Passivhaus: The Energy Efficiency Podcast – episode 2


Welcome to Passivhaus: The Energy Efficiency Podcast, episode 2, the podcast that brings you a mix of energy efficiency news, products and tips all year round. We’re interested in profiling people and products involved in promoting energy efficiency habits, products and information, so please do get in touch if you have something to contribute.


A passivhaus in Darmstadt

If you’re interested in energy efficiency chances are you’ve heard of passivhaus. In very simple terms passivhaus is an airtightness standard achieved through high-performance windows, doors and other danger zones together with very high levels of insulation and efficient heating systems. The certification can be applied to whole buildings, specific components such as windows, and the architects and tradespeople involved in the design and build. Rigorous testing is carried out before anything or anyone involved can be designated to have met the required standard.

As a guide, a passivhaus building will have excellent insulation, low-energy services and require very low levels of energy to keep at a comfortable temperature. In the UK building regulations typically require a level of insulation and energy efficiency far lower than passivhaus, and within that standards vary across England, Scotland and Wales, and differ between domestic and non-domestic buildings.


However some organisations in the UK are building to passivhaus standards. They clearly recognise the benefits of keeping buildings at a comfortable draught-free temperature at a low energy cost. Exeter City Council is one. For the last 10 years all new council buildings in Exter, both residential and commercial, are very low energy (meeting passivhaus standard), healthy (meeting the German Building Biology principles), climate ready and set within a sustainable landscape. The Association for Public Service Excellence has this to say:

“These buildings are healthy for residents and occupants, comfortable regardless of the weather and extremely cost effective to run (thereby helping to eradicate fuel poverty). From a Council perspective we have reduced operating and lifecycle building costs, happier and healthier tenants with reduced rent arrears and anti-social behaviour and exemplar buildings that are performing way beyond comparable building regulation compliant assets.”

But what do you have to do to create buildings operating to such high energy efficiency standards? It comes down to reducing heat loss, maximising the effect of passive sources of heating such as sun, body warmth and extracted or emitted heat from household appliances, and making up any shortfall with low energy heating systems. The Passivhaus Institute describes it as

“A Passivhaus is a building in which thermal comfort can be achieved solely by post-heating or post-cooling the fresh air flow required for a good indoor air quality, without the need for additional recirculation of air.”

High standards

This can be a very complex process requiring expensive high-performance elements such as triple-glazed windows and a mechanical ventilation system with efficient heat recovery; extremely detailed planning; and specialist builders and fitters.

It’s not feasible in many cases of renovating an existing property, in which case EnerPHit can be a more appropriate standard to aspire to. This is a slightly less exacting standard designed for renovations, particularly where the architecture of the building needs to be conserved. Improving the energy efficiency of historic buildings without causing more problems than you solve is something we will look at in a future episode.


A Victorian house

The UK has one of the highest proportions of pre-WWII domestic buildings in Europe. Unsurprisingly old and inefficient buildings have been identified as one of the biggest contributors to energy wastage in the EU.

The EU has identified energy efficiency as one of the pillars of its policy response to addressing the challenges of climate change and the reduction of greenhouse gas emissions. There is an EU-funded PDF brochure available titled EuroPHit: Increasing the European Potential, Implementing deep energy step-by-step retrofits. The link will be in the show notes. It discusses passivhaus and the scientifically-quantified benefits of the passivhaus standard.

EnerPHit benefits from the passivhaus expertise that is available in the UK and beyond. While accepting that it’s not possible to reach such high standards, working with passivhaus principles in an EnerPHit project will dramatically improve the energy performance of an older house. The Passivhaus Trust website includes a number of case studies of both social and private housing, commercial buildings and educational settings, which have undergone renovations aimed at achieving EnerPHit standards.

