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We are a family of four living in a 1930's semi-detached house in Cambridge, UK. Here are the steps we've taken to reduce our ecological footprint.
We are a family of four living in a 1930's semi-detached house in Cambridge, UK. Here are the steps we've taken to reduce our ecological footprint.
1. Reducing the carbon cost of heating our home
1. Reducing the carbon cost of heating our home
In 2017, my wife and I were shocked to realise that we emit a staggering ~5.5 tonnes of CO2/year to heat our home, despite having a relatively new efficient condensing gas combi boiler for central heating and hot water. This should have come as no surprise: heating is the largest energy-consuming activity in the UK (BEIS, 2017), and our heating-related emissions of 5.5 tonnes of CO2/year were about average for UK households. Over the subsequent years, we have taken the following steps to reduce our carbon emissions:
A. Insulating our home
Our home is a rather typical UK 1930's semi-detached house, with poorly-insulated external walls (single brick, no cavity). The loft had only a very thin layer of loft insulation. As a consequence, our house has always felt cold in the winter, despite fairly reasonable thermostat readings. The external walls of the house felt very cold to the touch, and the house occasionally had a damp smell during the winter months.
1. Loft insulation
A quarter of heat is lost through the roof in an uninsulated home, such that, for an average semi-detached house, ~600 kg CO2 / year (and £255) and can be saved by simply insulating the loft. Our first step was to properly insulate the loft - something we did ourselves in the, along with boarding out the loft for storage and installing a better loft hatch. This diy project cost ~£200. We placed the loft boards on 175mm loftlegs screwed to the ceiling joists to avoid compression of the fibreglass insulation, which would render it inefficient. Since then, we had a loft extension, which is also very well insulated.
2. External wall insulation
The poorly-insulated external walls of the house were built in the 1930s as 'single-skin' (no cavity) walls, cold and damp to the touch during the winter months. To address this, we comissioned a local company to apply external wall insulation (EWI) to the external side and rear walls of the house:
Our contractor, Strata Insulated Renders, applied 90mm expanded polystyrene (EPS) external wall insulation to the side and rear walls of the house, and finished with a silicone render. This job cost £7,700 but a £5000 Green Homes grant scheme voucher covered much of this cost.
Unfortunately, the Green Homes Scheme came to an end in 2021. However, a new government subsidy scheme for home insulation is due to be announced in Autumn 2022, which replaces the Green Homes scheme.
External wall insulation has had a massive impact in terms of reducing our energy usage and on the feeling of warmth in our house. Our hallway beside the side wall of our house always felt cold and damp to the touch during the winter months - this is a non-issue now.
3. Internal Wall Insulation
To preserve the front appearance of the house, we did not externally insulate the front wall, but applied internal wall insulation to the front-facing walls of the front rooms of the house (hallway, living room and bedrooms). This was a relatively straightforward and cheap job undertaken by a handyman, involving battening out the external walls, applying SuperQuilt Multifoil Thermal Insulation to these, fixing plasterboard to this, and then skimming over this. The old trim, picture rails and and covings were simply removed and placed on the new wall.
The internal wall insulation added 5 cm of thickness to the wall, so there was no noticeable loss of space to the front rooms of the house, while the rooms are noticeably warmer, more consistently warm throughout and do not have damp/mouldy spots.
Here are pictures during the internal wall insulation job (left) and after the job was finished (right):
4. Insulating drafty floorboards
Having drafty floorboards felt like having a medium-sized window fully open in the winter - chilly! Like many older houses, our floorboards on the ground floor are suspended on joists above a ventilated space on top of the ground beneath - this needs to be ventilated using air bricks in the wall to prevent condensation and damp to the joists. As a result we had very drafty floorboards, especially when windy, and in the winter, cold air would constantly vent up from beneath the floorboards so it always felt chilly, and we were wasting plenty of energy on heating.
We opted for a cheap and effective way of reducing the draughts between the floorboards - DraughtEx. This roll of flexible expansile tubing comes with an applicator (pictured to the right) which enables the DraughtEx to be applied in between the floorboards - and very effectively prevents drafts.
This has made quite a significant difference to the warmth of our ground-floor rooms. We'd thoroughly recommend this solution if you have drafty floorboards.
Here's a link to the DraughtEx website.
There are a number of more expensive options, which in addition to preventing draughts, adds a layer of thermal insulation underneath the floorboards. These include:
1. Qbot - robotic underfloor insulation!
2. Underfloor suspended insulation - here's a link to a very informative site
Essential to underfloor and other insulation is moisture control - because insulation changes the distribution of temperature it can potentially create new cold spots which condense water held in the air - causing potential damp problems. Therefore, get lots of advice from the web and/or insulation professionals before adding insulation to your home.
B. Installing an Air-source Heatpump (ASHP)
In 2021, we scrapped our gas combi boiler, and installed an Ecodan 11.2kW air-source heatpump. Heat pumps are becoming important replacements for gas boilers, and can work with the existing pipework in most water-based central heating systems.
Air-source heat pumps work by absorbing heat from outside (even on cold days) and using it to heat the house and hot water supply. The warm water generated by the air-to-water heatpump we purchased is then circulated around either central heating radiators or around a coil inside a hot water tank in the loft to heat water. Air-source heatpumps can switch between heating and hot water and therefore can be used in place of a gas combi boiler.
