insulation’s what we need….!

…in which David and Zaria come to terms with internal wall insulation.

So, thanks to Lewisham’s archives we discovered that our house was built in 1900. Originally it had a tiny kitchen and an outdoor toilet and housed a family of six: two parents and four adult, working offspring.  The most fascinating thing, to me, was the social profile of those first occupants: they worked in shops, apparently as specialised shop assistants; haberdashers and one ironmongers. This house was built for the worker-ants of the city. Nowadays we feel like the lucky privileged to live in this charming house, (although perhaps our status as slightly more fortunate worker-ants could be argued: we’re educationalists). I feel incredibly lucky to live here myself, and enjoy its Victorian charm, but who knows the future occupants of this house, or their fortunes indeed of the city. I mention this because a large part of my concern around environmental degradation and climate change is social: how badly it affects us is closely linked to our access to resource and our social position. For example, remember how terribly badly the poorer citizens of New Orleans suffered after hurricane Katrina, and, closer to home, how apparently homes in areas of lower pollution in London are becoming more desirable, with, one presumes, a consequent price-tag. Neighbours, be thankful we live up a nice hill with (ahem) lots of trees on it!

EPCMuch as we love our house, our Energy Performance Certificate,  makes us cringe, and we’re doing our best to improve it. The place is a heat colander, costs a fortune to heat and belches CO2 into the atmosphere. In a previous post I attached a graphic of a useful outline guide to making our home more environmental. The first step is to make the building more energy efficient, stopping up drafts and insulating so that less heat escapes through the walls.

The first step was to find out where the heat was actually escaping from. Apart from the chimneys, which I addressed in the last post, it seems it was everywhere. But we started with the walls. They needed to be insulated.

Those with homes built approximately after 1920 may have cavity walls, which can be filled to great effect and for very little disruption or cost. For those in Victorian properties with solid brick walls, it’s either inside or outside. For us, both were a problem. My friend Paulina, who lives nearby (see left) had opted for external, which works fine for her but it does appear to stick out a bit from the other terraces. You can see why external isulation isn’t allowed in conservation areas. Apparently you can have different colours, though. More on Paulina’s opinions in a later post on what it actually feels like to live in an internally insulated home.

We went for internal, mainly because we have a locally famous wisteria plant clinging to two of our walls, which we judge to be possibly almost as old as the house. We love it, and were indignant at suggestions that we might cut it down to facilitate external wall insulation.

There were two standout house_plantissues involved in internal insulation: firstly, the insulation would mean the removal of all cornices, features and moulding on the walls, which to us are important features of the house’s history. Secondly, the insulation in total is about 8cm thick, which means losing all that space off rooms, some on two walls, and so the furniture and shelving possibly not fitting. These were both barriers, so we had to put our thinking caps on.

We only had original mouldings and cornices on the ground floor, so we agreed to go for the first floor only, which included the bedrooms. Internal insulation only goes on the inside of external walls. Interestingly, I also found this graphic taken with an infrared camera which shows the relative warmth and cool of of books on a bookshelf against a cold wall.

thanks to for the image

This is great, because we have loads of books and ironically many of those books are about Sustainability and Environment and how we’re all going to hell in a handcart, etc.

We also wondered about the change in shape of rooms, and walls and atmosphere and windows. Around the time we were thinking about it we went to St Fagans, the Welsh history museum, where I saw this window, and wondered about what our bedroom might look like with 8cm of insulation on it.



I’m going to need to dedicate a new post to the actual process and effects of internal wall insulation. Below, however, an image of how it actually works, which explains the technical details better than I could.

Next…an adventure in which internal wall insulation becomes real..


Chim chim cherooo…

…in which Zaria and David attempt to stop the flow of air out of their chimneys.

When thinking about chimneys I sometimes smile at the idea that Father Christmas, traditionally assumed to be a corpulent gent, is supposed to come down chimneys while until not so long ago only young children were thought little enough to get up them to clean them. I wonder if this contradiction every occurred to any Victorian chimney-beneficiaries when they may have watched their underclass contemporaries shin up to clean them (presumably whistling cheerful Mary Poppins ditties).

The open fireplaces was one detail which drew me to our Victorian house. We have two functioning chimneys on our ground floor, and here’s the smaller one, most used by us of a chilly evening. There’s nothing quite like it for cosiness….


