Mirjam McCartney was brought up in the Alps of south Germany where many of the houses had air source heat pumps – ‘even the old ones!’ she says.
So when she and her husband Mark bought the ancient Greenacres Farmhouse in Lower Tysoe they knew exactly what to do. For the Grade II-listed house – built in two stages in 1640 and 1680 – had very little insulation and some rooms were freezing. ‘Especially as it was November when we moved in with our two boys.’
That was in 2020.
‘Our new heat pump is on 24/7 so the house is at a constant temperature and feels warm all the time. The half-metre thick stone walls retain all the heat,’ says Mirjam. ‘Just like a constantly burning log fire would have done in olden days. No highs and lows in temperature so it also prevents mould and cracks. But it’s very important that the installation is done properly. Insulation is vital.’
One of the first things they did was approach Cotswold Energy who did a heat-loss analysis for each room; this then dictated the thickness (‘not the size’) of the radiators. These differed in each room. In addition the pipes needed to be of a certain diameter. ‘Luckily ours were wide enough so we didn’t need to change them. Except for one leading to our new power shower which we did have to replace.’
She adds: ‘That’s an advantage with older homes, they usually have the required wider pipes.’
Fortunately the heritage officer had no issue with the heat pump. ‘And it’s saved us £735 a year,’ says Mirjam. ‘We run the heating, warm water and our electric car off it.’
But unfortunately he did object to their plans to open up the back of the kitchen to reach their newly planted herb garden. So, getting the renovations underway took much longer than expected. First Covid was still raging. And then the planning officer and the heritage officer often failed to see eye-to-eye.
‘He was particularly concerned about aesthetics,’ says Mirjam. ‘Whereas the planning officer was more concerned about giving new life to the property.’
With an architect and builder engaged the couple set about insulating their home.
For example in the kitchen – part of which had once been an animal pen – all the flooring had been laid straight down upon earth.
‘This was a mixture of floorboards, brick tiles and original flagstones,’ says Mirjam. ‘There were gaps in the boards so it was draughty and we frequently found dead mice. It was crucial to insulate it.’ But the heritage officer objected to their digging into the soil as he was concerned there might be archaeology beneath. ‘We live right next door to a key Civil War battlefield,’ says Mirjam. ‘But we knew the air needed to circulate beneath the floor to prevent mould. Then our architect Martin Smart (now retired) had a brilliant idea.’
They lifted all the flooring up and put in suspended trays of chicken wire filled with rock wool then covered this with a permeable membrane followed by plywood.
‘And then we laid a new floor of engineered floorboards on top,’ says Mirjam. ‘We kept some of the flagstones for our pantry and the others went inside the sitting room fireplace. Amtico flooring and carpeting were laid throughout the rest of the house.’
The slate tiled roof was in good order but they insulated it using more permeable membrane and Kingspan boards.
One of the reasons the McCartneys had bought the farmhouse was because the rooms flowed together so smoothly that no walls needed to be demolished. It also had fantastic light because many rooms faced south.
‘In fact all we did was build a stud wall to create a boot room (with Velux window) and pantry leading off the kitchen,’ she says.
The couple changed everything starting with the flooring and going right up to the roof. The only thing they didn’t change were the windows which were either double-glazed or had secondary glazing, put in by the previous owners.
They also gutted the kitchen and installed handmade and hand-painted wooden units from Monkeywood Kitchens, painted a cheerful Mister David yellow from Little, Greene. ‘They did a wonderful job seeing as no wall was straight,’ says Mirjam. ‘There was an oil-fuelled Aga there but we replaced it with an oven and induction hob. It’s inefficient to run an Aga alongside a heat pump.’
All three bathrooms and cloakroom were refitted by Burlington Bathrooms.
‘Then we had it repainted, both inside and out,’ says Mirjam. ‘Our contribution was to the garden as both Mark and I love gardening. Lucy Bravington, an award-winning designer, redesigned the entire back garden; then with gardener Simon Griffiths we put in new vegetable beds, a new shed and planted lots of fruit bushes and grasses. We kept the existing fruit trees as well as the wild strawberries. But what Mark is really proud of is his Bokashi composting system.’
This is an anaerobic process that ferments kitchen waste – including meat, dairy, and cooked foods – using inoculated bran in a sealed bucket. It rapidly breaks down waste in four-six weeks with minimal odour, producing ‘tea’ for fertilizer and nutrient-rich pre-compost that is buried in soil.
But now after all their hard work the McCartneys are on the move again. ‘Back to Oxford where we used to live,’ says Mirjam.
‘We’ve loved living in this beautiful countryside but we both have family there and we’d like to see much more of them.’.
For sale through Savills: savills.com
‘We live right next door to a key Civil War battlefield’
Address book
Monkeywood Kitchens: 01295 533413; monkeywood.co.uk
Cotswold Energy: 0333 444 5444; cotswold.energy
Paul Merrick builder, Town & Country Renovations: tncrenovations.com
Joanna Smith-Ryland: 01926 620272; joannasmith-ryland.com
Lucy Bravington Garden Design: 07855 940402; lucybravington.com