EnerPHit focusses on improving the energy performance of the fabric of a building while accepting that many aspects of a building are fixed: location, orientation and often a thermal bridge or two that just can’t be eradicated. According to the magazine Homebuilding & Renovating:

“To achieve EnerPHit you must achieve:

A space heating and cooling demand of 25kWh/m2/year (compared to the Passivhaus standard of 15kWh/m2/year)
Instead of an airtightness performance of 0.6 air changes per hour you need to achieve 1.0 (the Building Regs for new homes require between 5 and 15 according to the Chartered Institution of Building Services Engineers)”

Deep works

To achieve these sorts of figures, though not as rigorous as passivhaus standards, can still be a huge undertaking. It can involve digging out floors and replacing roofs, all within the confines of an existing build. In this situation even more perhaps than for a new build, an expert and very well-informed design team is crucial. The Homebuilding & Renovating article is very informative, so if you’re considering deep energy efficiency work on an existing build it’s very worth while reading.

Open Days

Every year the UK Passivhaus organisation puts on the UK Passivhaus Open Days, as part of the International Passivhaus Open Days. This year it’s running the weekend of 28th-30th June, and details can be found at

Community Projects

The Petflap on red

Most people won’t undertake a large scale project to build or retrofit a house to passivhaus or EnerPHit standards. Many people will make some changes, install items such as a Chimney Sheep or a Petflap draughtproof pet door, hang a curtain over the front door or maybe replace a boiler.


Many households have neither the budget nor the scope to make any improvements. It’s in this situation that community groups can provide an invaluable service. They offer advice, subsidised services and products, and in some cases obtain grants. Plymouth Energy Community – PEC – is one of these organisations. In 2016 it received £500,000 from the Big Lottery Fund for a four-year project to help disabled people stay warm, well and comfortable in their homes.

The problems most commonly encountered were issues with the building fabric – poor insulation and black mould for example – but also problems paying bills and a lack of understanding of how to get the best deal from an energy supplier. PEC visits people in their homes. It advises on the best energy deal and how to use energy efficiently, and looks at how the household could benefit from grants and schemes such as the Warm Home Discount Scheme.

The Warm Home Discount Scheme

The Warm Home Discount Scheme is a government initiative open to people in receipt of specific pension top-ups, and those on a low income who qualify for their supplier’s criteria for the scheme. There’s potential for up to £140 off an electricity bill that comes in the form of a discount off the bill rather than as a payment.

These and other grants and schemes can be complex to apply for, so the assistance of groups such as PEC is very welcome and makes a real difference to those it reaches. The Royal Borough of Kensington and Chelsea runs a similar scheme under the title Homes4Health, focussing on the poor health outcomes of living in a damp home, such as respiratory and circulatory problems. This free service is delivered by the environmental charity Groundwork London, and aims to reach young families, elderly residents and those with multiple health conditions. The range of services offered by Groundwork London through this scheme is impressive and wide-ranging. It includes practical help such as installing small draughtproofing measures.

There are similar schemes run all over the UK so if you or someone you know could benefit search up something like “warm homes energy efficiency” with your location and see what comes up.

Thermal imaging

The magnificently-named C>H>E>E>S>E project in Bristol is doing something different from many community projects. It conducts thermal imaging of a home from low-cost to no-cost depending on a household’s circumstances. A clear understanding of a building’s thermal performance is essential if works to the home are going to focus in the right and most cost-effective places. CHEESE’s work typically shows up poorly-fitting windows, missing insulation and draughts between floorboards. These can all make a home feel uncomfortable in cool or damp weather.

Generating power

Not all community energy efficiency projects focus on home improvement and help to pay bills. Some schemes actually generate the energy. There’s a list of projects on the Community Energy England website. Back to Plymouth, a solar array has been built on derilict land, providing enough clean energy for 1000 homes. This is an excellent use of derilict or brownfield sites. The project is forecast to provide a community benefit fund of approximately £2,900,000 to support PEC’s grassroots work.

In Talybont on Usk a group is generating hydroelectricity for the community. This first community hydro scheme in Wales runs a 36kW hydro electric turbine off the compensation flow from Talybont Reservoir. Since launching in 2006 the group has diversified into a community eco car share scheme that runs one electric van, and a car running on recycled vegetable oil. The group has also installed PV panels on the community hall roof which helps cover the hall’s running costs and powers the community electric car. The group continues to develop and looks to be a great example of what can be achieved.

