Conservation

The cost of conservation

By Bruce Maunder Taylor

ecently, I received one of

Rthose questionnaires from a University student doing his dissertation on energy conservation in buildings. Are buyers and residents aware of the need? To what extent do costs and potential savings influence them? Do they review their standards periodically? Do they actually do anything about it? I mentioned it to one of my local estate agents who made an unfortunate remark about the usefulness of Energy Performance Certificates and the paper they are written on.

Many blocks of flats have installed energysaving light bulbs. Why? To save energy costs? To reduce the frequency of bulb replacements? To increase security by having the lights on longer without increasing the cost? To help to protect the environment and reduce the carbon footprint? The reasons are mixed; the answer is ‘it depends’.

CAPITAL COST

When the un-insulated flat roof of a block of flats has to be renewed and the surveyor recommends high quality insulation, how often is a calculation made showing the additional capital cost compared with the annual savings?

One of the hidden problems is the tendency draught proofing to doors and other openings, and then complain to the managing agent that there is a water penetration problem that is ruining all the new decorations. The managing agents (or their surveyor or builder) report that it is condensation. The lessee (or their tenant) denies it and an unnecessary dispute arises.

Air, at a particular temperature, can hold a corresponding amount of humidity or moisture. If the temperature rises, the humidity can also rise. If the temperature reduces, then humidity levels will fall and excess humidity must condense. In outside conditions, condensation results in dew or frost. In inside conditions, condensation will affect both the coolest surfaces and where there is least air circulation. Typically, this will be on windows, on un-insulated ceilings, and behind cupboards placed close to outside walls, etc. Sometimes, a flat occupier comes home from work, turns up the heating, cooks, breathes, has a bath or shower and generally promotes warm, moist air. The occupier then goes to bed, gets up in the morning, boils the kettle, turns the heating down, checks the windows are securely shut to avoid burglary risks, and goes to work. Condensation, possibly severe, can result.

EXCESS HUMIDITY

The problems with condensation are not limited to excess humidity. A tell-tale sign of condensation is the appearance of spots of black mould on wall, ceiling and other surfaces. Mould reproduces by releasing spores into the air, which then settle on other damp surfaces to grow new mould spots. Humid air carries a larger amount of bacteria and viruses than dry air. Lack of ventilation means lower oxygen levels. The conditions that are ideal for condensation are the same conditions, which will cause the occupiers to wake up feeling groggy and tired in the morning, have persistent coughs and/or sore throats, and an increased risk of asthmatic-type problems.

It is important to be able to reliably tell the difference between condensation and penetrating dampness. If it is condensation, it is important that the occupier adequately ventilates the flat with the ideal standard being three air changes per hour. That may not be energy efficient in the most stringent sense of that phrase, but that has to be balanced against the health of the occupiers of the flat.