LONG-TERM COSTS

Research done by the Northern Consortium of Housing Authorities (NCHA) in 1988 into the refurbishment of existing housing with a 30 year mortgage period shows softwood the cheapest option, with upvc and hardwood more expensive.

The Department of Energy pamphlet, Insulating Your Home contains the following Paragraph:

Modern aluminium frames are virtually maintenance free. Their hardwood sub- frames will need occasional oiling or varnishing but this won’t take the time or, trouble needed to maintain traditional wooden frames

The claim that the product is maintenance-free is misleading, for example the life-spans of gaskets, sealed double glaze units, sealants and some ironmongery are all shorter than that of the frame.’ The neoprene gasket which is fitted between the glass and the frame/bead has an estimated life-span of between five and ten years.5 The London Borough of Hackney recently replaced 262 upvc windows with hardwood at a cost of £92,000 because of their inability to obtain the correct replacement components.”

Plastic secondary glazing Professional sealed unit

Professional sealed unit

Table 2, Long term costs (data from Steel

BS 644 timber

Hardwood timber

BS 4573 aluminium

BS 4573 aluminium

BS 4573 aluminium powder coated 95 upvc 110

Self-finish aluminium and upvc frames require regular cleaning, to maintain appearance and painting may be necessary after, 20 years.7

The NCHA suggests that, should the future reveal that there was, one inherent flaw in the concept of upvc windows (something which many architects fear), the major failures may not be due to the frames but to the ironmongery.

The normal product certification by the British Board of Agrément refers to a window life of 20-25 years. What cannot be predicted are the availability of components, the costs of maintenance or advances in technology in future years.

GUARANTEES

Sealed double glazing units are, at best, guaranteed for five or ten years against the failure of the seal.

Guarantees for components offered by manufacturers are not legally binding, so purchasers are relying on their goodwill to fix anything that goes wrong. The only guarantee which is legally binding is that offered by the person with whom they have a contract — the installer. Unless the guarantee is insurance-backed, problems could arise if the company goes bankrupt or is taken over. The new owners are under no obligation to take on guarantees offered by

the first company.’

This case study is one example of what happens when a resident wishes to replace the windows in a house, and illustrates some of the high pressure sales techniques used. In the author’s opinion, people not in possession of the relevant information would be seriously misled by many of the claims.

Whilst it is difficult to compare a plastic or aluminium sliding sash-cum-tiltand-turn window with a traditional timber sash window, on a cost basis it would seem that the plastic and aluminium replacement windows cost much the same as purpose-made timber ones. For the casement window, for manufacturing reasons, timber windows cost far less than upvc and aluminium.

Off-the-peg joinery was the cheapest of all but additional charges would have been incurred if the fabric of the house, or the window, had needed altering.

Neither plastic nor aluminium windows have profiles capable of matching traditional windows, unless it is a very simple casement. At the bottom end of the market, on a DIY basis, standard products would be relatively cheap provided that the correct size of window could be found, but details of glazing bar profiles and pane sizes are unlikely to match.

Modern windows would undoubtedly eliminate draughts and maintenance in the short term, and provide thermal and noise insulation, but this sort of comfort could be achieved much less expensively by using secondary glazing, either fitted professionally or DIY.

In terms of annual heat savings and cost recovery times, installing upvc and aluminium double-glazed windows is almost the least effective measure and costs are not likely to be recovered within the householder’s tenure or even lifetime.

Guarantees of up to ten years are given but their value is questionable. No one knows exactly how long plastic windows

will last. With the plastic window tech __________ nology still in its infancy, using a good

quality traditional material, which offends no one, and a well established joinery firm which understands the necessity of correct detailing, building and maintenance techniques, would appear to be the wisest

7 NCHA study, p45,

Tablel. Installation costs, savings and cost recovery times’

Loft insulation

Hot water insulation

100-150(DIY)

150-250 (contractor)

6-8 (jacket)

Cavity wall insulation 320-450

50-60

50-60

15-30

5-10

Solid wall insulation thermal board

2-3years

1 50-250(DIY)

1,300-1 ,500(contractor)

60-80

60-80

15-30

15-40

Window Association).

20 years

+50 years

Cleaning Total ev cry six

months

Decoration initial cost and Maintenance

12

16

17

17

14

CONTEXT 33