This article describes how, even in winter, my house is warm throughout, my Octopus account is £400 in credit, and my last bill, of £5, was six months ago.  My long journey has been one of experimentation, misplaced optimism, sweat and toil, disappointment, and finally, satisfaction and economical warmth. The purpose of describing my efforts is to spare you the first four of these, so you can enjoy the fifth without undue cost or delay.

The rocky path to my enlightenment started in an attic bedsit in Headingley, which offered a similar level of comfort to a bus shelter, but at greater cost. The landlord arrived one day clutching several rolls of expanded polystyrene wallpaper about 3 mm thick, and offered me one week’s rent relief if I would apply this to the ceiling of my accommodation and the room next door. It felt wonderfully warm to handle, and I enthusiastically accepted his suggestion. I completed the work during the following four evenings, eagerly anticipating some relief from the relentless chill of a Yorkshire January. And so came the first disappointment: There was no obvious improvement.

Lesson one: first impressions can be misleading. Three mm of any readily available insulation material will not do much, even if it is warm to the touch.

In 1982, I bought a stone terraced house in Otley, and having of necessity removed the lethal leaking pipework and the ineffective gas fires, “enjoyed” an open fire, an ancient Yorkshire range, a solid fuel cooking stove, and a woodburner over a number of years, while slowly developing an understanding of anthropogenic global warming and the health implications of breathing toxic combustion products. I spent a lot of money on fuel and many hours shovelling coal, cutting wood, disposing of ash, and cleaning dust from all over the house, which was still only tolerably warm in the immediate vicinity of these appliances or the radiators which some of them sometimes served.

Lesson two: there is more to being warm at home than simply burning fuel, comforting though that can often be.

Charming but inefficient and polluting.
Great for cold toes; less so for lungs.

I found printed articles about insulation (there was no Internet at that time), and set about insulating the attic ceiling with 150 mm (6 inches) of expanded polystyrene, convinced that blissful warmth would now be mine to enjoy. And so it was, while the stove in the kitchen was supplying warm water to the radiator in that room. The comfort was, however, fleeting and the familiar chill would set in within minutes of the fire downstairs going out.

Lesson three: even fairly large amounts of poorly chosen insulation material can deliver disappointing results.

At the same time as insulating the attic, I removed the decrepit decaying dormer and replaced it with a huge double glazed tilting roof window.  

Natural light is free. Heat lost through large windows is not.

Sunlight flooded into the room, and the view of the Chevin was wonderful.    Less wonderful was the condensation which collected on the glass during the cold weather of autumn and winter, and ran down to stain the wall below, and make the carpet go mouldy. Now there’s a smaller triple glazed Velux.

Lesson four: although the light is welcome, large areas of glass are a magnet for condensation, and can lose a lot of heat which is expensive to replace.

I love the solid stone walls of my home, and sometimes think about the hands which shaped the blocks and laid them carefully in position. The feeling of security within them which I experienced on my first day in the house has endured 40 years, but my tolerance of their cold and damp condition during the winter months did not last nearly that long, for their thermal properties as built leave very much to be desired.  

A triple glazed window & insulation.
A nice place to read a good book.

Lesson five: no matter how reassuringly protective thick stone walls look, without insulation, heat escapes through them very quickly, resulting in discomfort, condensation, ill-health, expense and needless CO2 production.

While dealing with an electrical fault one day, I lifted some floorboards adjacent to the back wall of the house, and was dismayed to find cold air streaming in around one of the joists where it was set into the wall. If there had ever been any mortar, it was long gone.  

Out of sight, out of mind, and wasteful.

A wider examination revealed that this was also true of the adjacent timbers.   All this added up to an icy gale blowing into the spaces between the beams, above the kitchen ceiling and below the bathroom and bedroom floors, which blew out of the gaps between the planks and underneath the skirting boards. I might as well have been living in a tent. It was no wonder that my energy saving efforts thus far had resulted in such little improvement.

Lesson six: Jack Frost enters our houses stealthily by unseen routes to steal our hard-earned money and make us cold and miserable.

The original sash windows had previously been replaced by wooden ones from a well-known firm, which were obviously not going to last much longer. They were, furthermore, only single glazed, and condensation was a regular occurrence, especially in winter. After I had replaced a couple of them with double glazed PVC windows, I became familiar with the thermal calculations needed to work out that double glazing would not be sufficient to achieve the economical comfort I wanted, and was pleasantly surprised to discover that triple glazed windows did not cost so much more.

Lesson seven: triple glazing reduces heat loss through windows, and makes your house more comfortable and quieter. Its relatively small extra cost is recovered in a few years, during which time you’re more comfortable.

