A very unique solar solution for architect Phil Bixby

Phil Bixby is an architect who specialises in Passivhaus design. If you’re not sure what that means, we can sum it up here: he’s seriously committed to energy efficient home design. So committed, in fact, that he recently retrofitted his Victorian terrace house installing an array of vertical solar panels and a Tesla Powerwall.

Passivhaus and the impact of energy efficient homes

Just under a year ago, Phil and his partner Caroline moved into their two bedroom home in York. Phil’s architectural expertise helped them mold their new home to bring it closer to the high energy efficiency benchmarks of the German Passivhaus movement – designed to provide a high level of comfort while using minimal energy for heating or cooling.

“Passivhaus is based on principles of very high levels of insulation, very high quality external windows and doors, very high standards of air tightness and the incorporation of mechanical ventilation for heat recovery,” says Phil. “The basic thinking behind it, is that the space-heating requirements of the house or dwelling are sufficiently low that you’re much less concerned about where your energy comes from.”

According to Passivhaus Trust, buildings are responsible for 35% of total global energy consumption. That’s a big contribution to carbon emissions. Since Passivhaus buildings maintain their temperature they require very little heating and cooling - contributing not only to the UK’s transition to net zero carbon emissions, but also cheaper household bills. Cheers all round!

Combining Passivhaus design with clean energy

Phil, however, is still concerned about where his energy comes from; that’s why he’s gone one step further. By adding a solar PV system and a Tesla Powerwall, Phil made his home even more sustainable. And with the high energy efficiency design of his home, he doesn’t need to use gas for his heating.

Phil says, “The way things are going with the energy mix of the UK at the moment, it very much points you in the direction of considering electric as being a way of heating houses – and that’s what we’ve done here. While it’s not zero carbon in itself, it’s very easy to get to the level of being zero carbon by adding in renewable. Given that I’m an architect and passive house designer, I really feel like I should be walking the walk!”

And he really has walked that walk.

Turning heads with solar power

Phil’s worked with our Egg team on plenty of his client projects before, so he was well aware of our tech expertise and knew we’d be up to the challenge of his highly specialised project. 

“I’ve always used Egg because the team is always good to work with,” says Phil. “This building has a slightly unusual arrangement in that we have a south-facing gable wall where we wanted to install vertical photovoltaic panels, and a pitched roof on the back extension where we wanted in-roof installation.”

The appearance of the solar panels was a high priority, with Phil and team Egg collaborating to find ways that would incorporate them stylishly into the building’s facade. After all, who said clean energy can’t look good?

“I got the team to run some calculations on how effective the panels would be on the gable wall,” says Phil. “They showed fairly healthy numbers so we went for that. We finished it with some matching trim round the edges so it all looks like a nice dark grey wall that just so happens to have solar panels within it.”

“For the installation on the back extension roof, we stripped all the slates off, put the solar panels up and then tucked the slates in to make it all look good. It gets quite a bit of attention – my office looks out onto the street so I occasionally get people peering through the window saying ‘Are those solar panels up there?’”

Making clean energy storage a focal point

The solar panels aren’t the only attention-grabbing element of Phil’s super-efficient home. He had one particularly offbeat request that was an absolute first for us.

“We wanted our Tesla Powerwall up on the dining room wall,” says Phil. “Partly that’s because I’m an energy nerd, and if it’s going to give any heat off, I’d rather have that be inside the house – so we’re actually getting the benefit of that in winter. But partly it was because I quite like having it in the house so I can peer at it! People come in and see Tesla written across it, and everyone goes “Ooooooh!” in that way that they do, so I talk them through what it is.”

Combined with his solar panels, the Tesla Powerwall stores the solar energy that isn’t used immediately in Phil’s house. 

The impact of Phil’s energy efficient home  

Talking to Phil it takes no time at all to answer the key question, was it a success? 

The answer is a resounding yes. The passivhaus retrofit alone made Phil’s home 5 times more efficient, so it already takes significantly less energy to heat than the average home.

All of Phil’s heating is handled electrically with a post heater in the ventilation system, warming fresh air that’s then pumped into the house. Electric towel rails and 1.5k of electric underfloor heating are the only other form of heating in the whole house. Impressively, there’s no gas heating needed at all.

“At the moment, as it’s summer, we’re not using any heating,” says Phil, “but we’ve got a whole house-worth of domestic, plus my office running on the solar and the Powerwall. Quite often we’re running on no imported electricity at all, and are actually net-exporting much of the time.

“The worst case in winter for our place here is around 30-40kWh of electricity bought from the grid per day,” says Phil – a saving of up to 18kWh compared to the UK’s national average for daily consumption in winter. On top of that, Phil made sure when selecting his energy provider that he could select a tariff that would allow him to programme his Powerwall to charge up with cheaper energy at night when needed.

“The Powerwall will check ahead, work out if the weather’s going to be bad the next day, and if it is then it’ll charge up overnight,” says Phil.

The financial saving from clean energy

With Phil’s office located in his house, both he and Caroline are at home 24 hours a day, 7 days a week. They’re using electricity for food, warmth and running an electric bicycle. Even though they’re spending a lot of time in their home, with their solar panels and Powerwall working together, they’re making some major savings on their energy bills.

“I’m still waiting for a full year’s worth of figures on it,” says Phil, “but we’re looking like somewhere between 33% and 50% of our energy coming from solar. It looks like our overall energy bills will probably be somewhere around £700 a year.”

Feeling just a little smug for all the right reasons

Of course, making a significant financial saving on household running costs must feel pretty good. But perhaps the biggest impact of Phil’s energy-efficient home, renewable generation and battery storage, however, is emotional: the warm, fuzzy feeling he gets from being energy independent and minimising his carbon footprint.

“Smugness is the word, really,” says Phil, laughing. “No, this has actually very much been a joint journey with my partner Caroline, in terms of designing the place and how we want it to work. She has no particular involvement in design or architecture, but she’s absolutely in love with our home because it’s such a pleasant place to live. The house just chugs along comfortably without us really needing to do anything, and we have the knowledge that I can easily report on a regular basis ‘Oooh, look! We’ve only used “x” amount of electricity in the last however many months.

“I regularly tap the device on the wall in the kitchen just to see what the system’s doing, and it’s a nice feeling knowing that we’re able to live comfortably without burning any gas or using huge quantities of electricity from the grid.”

The future of carbon zero home living

If you want an example of what next-level sustainable living looks like, look no further than Phil. Bringing together the philosophy of Passivhaus energy efficiency with solar panels and battery storage, Phil’s home is as close to zero carbon as you can get.

Whether you’re ready to make some significant changes to reduce your carbon footprint like Phil, or you’re taking small steps that contribute to a big impact, our team at Egg are here to help. 

You can find out more about adding a solar power system with battery storage to your home here.