Jeff makes some good points, BUT he misses a BIG ISSUE:

Having now lived in and renovated two Victorian properties - one big farmhouse and one typical market town terrace - I can say categorically that - for me - cost was not the issue. Double-glazing goes in for COMFORT. Reduced heating bills are a welcome bonus!

Jeff also seems to be unaware of the existence of cost-effective timber double-glazed windows and doors. The
SupaWOOD range is affordable, low-maintenance, and good-looking in traditional properties. It can play a major part in turning  cold, draughty houses into solid, comfortable, modern homes.
  -  KJN - 2015
Energy Efficiency doesn't mean wrecking old houses.

This terrace home in Coventry has been treated to new
SupaWOOD double-glazed rising sashes hung in the original box frames. 

A great way of getting your cake and eating it: 

Insulation can be improved dramatically at minimum cost, and without spoiling the appearance.
home
home
A waste of energy
Should we swap our cherished Victorian terraces for energy-efficient modern homes, as the Government suggests? Jeff Howell questions the logic

Jeff Howell
Sunday Telegraph  11 Nov 2003



Out with the old: The Government is trying to
persuade us that old homes are somehow inferior.
Cast-iron guarantee:
            Victorian guttering can last 60 years

The Government would like more of us to live in new houses.
A steady stream of policy statements - coming mostly from the
Office of the Deputy Prime Minister - has been criticising the
poor standard of British housing stock, and drawing attention to
the fact that it is the oldest in Europe.  The Government's message
seems to be that old is bad, new is good, and that replacing our
old houses with new ones will make us all happier and healthier,
and will save energy, to boot.


Not everyone agrees, however. Stephen Boniface, the chairman of the Building Conservation Forum at the Royal Institution of Chartered Surveyors, says: "Just because a house is old, it does not necessarily mean it is inferior. Victorian and Edwardian houses were generally built with better-quality materials, and using superior methods. That is why they have lasted for 100 years or more. We will be lucky if some of the houses being built today last for 30 years."
And English Heritage is soon to issue a report on the relative costs of maintaining houses from different eras. It will argue that older houses, far from being the energy-guzzling relics that the Government would have us believe, are more energy efficient than recently built ones. The English Heritage analysis revolves around "whole-life costing", which calculates the total cost of constructing, maintaining and disposing of a building, and divides this by the number of years of useful life that it supplies.
Other critics of the Government's housing policies also argue that the new-is-better approach fails to consider the "embodied energy costs" of buildings. As Boniface explains: "Victorian houses were constructed largely with indigenous materials and built by local workers, using muscle power. Today's British houses, by contrast, are built with materials manufactured or processed in factories, transported thousands of miles - often from other countries - and put together on site using machinery and power tools. The input of energy is enormous."
The fact that modern houses use large amounts of non-renewable energy in their construction might be justifiable if they lasted as long as their Victorian predecessors. But the evidence is that recently built homes can start to deteriorate quite quickly.
Among the first items to need repair or replacement are windows. According to Jay Webb, of Fenestration Associates, a collective of window and glazing surveyors: "Victorian sliding sash windows were built from chunky sections of quality, seasoned timber. They were set back from the face of the brickwork, and protected from the elements by overhanging corbels and projecting arches.
"Whereas, in a typical 1960s or 1970s house, the windows are made from thin sections of cheap softwood and mounted almost flush with the face of the wall. They get soaked by every passing shower and it's no wonder they rot after a few years."
The industry has tried to deal with this problem by promoting PVC-U double-glazed windows. Many new home buyers often assume they will be maintenance-free for life, but their performance often falls some way short of this ideal.
Thin-walled PVC-U, with inadequate internal steel reinforcement, can quickly distort, leading to air and water leakage. The hinges and catches on cheaper windows are notorious for early failure, and the problem of misting between the panes is starting to reach epidemic proportions. "If made and installed to the correct British Standards, double-glazed PVC-U windows in new houses should last for 20 years," says Webb. "But too many of them are made cheaply and badly, and are failing after a few years, or even months."
The replacement-window industry is said to be gearing up for a big push to replace PVC-U windows in homes that are 10 to 15 years old. It is delighted by the Government's recent changes to the Building Regulations that require replacement windows in older houses to have the same thermal insulation standards as those in new buildings.

Modern guttering, too, performs less well than the industry would like to admit. Victorian cast-iron guttering lasted for generations whereas today's plastic equivalent is unlikely to last more than 15 years without cracking or leaking, thus allowing damaging rainwater to soak the structure below.
Few period houses have retained their cast-iron guttering; often not because it was past repair, but because builders and home-owners could not be bothered to carry out the small amount of maintenance required to keep it intact, and have preferred instead the short-term option of PVC-U.
There are many other ways in which modern homes can be structurally inferior to older ones. Houses built with cavity walls between 1964 and 1981 are at risk of wall-tie failure. Between these years, the British Standard for the galvanised coating on the steel ties - which hold the two leaves of the wall together - was lowered, raising the potential for corrosion.
More recently, developers have been building homes without a brick or block inner leaf. Instead, a timber frame is used. It is unclear how these houses will perform in the long term, but many new owners express surprise at the lack of plaster on the internal walls and ceilings. Paint or wallpaper is applied directly onto the surface of the plasterboard lining. It is difficult to imagine these poorly protected surfaces withstanding the wear and tear of normal family life for more than a few years without starting to look shabby.
The real folly, however, lies in assuming that tearing down Victorian terraces and replacing them with inferior modern houses will save energy. John Fidler, the head of conservation at English Heritage, questions the "raw assumptions made by decision-makers, such as politicians and housebuilders, that old buildings are a nuisance and somehow in the way".
He says the figures will show that repairing and refurbishing our existing buildings is a far more energy-conscious option than demolishing them and rebuilding using shorter-life materials.Webb agrees: "Developers no longer build houses; they assemble houses, using parts from all over the world. The roofs can come from Germany, the windows from Scandinavia.
"They boast that the houses are quick to assemble and cheap to heat, but there is an enormous initial input of energy in manufacture and transport that is simply not accounted for," he says.
And Boniface asks: "Where is the sense in throwing out centuries of proven construction technology and replacing it with materials and techniques that are untried and untested?"
Where indeed?

COSTS
Guttering: Cast-iron v PVC-U
Comparative costs of a new, 19ft 6in (6m) length of guttering, with stop-ends, brackets, running outlet, 6ft 6in (2m) downpipe, swan-neck bend and gulley shoe:
Cast-iron: 136.
Life expectancy, 60 years (more if cleaned and painted every five to seven years).
Cost per year: 2.26.
PVC-U: 45.
Life expectancy: 15 years.
Cost per year: 3.

Windows: Timber v PVC-U
Cost of overhauling an existing 5ft 8in x 3ft 5in (1,760 x 1,060mm) timber window,
adding draught-proofing and secondary glazing, and allowing for regular maintenance
and painting:
Timber: 415.
Life expectancy: 50 years.
Cost per year: 8.30.
Cost of replacement PVC-U window: 460.
Life expectancy: 20 years.
Cost per year: 23.
Figures from English Heritage