Our desire to turn our three-bedroom semi into an eco home was driven by profit. My wife and I hoped that investing in a heat pump, smart battery and every other green technology would result in lower bills for decades to come. Of course, with ten-year-old twins and a seven-year-old, saving the planet came a close second in our equation.
Our profit-first reasoning was that installation costs appear to have reached a tipping point. For example, electricity prices keep rising, while the cost of solar panels has decreased by more than 70 per cent in a decade.
On paper our plan sounded sensible. As optimistic novice renovators, we can share two serious downsides. The first is the level of research required. To incorporate underfloor heating, boiling water taps and a water tank using phase change material in a house built in 1924 was like completing a 10,000-piece jigsaw while drunk. Problem-solving became a daily puzzle.
Rutherford estimates their renovation cost £30,000 extra due to the eco-friendly tech they chose
PETER FURLONG
The second downside? We spent an absolute packet. Perhaps £30,000 more than if we had renovated without the green tech. This fact was clear during our frigid nadir when — to save money — we lived through winter inside our builder’s caravan parked on my mother’s driveway. A claustrophobic purgatory.
Was it worth it? Top-notch insulation means we don’t turn on the heating from March to October. Solar power, in tandem with our energy-saving initiatives, means we won’t receive an electricity bill for decades. In fact, we are £847 in credit with Octopus Energy.
Our house’s value is undoubtedly higher too. Moving from an EPC rating of F to C could improve a property’s value by up 15 per cent, Rightmove’s Greener Homes report suggests.
As our breakdown for each green investment shows, our tech will eventually pay for itself.
1. Solar panels
Solar technology has become so efficient at absorbing energy from the sun that we needed panels on only half our roof to create a 12kW solar farm. An app predicted the best placement of our Aiko Neostar 455W panels, as well as their return on investment. In June 2025 we generated more than 1,500kWh of electricity and consumed 500kWh; our unused juice was sold directly to the grid for a £200 profit.
Rutherford admires his home’s array of solar panels
KATHRYN TOMASETTI
“A high-capacity array like Tristan’s lets his family earn from surplus power, with the potential to offset their entire winter energy bill,” says our installer, Neil Whitfield of Solar Store. “Hardware prices have fallen so a renewable-powered home is in more people’s grasp.”
Cost: About £8,500 for 27 panels, wiring, inverter and installation.
Saving: Combined with our smart battery, our electricity account is credited with more than £100 a month from May to September.
2. Smart battery
The energy-bill killer. Our 10kWh domestic batteries from Fox ESS, the UK’s most popular brand, can automatically charge with electricity when tariffs are low, then sell energy back to the grid after work, when every Briton turns on their oven. We also run all our appliances when electricity prices are lowest.
The battery optimisation company Capture Energy says that its average customer reports at least a 50 per cent reduction in electricity charges, with many customers seeing zero or negative bills. “And at times of excess generation, like on extremely windy or sunny days, wholesale electricity prices go negative,” adds Capture’s co-founder Clemens Munter. “This means that energy suppliers actually pay battery owners like Tristan to fill their batteries for free.” Munter calculates the return on investment period for a smart battery like mine is about three to five years.
Cost: About £3,500 including installation.
Saving: Battery owners report a 50 per cent reduction in yearly bills.
3. Passive solar gain
Our rebuild was designed by the architect Resi to deliver one gigantic 700 sq ft living room, which we use for film location shoots for Netflix and ITV (@modernfilmlocation_midlands). Resi also created an upstairs textile studio for my wife, who grows traditional dye plants in our garden, uses them to colour reclaimed fibres, then handweaves them into scarves and baby wraps (@botanicalweaves).
Rutherford’s open-plan kitchen/living space is used for TV and film shoots
PETER FURLONG
Our architect’s secondary brief was to trap thermal energy from our south-facing home. It recommended 5m-wide sliding doors and a 2m-long roof lantern. “All Resi clients are offered free retrofit advice [for solar, windows, batteries and the like] because we have a commitment to cutting energy costs,” says Oliver Winston Burgess, the architect’s head of design. “Specifically for Tristan and Kathryn, we recommended high-efficiency (low-emissivity) glazing to enable passive solar gain, which lets in sunlight to heat internal spaces.”
Cost: When we replaced all our windows, the upgrade to A+ efficiency glazing cost about £1,200 extra.
Saving: Probably £100 annually in energy savings.
4. Underfloor heating
Forget cost-saving. This was our number one desire for sheer cosiness. Padding barefoot across a warm floor in deep winter is a delight. Also, underfloor heating means no cold spots and no wall-mounted radiators, so owners can place furniture wherever they like.
Underfloor heating delivers the best bang for your buck when the pipes are covered by solid concrete. “[Concrete] takes longer to heat up and cool down,” says Brian Horne, technical knowledge lead at Energy Saving Trust. “This results in a more consistent release of heat, making it well suited to a heat pump.” We couldn’t afford carpets so we simply painted our self-level flooring with OSMO concrete oil. The finish is similar to a polished concrete floor.