A project straddling the two community energy efficiency models is Energise Barnsley, which has installed free solar PV panels on the roofs of over 300 council-owned homes. The majority of these homes are bungalows with elderly residents. A proportion of them are on pre-payment meters. The residents benefit from savings through the use of a solar electricity monitor which indicates when the solar panels are generating and so when they can use free electricity. So far residents have saved over £40,000 and reduced carbon emissions by 400 tonnes. Schools, sheltered housing and community buildings in Barnsley have also had the panels installed. This makes the combined size of the portfolio the largest UK community energy project by the number of roofs installed on.


Reading up on the projects listed, it’s clear that starting up a wind, solar or hydro project is a slow and complex process requiring various funding streams, feasibility studies and often planning permission. Many projects listed are great ideas but are only part- way through this process.

The UK Energy Research Centre – UKERC – website says that although exact numbers aren’t available, it’s estimated there are about 300 small energy generation schemes in the UK. The sector was going at a great pace until recent political changes reduced support for schemes of this sort through changes to the feed in tariffs. This has slowed down development.

However a press release on the UK Power Networks website states that community energy is powering thousands of homes in the South East, East of England and London, according to a newly published report into local generation with Community Energy England and Community Energy South. The majority of community electricity generation in the region comes from two solar farms owned by Orchard Community Energy in Kent and Meadow Blue Energy in West Sussex. They generate 10.4 MW between them. This is very encouraging and we hope to see more good news of this nature.

Smart Meters

Smart meters have for a few years now been hailed as the solution to energy wastage. We must all have seen a friend very excited by the new monitor and turning off appliances they had previously hardly considered. This tends to be a flurry of enthusiasm in the early days, then normal service is resumed. The reality is that smart meters themselves do nothing to reduce a building’s energy usage. They can draw attention to the most energy-hungry items and allow the householder to make a judgment to discard, turn off or upgrade an item but ultimately this human effort is what makes the difference. Smart meters can lull the homeowner into a false sense of security of having ‘done something’, when actually nothing will change without their input.

Changing habits

Depending on what you read, smart meters are a fad, are here to stay, will save half a billion a year or reduce your annual bill by about a tenner. Clearly smart meters divide opinion. According to a Which report on smart meters:

“34% of smart meter owners think their gas and electricity use has reduced since they had a smart meter installed. In contrast, 20% of smart meter owners think theirs has increased.”

The rest don’t think anything’s changed. It seems installing a smart meter is most likely to lead to savings if the homeowner has requested one, ie the individual was already aware of energy efficiency and wanted a tool to help them best achieve it, so the willingness to work with the meter was there in the first place.

Widespread installation

The government would like all homes to have a smart meter installed by 2020. There’s no obligation and anyone has the right to refuse. Seeing smart meters in all homes is part of the process of developing a ‘smart grid’. This smart grid would allow for more efficient matching of supply and demand. Balancing this is a headache for the industry at the moment.

Installing smart meters widely should remove the need for estimated bills and getting into a cobwebby dark and awkward corner with a torch to read the meter. Some energy suppliers offer so-called agile tariffs which display energy prices via the smart meter on an eg half-hourly basis. A householder can then use energy when it’s cheapest. On the other hand, the cost of installing a smart meter in every home adds something to the bill.


Some earlier meters have lost functionality when the householder has switched supplier but this can be fixed by a wireless update. Failing that the energy supplier is required to fit a new meter.

According to the Octopus Energy website:

“As of March 15 2019, SMETS1 meters are no longer Ofgem compliant.”

They go on to explain that there’s only limited SMETS2 stock available in the UK currently. Reading around energy suppliers’ websites, it’s clear that they have reservations and are holding back on full scale installation to monitor smart meter performance and problems.

