A Short History



‘Those who do not know history are destined to repeat it.’

Edmund Burke.



It seems that the term ‘North Sea timewarp’ was first used in the 1970s by Dr. Bob Lowe, now Prof. Lowe and Deputy Director of the UCL Energy Institute. Visiting Sweden or Denmark, this phrase did come to mind.

There is also a North Atlantic timewarp. What people think of as brand new can sometimes be more a case of ‘goes around, comes around’.

The waste of resources from this so-called ‘forgetting curve’ can be very high if people ignore the previous knowledge base and forge ahead in ignorance of what has gone 30-40 years before. It is often prudent to assess existing knowledge and ‘best practice’ before commissioning a green building.


Well-Insulated Cavity Walls

Danish Cavity Wall 040914This cavity wall may look moderately well-insulated to UK readers. Presumably the picture was taken in the last ten years, since the improvements to Part L of the Building Regulations?

Not at all. It was taken in Denmark in summer 1977. The 1977 Danish Building Regulations required 75 mm or more of mineral fibre batts in new masonry walls.


Danish Cavity Wall 1977.


Picture © Prof. R. J. Lowe.

Solar Heating and Seasonal Storage

ZEH 040914



Lyngby Zero-Energy House


Picture © Torben Esbensen.


The year was 1975. The above well-insulated, draughtproof house was built at the Technical University of Denmark. The vertical solar collectors fed a seasonal underground heat store, the aim being to store the sun’s energy from summer to winter to heat the house.

The solar collectors and heat store had technical problems but the rest of the building worked well. It inspired much later European work on energy-efficient buildings.

Larger Solar Heating Systems

Built in 1978 at Studsvik, Sweden, the office block below was heated by the ground-mounted solar collectors. Positioned on top of an underground, insulated, conical seasonal heat store, these collectors rotated once a day from spring to autumn to track the Swedish summer sun. Hot water was stored to heat the office from November to late March.

The experience at Studsvik onwards showed that solar heating was very successful and economic if it was pursued on a large scale. These projects were the precursor of today’s Danish solar heating schemes, which are connected to its district heating systems and heat a small town rather than a single house.


Studsvik 1978



Studsvik Solar Heating System, Sweden.


Picture © Prof. R. J. Lowe.


Retrofit External Solid Wall Insulation

Sweden external insulation 1979Seen in June 1979, this tower block in Sweden was being externally-insulated with slabs of 100 mm mineral fibre and clad by a new brickwork skin. In the process, the appearance was improved and the wall heat loss was reduced about four-fold.


Retrofit External Insulation, Swedish-Style, 1979.


Picture © Prof. R. J. Lowe.


Walls with 200 mm External Insulation

Schiedam 1982In 1982, the town of Schiedam in the Netherlands constructed an estate of 184 ‘Minimum Energy’ dwellings for rent. They had 200 mm of EPS foam wall insulation, double glazing with insulating shutters, they were very draughtproof and mechanical ventilation and heat recovery was fitted. The homes consumed 80% less natural gas than normal new construction. The extra cost was fairly soon repaid in fuel savings.


Minimum Energy Houses, Schiedam, Netherlands, 1982.


Picture © Dr. C. Ziydeveldt.


Insulated Party Walls

As many UK designers today are aware, separating walls have to be designed to provide satisfactory acoustic and satisfactory thermal insulation. This usually means filling any wall cavity which is formed between the attached buildings with suitable thermal insulation material.

Fair enough, but surely this awareness is quite new? Not really. Spot the acoustic insulation in these party walls in Lambohov, Linköping, Sweden. This row of precast concrete-walled houses was under construction in June 1979.





New row houses, Lambohov, 1979.


Picture © EAA.



Superinsulated Houses

In 1976-77, Saskatchewan Research Council built an experimental house with extremely high insulation and draughtproofing standards. Even in central Canada, its space heating bill was under $100/year. This early work in the USA and Canada would eventually lead to the development of the Passivhaus, MINERGIE and MINERGIE-P Standards.

The Saskatchewan Conservation House predated low-e window glass by three years. So it ‘only’ had triple-glazed windows with insulated external shutters. Its roof-mounted active solar system was expensive and was later removed. But its energy efficiency measures were a great success.


