Saving the planet, one greener house at a time

Our green family adventure began in 2005, when we decided to swap our gloomy contemplation of unstoppable climate change and our individual feelings of powerlessness in the face of it, for a plan to save the planet, one greener house at a time.

We are a family of four (Anne, Rob, Caitriona and Conor), living in a medium-sized house built in 1963 with little thought to saving the planet. Our timing coincided with our children (now 20 and 14) being old enough to either join in or to entertain themselves safely nearby. It was a bit daunting to get started, but we found that once we started with the easier stuff, the first guilt-free moments, eg watering the garden and kids’ water-fights from the rainwater butt, gave it all a sense of momentum that gave us the energy (!) to keep going.

Our efforts have focused on three main areas: insulation, clean energy generation, and water conservation. The results to date have included substantial improvements in all three, a big reduction in our carbon footprint and a more comfortable home in winter and summer. Our 10 top tips for where to start are listed below. But first, the adventure itself.

It’s often been quite a lot of hard work, but this has been an excellent antidote to our day jobs, often outdoors, with a lot of fun and a great sense of achievement for all of us. Rob is an electronic engineer and is also very competent at DIY, so will always have a go if legally allowed to do so, and we have all now learned a wide range of DIY skills. He likes the 'techy' side of measuring energy consumption and its encouraging downward trend over the years. As a scientist, I’m also impressed by the data. We started with cavity wall insulation, which was done professionally. Our own DIY efforts started with a water butt and loft floor insulation when Caitriona was 4 or 5, then it all stopped a year later when her brother was born, until he was 3 or 4 years old. We then embarked on draught-sealing everywhere, changing our windows to triple glazed, solar panels for electricity and water heating, grey water toilet, heat exchanger and external wall insulation. Our children have found the journey very entertaining since it frequently included legitimate ‘messy play’ and have usually been enthusiastic to help. Their favourite activities have been squirting foam and polystyrene beads in gaps under floorboards and windowsills, playing hide and seek in DIY stores, and now they’re older, climbing on the scaffolding to cement on external wall insulation, and taking guilt-free hot showers.

Caitriona contributed a cartoon when she was 7, that we still have in our downstairs loo, which reads ‘turn taps off or you’ll be murdering nature’, which we hope is an amusing message for visitors. There have been scary moments. DIY prising the glass panes out of our double-glazed windows and replacing them with triple-glazed alternatives was a bit nerve-wracking since it relied on very accurate glass measuring, but it all worked out fine in the end.  

We all have our own favourite outcomes. My own has been saving water through the downstairs grey water toilet. By means of a pipe running from the upstairs bath, shower water is stored in the cistern for use in flushing. Caitriona’s is the guilt-free hot showers provided for half the year by the two solar water heating panels, while Conor loves the often overlooked and misunderstood flip side of insulation, which is that it actually also keeps the house cool in summer! This is helped by one of Rob’s favourite gadgets, the heat exchanger, which keeps humidity at an optimal 50%. We’ve all been very grateful for these in recent summers when outside temps were in the mid-30s and the house always stayed below 22°C.

A really fun part of the adventure has been our involvement with the annual Cambridge Open EcoHomes exhibition. In September each year, volunteers write a description of their house-greening efforts and people drop in at selected weekends to have a look. This showed us that there are many willing and enthusiastic people out there at different stages, with varying skills and budgets, but who all want to make a difference in this way.  Our own EcoHome description from 2017 includes all the technical details of what we’ve done, including costs, and measurements of energy and water use and carbon generation, all of which have reduced by 50% to 75% in that timeframe. There are also some good general beginners’ tips in this beginner’s guide.

More recently, our major project has been external wall insulation (EWI). We have covered the house ourselves with 150mm platinum external insulation panels, and it has been professionally rendered (waiting on the front of the house to be finished). This winter of 2020/21, with EWI covering the house, and all four of us working from home, we have all noticed a big difference. Apart from an hour in the morning, we have not had to have the heating on at all during the day, except for two of the coldest days. The previous winter, we would have put the heating on for a few hours during the day if working from home.

What’s next? Probably an external heat pump and insulating the garage roof. Our ultimate goal? We already have a net zero cost for gas and electricity, which is great, but our ultimate aim is to make the house insulated enough to switch off our gas-powered central heating altogether. This now looks achievable, and is very exciting as it means our net carbon footprint will be close to zero. Though as scientists and engineers, we’ll do a trial experiment first before sealing up that gas pipe. 

Our 10 top tips for the simplest to more complex or expensive renovations (in roughly the order in which we did them) would be:

1. Gauge energy usage. Take readings from gas and electricity meter every month and plot month by month. This shows your seasonal variations over a year and will be a good starting point to see what difference any changes make. You should see a big difference with cavity wall and loft insulation.
2. Cavity wall fill - pay a company to fit this.  Cambridgeshire is a very dry region, so very suitable.
3. Loft insulation at joist (floor beam) level. Companies will do this, or DIY. More loft insulation - fit "loft stilts" to joists, and loft boards over the top.
4. Air Leakage – seal skirtings, window-frames, kitchen/bathroom pipe exits. Use "backer rods" in downstairs ventilated floorboards. 
5. Theoretically calculate all heat losses. Thermal transmittance (U-value) of floors, walls etc is explained in link below. The lower the better.  Estimate hot water use, have a "blower door test". Buy a humidity&CO2 meter (eg Kecheer CO2 detector).  This helps indicate where next to direct attention.
6. Loft insulation at rafter level (ensure 50mm gap to tiles for ventilation)
7. Windows - improve glass if needed (double/triple glazing), if replacing unit use 3G.  "Old" double glazing has a U-value of 2.7, new is 1.0.
8. Solar panels: PV (Solar PhotoVoltaic). These need a professional to fit. To help financially get an electricity provider that pays for the excess electricity. Spare electricity can be directed to heat hot water. During the summer we generate 3.5 Mw/h, vastly in excess of our needs.
9. Heat exchanger. Replaces air in the house with fresh air without losing the energy. Importantly also regulates humidity, good for avoiding infections.
10. Solar Thermal – needs professional fit (RHI payments available) or DIY (cheaper, but no payments)
11. External Wall Insulation (EWI)

Many of these improvements can now be part-funded (up to two thirds of the cost, maximum £5000) by the Green Homes Grant.

Finally our best top tip: ask others for advice. It’s not possible to give enough detail in a blog, but those who have been on this adventure for a while are usually very enthusiastic about passing on their experience to help save the planet, another greener house at a time! Indeed, we are very happy to chat about about/advise on anything we’ve mentioned above. Just email me at anne.corcoran@babraham.ac.uk  (with Green House in the title).