These problems seem not to be going away any time soon. According to The Independent:

“Energy giant SSE agreed to donate £700,000 to the official fund for supporting vulnerable bill payers this week after failing to meet obligatory smart gas meter installation targets. It’s the latest in a series of hits, delays and, ironically, spiralling bills to have plagued the much-vaunted smart meter rollout, designed to deliver cost-saving technology to 30 million homes and small businesses by 2020.”

The article goes on to quote Smart Energy GB, the agency promoting smart meters. It said that of 2000 people polled more than a third said they would be more likely to buy an electric vehicle (EV) if they could use their smart meter to programme charging for the cheapest periods. EV use could play a key role in promoting enthusiasm for smart meters in the home.

So far the greatest benefit of smart meter roll out is as much for the benefit of the energy suppliers and the national grid as it is for the customer. The ball is in the companies’ court to help householders understand how to get the best from their meters.

Energy saving product of the week

This week’s energy saving product is another simple but effective idea. Radflek Radiator Reflectors are laminated aluminium foil panels that sit against the walls behind your radiators. They reflect back into the room heat that would otherwise be wasted against an external wall. Tests showed that Radflek reduced heat transfer through walls by 45%

Radflek’s website claims that it reflects 95% of wasted heat back into your room, really exceptional performance. We like the idea of these reflectors because they prevent waste, one of our top aims, but like our products they are fit-and-forget solutions. The panel stays in place all year round and whenever your heating comes on it will start doing its job immediately.

At an affordable price of around £20 for six panels, Radflek expects to pay for itself in a year or so. The panels go on for years so you make savings every year. Added to that, Radflek’s site describes the product as visually unobtrusive, easy to fit and requiring no DIY skills. For the final seal of approval, The Energy Saving Trust recommends Radflek Radiator Reflectors.

Richard’s Energy Saving tip of the week

If you want to fit insulation to parts of your house but have only a small budget, not enough to fit out a whole room or house, you will get the maximum effect for your money by insulating the walls from the ceiling down. This prevents the warm air that rises in a room from chilling down as much as it would in a room without insulation at the higher levels. Together with the thermostat ledge tip in last week’s episode, this will help you keep warmer for less outlay and get the best from your thermostat.

Letterplate Eco

What are we up to? We’re still in flux while we work with new kit, and we’re expecting samples to arrive soon from a new manufacturing partner. While keeping a close eye on quality and always looking at ways to make our manufacturing as quick and simple as possible, we are looking to work with partners as much as we can. This is how we will increase manufacturing volume and bring the Letterplate Eco to market as soon as we can.

Thank you for listening. Search for Ecoflap on Twitter and Instagram to keep up with us until next time. Next week we’ll be talking about energy efficiency in historic buildings, energy efficiency across the world and sustainability in the construction industry. We are lining up a couple of interviews for future episodes, and as always we’re keen to hear about energy efficiency initiatives, projects and products, so please do get in touch if you have something to contribute. Until next time.

“Werq” Kevin MacLeod (
Licensed under Creative Commons: By Attribution 3.0 License

UK Renewables: The Energy Efficiency Podcast – episode 1

UK Renewables

Welcome to UK Renewables: The Energy Efficiency Podcast, episode 1, the podcast that brings you a mix of energy efficiency news, products and tips all year round. We’re interested in profiling people and products involved in promoting energy efficiency habits, products and information, so please do get in touch if you have something to contribute.

UK Renewables

uk renewables
Wind farm

At the end of May the UK press was widely trumpeting the fact that Britain (without Northern Ireland) had managed to power itself for two weeks without burning any coal. Since April the periods without burning any coal had lengthened, from 90 hours, to a week, to two weeks. At the same time, on one day a quarter of Britain’s needs was met by UK renewables in the form of solar energy alone.

Renewable UK, the renewable energy trade association, states that half of UK renewables comes from wind power, something in which the UK has been a pioneer and which continues to grow.

Other fuels

It’s important to bear in mind that not all non-coal power comes from UK renewables. Nuclear and gas play a part. It’s also the case that some of Britain’s coal-fired power stations were always on their way out. They are outdated and/or fail to meet European regulations on acid rain.