SCH 030914



The Saskatchewan Conservation House, Regina, Canada, 1976.


Picture © Dr. Rob Dumont.


Related Work in Germany

image9Independently, spurred on by the 1973 oil crisis and high world energy prices, Phillips NV built an experimental house in Aachen, Germany. This project too had high insulation levels, draughtproof construction and well-insulated windows. It also had an active solar system on the roof. This contributed towards the building’s space and water heating needs.

The Philips Experimental House, Aachen, Germany, 1974.

Picture © Philips NV. 


Pioneering individuals followed suit. Eugene Leger, a Building Control officer, built the modest house below – a bungalow and basement – in East Pepperell, Massachusetts, USA in 1979. Its gas bill for heating was $38/year.





The Leger House, Massachusetts, USA, 1979.

Picture © Eugene Leger.



‘Net Zero Energy’ Buildings

image11In 1982-83, the Rocky Mountain Institute constructed a very energy-efficient headquarters building in Colorado. It aimed at close to ‘net zero energy’, producing as much or more energy than it consumed. By 1992, with solar PV added on the roof, this became a reality.


Rocky Mountain Institute, Colorado, USA, 1983

Picture © RMI.

Superinsulated Retrofits

The techniques of superinsulation soon spread to existing buildings. Below is a picture of a ‘chainsaw retrofit’ undertaken in Saskatoon, Saskatchewan, Canada in 1982. It reduced the bungalow’s space heating bill by over 85%.

After adding an air barrier, the 1968 house was externally insulated on its roof and walls. Air leakage was reduced from an already low 3.0 air changes per hour at 50 Pascals (ac/h @ 50 Pa) to a very low 0.3 ac/h @ 50 Pa. Heat recovery ventilation was fitted and a third pane of glass was added to the existing windows.

The title refers to the use of a chainsaw to remove the existing roof overhang before adding an air barrier and extra insulation. At a minimum, several hundred such projects were completed in the northern USA and Canada from the late 1970s to the late 1980s. The accumulated know-how is both extensive and highly dispersed.

The experts involved in North American projects 30 years ago doubt that the cost of ‘superinsulated retrofits’ will drop dramatically. Neither the labour rates of building workers, nor the price of thermal insulation materials have fallen. Recent projects have cost the same in real terms; i.e., adjusted for inflation, as those of the 1980s.





The ‘chainsaw retrofit’, Saskatoon, Canada, 1982.


Picture © Harold Orr.


A+++ Cold Appliances

image13At last, most of the ‘cold appliances’ in Europe are becoming fairly energy-efficient. Indeed, the energy performance of some of them is now very close to the performance of the cold appliances made by Sun Frost in California, USA since 1978.


RF-16 Refrigerator-Freezer.

Picture © Sun Frost, Inc.


A UK Precedent

The UK in fact set one of the earliest precedents for well-insulated, passive solar buildings. Below is the south façade of part of the 1962 extension to St. George’s School, Wallasey.

It had good thermal insulation even by today’s standards; i.e., 125 mm expanded polystyrene outside a high mass structure to absorb and store the high levels of solar gains. The remaining space heating energy demand was much smaller than that of conventional schools. It cost 7-8% more to construct than a normal school would have cost in 1962.



St. George’s School, Wallasey



Source for picture: reference [2]. 



Copyright Credits

Thanks to the various copyright holders for permission to use their pictures in this section of the website. Every effort has been made to identify them all correctly. If there are any errors, please contact EAA and the text can be amended.

Apologies for some of the 1970s photographs on this webpage being very fuzzy. But equally fuzzy, so it seems are peoples’ memories of the work on well-insulated and solar buildings of 40 years ago!




[1] For another account of the rise of the technology of ‘superinsulation’ in North America and Scandinavia, see http://www.greenbuildingadvisor.com/system/files/sites/default/files/History of Superinsulationb-bBC.pdf

[2] See http://www.hevac-heritage.org/electronic_books/M&NW_anniversary/Section-11_StGeorge%27sWallasey.pdf.