I grew up in one and I have almost embarrassingly twee memories of the thrill of toasting crumpets, etc.As an adult homeowner, however, I’m troubled by how much warmth is actually lost up chimneys when they are not being used, and indeed they are in effect simply a large hole leading from warm rooms into the cold outside. They are one way in which Victorian houses bleed heat into the atmosphere. Futhermore, I’ve discovered that while burning they change the air dynamic in your house, by consuming oxygen in already-heated air, thus pulling warm air out, so making the rest of the room slightly cooler as the fire in the fireplace radiates its local heat. One expert organisation has claimed that 40 cubic metres of air are sucked out of a room every hour that the fire is lit. Altogether, an open fire is not a sustainable thing to have in your home but as ours are focal areas of the rooms they grace their loss would really change the look and feel of those rooms, we’re prepared to keep them and try and make them as green as possible.

So, stopping up a gaping hole in your house should be one of the more immediate tasks of making your home more energy-efficient, but it turns out not to be so easy. Some people simply stuff newspaper up their chimneys but we wanted to be a bit more thorough than this. Our first attempt involved an inflatable balloon called a Chimsoc. The theory was that you stuff it up the chimney uninflected, then blow up a tube to inflate it in its final position about 50cm above the opening into your fireplace. It thus takes the shape of your chimney (they vary quite a bit) and traps a balloon of warm air quite low in your chimney, separating it from the cold air above. The massive design flaw in this, however, is that of course as soon as the warm balloon cools a little, say, when the heating of the house is turned off at night, it shrinks enough to slide down the chimney, losing its snug fit and leaving  gaps for the heat to escape through when the room warms again. Finally it simply flops down into the cold fireplace, epic fail. See below.







David, my lovely partner, looking unimpressed. We regretted the £35 we’d spent on it.

Second attempt was a bit more successful: the Chimella. We bought one after seeing a demonstration at Ecobuild 2015 [youtube link]. As it says on the packet…..


The Chimella, while sounding like something indeed out of Mary Poppins, is in fact a kind of umbrella. You put it up the chimney closed, then open it like a normal umbrella with a button, and then wiggle it to position it inside the chimney. The youtube presentation is much clearer, and see below some more pictures of my glamourous assistant demonstrating:


The chimella closed







And open, achieved through pressing a button on the stem. Note, David looks a bit happier about this…











David demonstrates the length of the chimella stem: it’s extendable for very long chimneys! Suspect he’s contemplating an out-of-character Mary Poppins singalong moment…

















Putting the Chimella up was a bit more of a faff than we’d thought: it involved David putting the upper part of his body right up the chimney, like a latter-day chimney sweep. SAMSUNG CAMERA PICTURES






So far, however, we’re happy with this: it seems to have done the trick, although not having turned the heating on yet, we’re still withholding judgement.

The last method of stopping the chimney has a fabulous strap-line: ‘there’s a sheep up your chimney’. It’s a sheep’s wool pad, on a long stick, which you simply ram up the chimney. See below.
























This is all very amusing, but actually sits on the very fault line of the problem of retro-fitting. How do you take a house designed for another era and equip it for a future in which energy will be possibly expensive and limited, and limited lifestyles will be the norm?







An alternative idea is that in the future all energy generated will be clean and free, so possibly losing heat up the chimney will not be such a problem. However, the government is threatening to remove the subsidies that support and stimulate the fledgling renewable energy industry, making this now a sadly more distant prospect.

Next, to the more demanding prospect of insulating and also continuing the draft-proofing the brick colander. We’ve survived a winter with a new baby, and her second winter is coming….

Midwinter: what’s ‘chopping’ got to do with it?

The Chop Cloc: a new way of thinking of domestic warmth

Zaria_Sequoia3As the spring warms, we gratefully lower our heating and allow the sun to stream through the open doors. I find that my skin almost doesn’t remember the touch of warm sun, and of course our little daughter, born in the middle of frozen winter, is experiencing the first proper sun of her little life. She’s even got a slight suntan (very bad parenting..tut tut).

Just before her birth a visitor loomed out of the winter mist on Blythe Hill: Garry Stewart from Scotland bearing a Chop Cloc. This is a new and ingenious invention designed to facilitate the practice of ‘chopping’ which means cutting out your boiler for short periods, allowing the heating to ‘coast’ in your home, without dropping the temperature noticeably. It’s a way of saving significantly on heating costs and carbon emissions while maintaining a healthy temperature. It’s called a ‘clock’ because it kind of looks like a clock, and it works based on time, see the images here:


You can set it to cut out (‘chop’) from 15 to 45 minutes in the hour, by simply twiddling the dial. It has a ‘no chop’ setting too, if you just want things full on. Apparently, if you find your comfort zone you shouldn’t need to change it that often.