I discovered PIR insulation material (polyisocyanurate, if you must know) at the local builders’ yard, which would allow me to insulate the walls and roof to a suitable standard without an unacceptable reduction of my living space.  Inch for inch, it is nearly twice as effective as anything else you can afford.   A lifelong interest in weather had given me a good understanding of the relationship between air temperature and humidity, and I put this to good use in my subsequent insulation work, to be sure that wooden components of my house would not be adversely affected by moisture from within. When I applied these new measures to the guest bedroom, it soon became apparent that the radiator I had laboriously fitted not so long before was superfluous.

Lesson eight: The combination of triple glazing carefully fitted, 150 mm of PIR insulation (or equivalent) carefully applied, and 100% airtightness renders conventional heating systems unnecessary in many instances.

Following this breakthrough, the double glazed windows found a new life in a house down the street where they fitted perfectly, and all the windows in the house with the exception of one Velux are now triple glazed.  

All rooms were similarly treated.

Over the next few years, all the remaining rooms in the house received the same treatment, which had two effects:

1. The house became wonderfully warm all winter.

2. The air quality became terrible.

I had always believed that ventilation systems were something fancy, and only to be found in the homes of the rich and famous, but I was now in the process of finding out that they are an essential part of a pleasant and healthy domestic environment. There are British and European standards which demand appropriate rates of air exchange in houses according to their size, number of occupants, and type and number of rooms.

Apart from occasional extractor fans, British houses are naturally ventilated, which is a polite way of saying they are about as airtight as a kitchen colander. In windless weather they are stuffy, and in a gale you might as well be sitting in the garden. In my warm, airtight house, this was no longer the case, but ventilation was now obviously needed. I fitted a system with heat recovery, so that cold fresh air coming into the house is heated by the warm stale air being extracted. Without this feature, considerable power and money would be expended heating the incoming air to a comfortable temperature, while the warmth contained in the extracted air would be lost.  

With the benefit of hindsight, life would have been easier if I had anticipated this requirement from the outset and planned in a ventilation system from square one. Threading 5” diameter pipework between the existing features of the house was sometimes challenging. Don’t say I didn’t warn you…

Lesson nine: MVHR (Mechanical Ventilation with Heat Recovery), far from being an expensive luxury, is essential for economical comfort and health, and should be planned in from an early stage of any renovation. Why it is not included in the proposed 2025 Future Homes Standard is perplexing.

Kitchen and bathroom odours and humidity are gone in minutes, towels are quickly dry and hygienic after use, and washing can be dried overnight without a hint of condensation. The energy consumed by the system is far less than that recovered by its heat exchanger. Yes, the windows may still be opened…

At this point, I got rid of the last wood stove with its mess and pollution, and installed a small heat pump to provide the little heat the house still needs using electricity. As this is a fairly compact house, the position of the inside unit at the bottom of the stairs allows my entire home to be adequately heated by convection up the staircase, and by the air circulated by the ventilation system. The man with the horse and cart has taken the remaining radiators. The house is tidier without them, and needs less maintenance.  

1 kW of electricity consumed, 3 kW of heating (or cooling) produced.

An array of 16 solar panels on the roof generates more electricity than my home needs in a year, but not always when it is needed. A small storage battery handles daily discrepancies between availability and demand, and the National Grid, advantageously connected via a smart meter and a flexible tariff, deals with seasonal shortfalls and excesses.

More power is exported in summer than imported in winter.

Lesson ten: smart systems, solar panels, batteries and heat pumps all have their part to play, but can be an expensive distraction if your house leaks energy like a sieve. It makes little sense to invest in these before the efficiency of the fabric of the house has been improved to a high standard.

Anyone with determination, an enquiring mind and a good pair of hands can retrofit a house to be comfortable and economical, as time and funds allow. Rigorous application of the principles of Passive House design, as identified by Dr Wolfgang Feist, is one established route to success, and access to an architect who can apply PHPP, the Passive House Planning Package, will bring a high degree of certainty to the outcome, and the possibility of valuable EnerPHit certification upon completion. All those working on the project will need to be fully conversant with the techniques, materials and components involved, and be suitably committed, trained and supervised.  

Sadly, most British building companies can’t offer the necessary skills or attention to detail, although there are a few that do.

Conclusion: There is no need for houses to have the huge carbon footprint they currently do, or to cause hardship when fuel is dear. Economical, healthy, comfortable living and its benefits could now be enjoyed by all, without any new materials or technologies having to be developed. Elsewhere in Europe, new houses are efficient, and properly funded long term schemes are in place to enable older properties to be improved. Why England is fast becoming unique in its inability to provide decent, affordable houses for its citizens, and why its workforce is so poorly trained as to be more a hazard than a help when building a low-energy house, are questions to ask of the party which has been in government quite long enough to put these things to rights.