis). As a self-builder, you can take advantage of this by installing eco-friendly alternatives to traditional heating sources like gas or oil-fired boilers (the installation of which will be banned in new homes from 2025). 

Air-source heat pumps work like air conditioning in reverse, using electricity to derive warmth from the air surrounding your house. Due to the current breakdown of electricity generation in the UK, this means there'll be less carbon dioxide emissions emitted per degree of heat than if you heat your home with a traditional boiler. If you have sufficient space in your land, you can also install ground source heat pumps, which are even more efficient. Though they typically cost between £4,000 and £8,000 (without installation costs), the government has just announced the Boiler Upgrade Scheme, providing a £5,000 grant to households and self-builders looking to install heat pumps (sadly not applicable to people moving into new homes).   

Biomass boilers are a carbon-neutral way of heating your house; fuelled by wood or wood chips, the growth of the trees that produce the fuel offset the carbon emitted by the boiler as it runs. Trees, if grown and managed correctly, can also be a renewable fuel source, as well as providing numerous benefits to the environment more broadly. Costing between £5,000 and £19,000, biomass boilers are more expensive than the traditional alternatives, though if you own woodland can end being much cheaper to run. High-quality fuel is crucial to having a non-polluting biomass boiler - using wood chips made from new wood rather than waste wood helps keep down the number of toxic pollutants like hydrocarbons and benzene. This problem is more sharply felt in urban areas, and if you are located in an urban area and connected to the gas grid, you may not be eligible for subsidies to install your biomass boiler.    

Solar heating systems are another renewable alternative. If you incorporate them correctly, solar panels on your roof can be an efficient way of providing hot water. Though traditionally seen as expensive and short-lived, they can now be installed for between £4,000 and £5,000, have minimal running costs, and a lifespan of nearly 30 years. See our 'How much does it cost to build a house' guide for more information.                      

Eco home design codes

If you're looking for an end to end design code to guide you through all the minutiae of eco homes, then there are two that stand out, both of which can provide official accreditation of your self build's sustainability and energy efficiency.

- Passivhaus
Developed in Scandinavia and Germany, is a holistic, whole-building approach that aims to reduce both the environmental impact and the energy use of a building by assessing every element of said building, from position relative to the sun to type of flooring.

- The UK Code for Sustainable Homes
Introduced in 2007, aims to improve the sustainability of new homes by measuring 9 categories, from water use and CO2 emissions to how the buildings affect their occupants' health and wellbeing. All of these amalgamate into a sustainability rating from 1 to 6 stars.   

Government schemes that can help you build your eco home  

As it tries to go net-zero by 2050, the Government is committed to incentivising people to build eco homes and make eco-friendly renovations. Consequently, there are numerous schemes providing financial help to people who want to make their homes greener.                               

-Renewable Heating Incentive 
The Renewable Heating Incentive (RHI) was set up by the government to promote the use of renewable heat systems in houses across the UK. If you join up by installing a biomass boiler or a heat pump, you can receive quarterly payments for 7 years.   

- Heat pump grant
The Heat and buildings strategy, released in October 2021, has pledged £450 million to subsidise the installation of heat pumps across the UK. The government will pay a £5,000 grant to households installing a heat pump, bringing the cost down to that of a traditional gas boiler. 

- The Smart Export Guarantee (SEG)
The SEG obliges energy companies to pay households for any excess renewable energy they produce and then sell back to the grid, to be used by other people. If your eco home generates electricity through solar, wind, hydro or biogas, then you can be paid for any energy you don't use. How much, however, will be decided by your energy supplier so it might be worthwhile shopping around. 

The beauty of building your own eco home is that there are so many ways to achieve your aims. Whichever one you take, you'll need to start with a piece of land. Start your land journey today, with addland.com.  

Addland
Published: 07 December 2021
Last updated: 31 January 2022

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