The government has done something to support solar and wind installation through subsidies, but it’s carbon pricing that has really seen gas become more attractive than coal as it emits less carbon. This merely swaps one fossil fuel for another. Switching from a position of using 100% coal for power production to 100% UK renewables was always going to be a circuitous journey.

Julian Leslie of National Grid Electricity System Operator – NGESO – expects these runs of non-coal power to become the new normal as UK renewables source infrastructure increases. Julian Leslie believes that by 2025 we will be able to fully operate Great Britain’s electricity system with zero carbon. This requires a significant boost to renewable energy production. With seven of the UK’s eight nuclear power plants stopping energy production in the next 11 years and only one new plant due into operation, emissions could begin to rise without sufficient renewable energy ready to fill the gap.

This is a business operation as much as an engineering challenge. Investment is essential. Third-party services must be identified and secured. If your company is in the offshore wind industry, you might be interested in the Global Offshore Wind conference in Manchester on the 19th-20th June. You can find out more about that at

Energy efficient appliances

The bigger the fridge the more power it uses

Energy is precious and usually expensive. You don’t want to waste the energy you pay for. There are all sorts of ways to save energy in the home and we’ll be talking about as many as we can in coming episodes, but one that we all face from time to time is replacing an energy-hungry appliance such as a fridge or a washing machine.

According to the UK spends almost £3.5bn on electricity each year just to keep our clothes clean, wash our dishes and freeze our food. The worst offenders include electric immersion heaters, fires and showers, the dishwasher and it won’t surprise you to hear, the tumble drier.

These items and the other household items we rely on such as boilers and freezers take a great deal of water and energy to produce in the first place, so consider carefully just what it is you’re wanting to achieve – is it lower household bills through running more energy efficient appliances, or reducing your overall consumption of raw materials by using an appliance until it’s beyond repair? The energy efficiency of household items has improved in leaps and bounds in the last few years so there are great energy savings to be made. If the time has finally come to replace an item, what do you look out for, and who do you trust?


UK renewables
The discontinued Ecoflap letter box draught excluder

The Energy Saving Trust is a good starting point. It’s a source of objective information but it also endorses products – including our now-discontinued letter box draught excluder the Ecoflap. A quick glance at its website provides food for thought including the excellent advice to consider the size of appliance you need. One person on their own is unlikely to need to same capacity fridge or washing machine as a family of six. Energy rating is dependent on size: two fridges with the same rating but that are different sizes will have different running costs. It also includes information on how to run your household goods efficiently plus how to dispose of the old ones.

Good habits

Interestingly it seems we pay far more attention to the energy rating of the ‘workhorse’ items such as white goods when we’re looking to buy than we do to consumer electronics such as a TV. We then tend to leave these items on stand-by, which racks up power usage and therefore bills. Whether it’s the financial hit, the environmental impact or both that bother you, it’s worth getting into a few good habits. Some gadgets don’t like being switched on and off too much, it can cause its own problems, but unless your life is run by the microwave clock it’s not going to be much hassle to turn the microwave off at the wall when you’re not using it. Power down your PC overnight or when you’re out for the day, same for the TV. You could save around £30 a year, depending on your personal set-up.

Small energy suppliers going bust

At least eight small energy suppliers have gone bust in the last couple of years, with One Select the latest casualty. What’s behind this slew of failures, and what happens when your energy supplier ceases trading?


Answering that last question first, Ofgem steps in when a supplier goes under. Ofgem will ensure your energy supply continues, that any credit balance is protected, and will allocate you a new supplier. Ofgem’s advise is to “sit tight and don’t switch supplier”.

Turbulent sector

The energy sector has been turbulent over the last couple of years. This is partly due to tightened regulation and a government-enforced price cap on some tariffs. They are designed to remove overcharging and profiteering. Ofgem expects this energy cap to save customers between £75-120, depending on their plan. The price cap level will be updated in April and October every year to reflect the latest estimated costs of supplying electricity and gas, including wholesale energy costs.