As underfloor heating operates at a lower temperature than standard radiators, running costs are lower. Horne says: “It’s impossible to pinpoint exactly how much underfloor heating contributes to efficiency.” However our heating bills are about 40 per cent lower than they were pre-renovation, for double the interior space, albeit with much better insulation.
Cost: About £5,500 for plastic underfloor piping, programmable thermostats and installation.
Saving: Our previous £2,500 annual heating bill has been snipped by about £1,000.
• Read more expert advice on property, interiors and home improvement
Kathryn’s textile studio
PETER FURLONG
5. Heat pump
Our underfloor heating is powered by a 9kW Daikin heat pump. Pumps transfer heat from outside, rather than creating warmth, making the process ultra efficient. For every 1 kWh of electricity used, a heat pump can deliver 3-4 kWh of heat.
The game changer is to use a pump-friendly tariff such as Cosy Octopus, where owners purchase discounted energy when the grid is under-utilised, for example from 4am to 7am. Heat pumps work well with lower temperature applications such as underfloor heating but can power radiators too.
The family hopes their eco renovation will eventually pay for itself in energy savings
PETER FURLONG
Best of all, heat pumps come with a massive grant. “All homeowners in England and Wales can take advantage of the Boiler Upgrade Scheme, which gives you £7,500 towards the cost of [upgrading from traditional heating] to an air or ground source heat pump,” says Clare Casalis, senior energy and utilities analyst at MoneySavingExpert.
MoneySavingExpert also gave us energy saving tips, including lowering our fridge’s Arctic-like default settings and choosing LED bulbs.
Cost: £10,000 for heat pump and installation, minus the £7,500 grant.
Saving: Our architect, Resi, suggests a £465 a year saving for a three-person household.
6. Composting and homegrown vegetables
While living The Good Life won’t pay our mortgage, we determined that building raised vegetable beds would shave hundreds off an annual food bill for a family of five. In our first year we spent £120 on bags of compost. Now we now produce two cubic metres a year by composting vegetable peelings, coffee grounds and torn-up copies of The Sunday Times.
Composting at home can reduce food costs
ALAMY
• How to make a compost bin at home
“Homemade compost has a far higher value than any you can buy, because of its microbial colonisation,” says the gardening expert Charles Dowding, who pioneered the no-dig vegetable-growing method. “Even in large containers you can grow a decent amount of salad leaves, carrots, herbs and spring onions.”
One caveat: labour costs. When calculated in man-hours, the effort we put into growing 15 organic cucumbers this summer meant each cost about £20. “The value is not only monetary,” Dowding says, “but also what it brings to your health and wellbeing.”
Cost: £150 for three compost bins.
Saving: About £300 a year in reduced food costs.
7. Water tank with phase change material
Remember those hand warmers that heat up when you break a capsule inside? A hot water cylinder with phase change material works in a similar way. When our tank is charged, an element inside changes from solid to liquid, storing the heat. Research suggests the process is more than four times more efficient than storing heat in water.
“It takes 30 minutes to charge Tristan’s Daikin tank compared with four hours for a traditional immersion tank, to produce the same amount of hot water,” says Stuart Jones from Live Manage Facilitate, who installed our system. Our tank is far smaller too. Hot water is instantaneous, with none of the revving hum a gas boiler makes when you turn on the tap.
Cost: £500 more than a standard hot water tank.
Saving: About £100 per year in hot water costs.
8. Insulation
Our most invisible, expensive, yet noteworthy investment. The majority of our loft conversion, plus new and existing walls, was cladded with 100mm-thick polyisocyanurate insulation boards made by Celotex. The heat retention, when compared to the 1970s home I grew up in, is unfathomable.
Renewable energy companies such as E.ON Next support the Great British Insulation Scheme. The grant offers some homeowners and renters £1 billion of free insulation funding. “It only takes a few minutes to check eligibility for GBIS online,” says Ramona Vlasiu, chief operating officer for E.ON Next. The cavity wall and loft insulations it supports can be installed in one day.
Cost: About £15,000, although we needed to insulate our renovation from scratch anyway.
Saving: A semi-detached home could save up to £470 annually on average, according to the Energy Saving Trust.
9. Quooker tap
The average Briton spends six months of their lifetime waiting for a kettle to boil. With a Quooker boiling-water tap, my kids can indulge their love of Bovril, miso soup and Itsu instant noodles without the wait. “Because a Quooker only dispenses the exact amount of boiling water needed, it avoids the waste you get from kettles,” says the company’s managing director, Stephen Johnson. Quooker taps use 10W on standby, “about the same as a low-energy lightbulb”.
Rutherford’s Quooker tap
KATHRYN TOMASETTI
Cost savings are instantaneous. “In energy terms, families can cut boiling costs by up to 50 per cent compared with a kettle,” Johnson says.
Cost: £1,050.
Saving: About £50 annually based on our family boiling a kettle ten times a day.
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