It has to be wired into your boiler, see the image here of Garry doing the doings.















Garry_wiringupThere are several useful things about the Chop Cloc. Firstly, and most relevantly to us, it is a ‘retrofit’ device, designed to be wired into existing boiler systems to make them more efficient. It’s claimed to save up to 30% on heating bills, and is designed to address both carbon emissions and fuel poverty. Apparently fuel poverty is much more widespread than you’d think, with average yearly fuel bills reaching nearly £600 this year, a shocking rise of 63% from 2008. This, combined with the economic fallout from the banking crisis and subsequent recession, means that more of us are challenged by fuel bills than previously.

Heating of course became priority for us when having a new baby in the depths of winter, so Garry’s visit was most welcome (in retrospect I think of him as one of the three wise kings come a bit early and bearing a very useful gift). In our house we had discussed keeping the heating on at night, which for us environmentalists felt like buying a four-wheeled drive and making friends with Jeremy Clarkson all of a sudden (ok, we probably take ourselves too seriously). The ‘Chop Cloc’, however, changed this and made us feel better as well as saving us quite a bit of cash. My devoted partner turned it to ‘15’ each evening, which means that the boiler cut out for 15 minutes in each hour, thus saving us money and energy and making night feeds sooooo much more comfortable. Anyone who’s had a new baby knows how those early months are: bleary-eyed, feeding at lonely freezing hours of the night, and feeling as though you are the only one in the world awake.

The concept of the Chop Cloc relies on the fact that actually most heating systems overwork, and while they are efficient at maximum power at the coldest times of the year, they waste energy most of the time in our temperate climate. Even if the boiler itself is efficient at converting gas to heat, using that heat well, to keep us comfortable, is about delivering it sufficiently without oversupplying it when it’s not really needed. Garry explained that he is suspicious of thermostats, mainly because they don’t really reflect human comfort: apparently we don’t notice slow changes in temperature up to 2°C, it’s only more extreme changes that bother us. As long as we stay within our ‘comfort zone’ we are fine.

Thermostats are usually installed in passages or landings, which are areas of the home where people don’t spend a lot of time, so they are generally a bit colder, thus making our boilers hike it up unnecessarily. Crucially, however, thermostats mainly measure air temperature, which is only a partial measure of the whole temperature and comfort of the house. Radiant heat from walls, floors, ceilings, and furniture plays a big part in maintaining a comfortable temperature inside a building, while apparently the thermostat is a blunt instrument for regulating this. Plus, no-one understands them (I admit, I don’t understand mine, do you?). The chop clock means that you can save a reasonable amount of energy and money by simply cutting out your boiler and avoiding the overproduction that I’ve detailed above. And it’s easier to understand than a thermostat.

The Chop Cloc is seen as a great invention within the field and is moving onto wider markets. It’s been used a lot in social housing in England and Scotland, and to date it has won the Rushlight Energy Environmental Award, was Highly Commended in the Business Green Awards and been shortlisted for the Sustainability Leaders and the Energy Efficiency & Renewables Awards.

If you want to know more about Chopping and how it works, go to their website here: If you want to buy one, they’re about £70, you can buy them online here: and you need a ‘competent person’ to install it (although apparently it’s not very difficult).

In strategizing to make our home greener we have been greatly guided by the hierarchy of retrofit action, see the image: firstly you try to use less energy, by switching things off, etc. Next, you need to try and use technology to try and make the very best use of the energy that you do use, such as insulating, draft-proofing and ‘Chopping’. The pinnacle of the triangle, the highest and hardest achievement, is working towards generating renewable energy (although this image puts the final achievement at the bottom of the image, suggesting perhaps the cut in energy usage?).



We try to buy A++ appliances wherever possible, and we’ve insulated most curtains. The windows still rattle, however, being Victorian sash windows, and the walls are paper thin and strangely seem to emit cold rather than radiant heat. People notice the slight drop in temperature when coming in (so it must be more than 2°C, scary). This makes it great in a heat wave, but terrible in a cold winter.

For now, I’m just massively enjoying the new warmth of the sun, not having to swaddle my little daughter in layers of clothes to keep her fragile little body warm, and sitting in the park occasionally without my shoes on…simple pleasures.