New suppliers

Ofgem has tightened its rules for new energy suppliers entering the market. They must prove adequate financial resources but also crucially that they can meet customer service obligations. Consumers have been angry over rising bills and poor customer service. Perhaps this is why April this year saw a record number of customers switch to a new supplier. The overwhelming majority switched away from the big six to small and medium companies despite the collapses. This process seems not to be smooth however. Complaints about the switching process just overtake comnplaints about other aspects of customer service. Ofgem is clearly taking customer service capabilities seriously. It banned one provider from taking on new customers until it had sorted out its problems.

In the event of a problem the Energy Ombudsman can step in to mediate and to date has solved nearly 100,000 cases. The most common complaint is misbilling. Smart meters should help with this – something we’ll be talking about soon – but roll-out is far from complete and mistakes can still happen.

Lack of information is a common cry with bills, with some customers experiencing changes to their Direct Debit without the requisite notice period, or bills simply not appearing. Of course prices go up too, but suppliers should give customers 30 days notice of any rises. On a fixed tariff the price can increase only if the government increases VAT. The notice period for a fixed tariff is 42-49 days, giving customers time to find a new deal without exit fees. If a customer finds themselves struggling to pay their bill Ofgem’s advice is to talk to the supplier as quickly as possible to work out an affordable plan. There is plenty of information available online about energy supply, your rights and what to do if there’s an issue.

Home draughtproofing

If we’re lucky enough to have decent summer weather in the UK, it’s easy to forget about draughtproofing. It doesn’t feel important when the weather’s warm and no-one’s noticing the draughts creeping under doors and through poorly-fitting windows. However this is to miss an opportunity to make improvements, literally fixing the roof while the sun shines. These steps can be large, such as fitting a new boiler or having other central heating improvements made while you’re unlikely to be needing the heating on, or small, depending on your set-up and your budget.

uk renewables
Chimney Sheep

We want to feature energy saving household products on this pod, and we’re starting with the Chimney Sheep. This is the classic bright idea – simple but effective and you wonder why you didn’t think it up yourself. Essentially the Chimney Sheep is a chimney blocker made of 100% Herdwick wool. It’s inserted into the chimney (when the fire isn’t being used) to prevent draughts, birds nests and so on whistling down the chimney.

Chimneys draw air through them all the time, whether the fire is lit or not, creating draughts. Fitting a Chimney Sheep interrupts this air flow but allows a chimney to breathe. Like our products, it helps to keep warm air in during the winter, and cooled air in during the summer, and offers a bespoke option. The Chimney Sheep starts from £16. The Chimney Sheep includes some impressive statistics on carbon saving and bill reduction, so visit them at to find out more about this innovative product and buy one to tuck up the chimney over the summer months.

What are we up to? We’re a family firm designing and manufacturing draughtproofing products for the home. Right now we’re developing a new piece of kit for shaping trunking, and relocating some of our operations from one base to another. We’re also designing the manufacturing of the Letterplate Eco, the new external letterbox draught excluder that will replace the Ecoflap. When he heard about the new podcast our lead designer, Richard, leapt in with a tip of the day, so here it is.

Richard’s tip of the week

Fit a small ledge above your thermostat to change the movement of air around it. This will provide a more accurate temperature reading. Warm air rises then cools as it comes into contact with walls and the ceiling. This cooled air, which is cooler than the air in the middle of the room, falls back down the walls and on to the thermostat. It will give the thermostat the impression that the room is colder than it really is. This can cause your heating to come on when you don’t want it to, using excess energy and increasing your bills. There are plenty more of Richard’s tips where that came from, so we will aim to bring you one every week!

Thank you for listening. Search for Ecoflap on Twitter and Instagram to keep up with us until next time, when we’ll be looking at EnerPHit and passivhaus, smart meters and community projects.

“Werq” Kevin MacLeod (
Licensed under Creative Commons: By Attribution 3.0 License