ASHPs transfer heat using the same vapor-compression refrigeration process used by refrigerators to transfer heat from inside the refrigerator to the outside air. Importantly, for every 1kW of electrical energy used by an Air-source heat pump to pump refrigerant gasses) ~3-6kW of heat is generated (depending on outside temperature and the temperature gradient required). Thus, 1kW of electrical energy input results in 3-6 kW energy output, and much of the heat delivered is 'renewable', having been extracted from the warmth of the outside air. Thus, whereas highly efficient condensing gas combi boilers are ~90% efficient at generating heat from the energy in the gas supplied, heat pumps can be considered 300-500% 'efficient' delivering more heat energy than the amount of energy provided as electricity. Air source heat pumps are widely adopted in many countries, including Scandinavian countries, and are gaining tremendous popularity in the UK - this will only further increase after 2025, when the UK Government brings into force a ban on installation of gas boilers in all new builds from 2025.
Our air-source heat pump was installed on a flat roof above our kitchen extension, and is remarkably quiet. Some of our existing radiators needed to be up-sized and a hot water tank was fitted in the loft. All of this was planned out and costed in a single quote by a specialist renewable heating contractor, and the job took 3 days to complete. The cost of installation was £12,000, but we were able to recoup £7,700 of this expenditure through the UK government's Renewable Heat Incentive (RHI) scheme - a sum which is now being paid back over a subsequent 7 year period.
A new scheme introduced by the UK Government called the Boiler Upgrade Scheme (BUS) has recently replaced the RHI and provides an up-front subsidy of £5,000 to assist in the installation costs of a heat pump.
The UK's electricity supply is being rapidly decarbonised, with an increasing fraction of electricity supplied originating from renewable sources such as wind and solar power. By efficiently using electrical energy to harvest the sun's energy from ambient air, heat pumps provide a powerful low-carbon way to heat homes. Installing a heat pump has dramatically reduced our carbon emissions associated with heating - likely reducing our annual CO2 emissions to approx 1.5 tonnes.
As a result of the heat pump and the insulation work to the house, we have benefitted from a much warmer and consistently heated house. Heat pumps operate most efficiently when delivering heat at a constant low temperature - as a consequence, our heat pump is almost continuously, resulting in a house that is ambiently warm. This is a great improvement over gas central heating, with scheduled warm and cool period resulting in rapid warming of air, drying of air with condensation and cold areas of uneven heat. The heat pump kept the house wonderfully warm through our first winter with it - the winter of 2021 - 2022 - with no difficulty whatsoever. Comfort, in addition to carbon emission reduction, has therefore been a major improvement resulting from the installation of the heat pump. There are also potential cost savings as the cost of gas rises due to supply issues resulting from the war in Ukraine.
2. Reducing plastic waste
2. Reducing plastic waste
A. Buying supplies from zero-waste suppliers
We have reduced our plastic waste by buying from zero-waste grocers and household suppliers.
Our favourite zero-waste household supplier in Cambridge has been Full Circle:
Full circle provides refills on oil and washing detergents, a majority of supplies are in brown paper bags, or in glass/plastic bottles and tubs that are refilled by Full Circle - and they deliver! Or you can drop by their store in central Cambridge.
Another fantastic low-waste supplier we've been using is the Good Club - which supplies throughout the UK! The Good Club delivers a variety of grains, flour, detergent, raisins, etc in reusable plastic tubs. They collect and refill these tubs when needed. AMAZING! They can be found at: https://getdizzie.com/brand/dizzie
We make bread at home using a Panasonic SD-2500 breadmaker, saving all the plastic bags used to package bread. We also routinely make yoghurt (from milk delivered in milk bottles, see below) and humous (from dried chickpeas) using an Instant Pot Duo Plus pressure cooker - creating a further quite substantial plastic saving.
B. Buying local produce from a zero-waste grocer
We get most of our groceries from Cambridge Organic Food Company which has an excellent web site for making regular orders. What you buy is highly customisable from week to week, and they deliver using electric vehicles!
Here's a link to the Cambridge Organic Food Company:
C. Glass milk bottle deliveries
We signed up for the local milk run which delivers milk in good old fashioned glass milk bottles twice per week, using an old fashioned electric milk delivery float (yes, these were commonplace in the 1980s when I grew up). With kids, we go through milk fairly fast, so this is a big plastic saving.
We also make yoghurt really easily from milk, further saving plastic use.
They even deliver orange juice...
3. Reducing the carbon cost of travel
3. Reducing the carbon cost of travel
A. Biking to work
We chose to work and live within cycling distance, making our commute fun, and good exercise. We never get stuck in traffic!
B. Transporting kids on a bike child seat, or a cargo bike!
Depending on your budget and the number of children you will be regularly transporting, this is an excellent way to transport kids to and from school, and saves on all those car journeys and getting stuck in traffic. There are a lot of options for families who need to cart kids around to school, activities and errands.
C. Reducing international travel
We have been:
1. Trying to go on holiday locally as much as possible, or in nearby European countries
2. Reducing international travel for work (for example, I have chosen to go on work conferences which are nationally held, or held in local European countries)
3. Making use of Zoom, Google docs and other internet-based tools for collaborating remotely. This has also been a game-changer for my work productivity
3. Reducing the carbon cost of food
3. Reducing the carbon cost of food
A. Going vegetarian
We were already vegetarian, however, reducing meat or going veggie is an excellent way of reducing the extensive carbon cost associated with meat production.
B. Buying in-season local produce
Avoiding flying green beans half way across the world was a no-brainer for us. We've really enjoyed the seasonality of our cooking that has resulted from buying local produce, and have broadened our palate.
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