Committed environmentalists but love Victorian homes? Tough conflict!

homexchange_picI consider myself a really committed environmentalist, and I’ve worked for environmental charities, mainly in education, in an attempt to ‘make a difference’, such as I can. Part of my learning about the environment, however, has led me to look at my own home and its impact on the environment. I discovered that nearly 30% of the UK’s CO2 emissions are from housing, and 27% of our national housing is old (considered to be built before 1919). This makes addressing the emissions of our own housing one of the best things we can do as individuals to mitigate climate change.

When we bought our beautiful house in February 2013 we were in love with its age, the house_wisteriaEnglishness of it: its quirky corners, the unexpected staircase, understated stained glass, original fireplaces and moldings. There are even the original stone floors. This should have all pulled in a very pretty penny indeed, and the fact that it was actually within our price bracket seemed like a miracle. We didn’t actually ask ourselves why, at the time. The EPC was given as 51, an embarrassing orange E, with a potential of 83, a cheerful mid-green B, which us eco-heads could be proud of. We told each other cheerfully that potential was everything (having seen grand designs, etc.). It’s the gap between the actual and the potential that we’re steeling ourselves to address now.

Part of my attraction to the house is that it speaks to my middle-class identity: like many middle-class Londoners I feel a deep affinity with London yellow brick and Victorian and Edwardian cultural objects (if not necessarily the values of those ages). In many ways, the eighteenth and nineteenth centuries were where the British bourgeois culture was forged, explaining perhaps the widespread attachment to ‘the look’. Which is lucky, as the greater part of London is swimming in it.

window_image In terms of retrofitting, however, it’s a nightmare. These Victorian houses are no better than ‘brick tents’ (as George Monbiot, I believe, once described them). They are also full of ‘period features’, which, I’ve discovered, I’d rather freeze than part with.

The weekend we moved in was the first in March of 2013, when a ferociously cold snap gripped London. We turned on the central heating and nothing much happened. There is no double-glazing, the walls are a mere two bricks thick and the windows rattle in their ill-fitting sashes. The first few days we slept in our clothes and awoke to see our breath in clouds. We couldn’t believe it.

Since then we’ve substituted a horrible old water tank in the attic with a new condensing boiler, and we’ve had an attic extension which includes the now requisite 27cm of insulation in the roof, and built-in wall insulation. I’ve also lined most of the curtains, which makes a big difference on winter nights. We’ve also covered a few strategic points with both Perspex secondary glazing and the cling-fim-like stuff which you need to hairdryer on. That works patchily and can sometimes billow and crackle eerily in the draft. Really, what the place needs is an eco-make-over.

So, after some negotiation, we are to have internal wall insulation in the bedrooms upstairs. It has been a journey to arrive at this point, and it’s not over yet. Watch this space for more.

Paul’s introduction

Hi. To introduce our home as the starting point, our family of three live in an extended 1930s semi in Crofton Park. It is one of many very similar houses in between Crofton Park and Ladywell so hopefully it will serve as a demonstration of what can be done to improve these and make them more comfortable.

front intro

In winter it seems difficult to get our home to a comfortable temperature, and the heat will disappear as soon as the heating is switched off. It can lead to battles over the thermostat, so the result of any improvements should be a combination of reducing our bills and making our home more comfortable.

The first part of the work was to have an assessment of the house, resulting in an Energy Performance Certificate (the sort that is required now whenever you sell a home). This shows the potential for any improvements and exactly what could be considered.

Our home received a ‘D’ rating, with a EPCpotential to scrape into a ‘B’. Looking through the property section of the local papers, ‘D’ seems fairly typical of 1930s properties, with older properties not always faring as well.

Unfortunately it looks as though the work isn’t going to be completed until the winter is over so it will be a while before any improvement is really going to be felt, but one of the companies involved plan to do a more detailed Energy Performance Certificate assessment and repeat it after all the work to show the difference.

Another measurement they’ve done is an air tightness test. This involves sealing all Air testdeliberate ventilation, such as air bricks, and then pumping in air from outside and measuring how quickly it leaks out of the house. This measures how frequently the air inside is exchanged through leaks in the building, and therefore how quickly the air heated by our central heating is replaced by cold air that needs heating again. I’m waiting to see the results from this, although they said it was fairly typical for the age of our house. Again, they plan to come back after the work to repeat the test to show how much it has been improved.

I am a bit of a data geek so I’ve managed to get hold of various temperature loggers, and I have monthly gas and electricity readings going back quite a way. Hopefully this will provide some colourful graphs to go alongside subjective impressions of how much more comfortable it feels. I’ll write in more detail later about all the data that I’m collecting.