Mould, Asthma and the Electricity Bill
A family of five rents a 1970s three-bedroom terraced house with single-glazed aluminium windows, no cavity insulation and a north-facing rear bedroom. In winter the indoor relative humidity reaches 75–85%; black mould grows on the bedroom ceiling and behind wardrobes, and there is a musty smell. The youngest child, aged 3, has asthma and wakes most nights. Heating is by two 2 kW electric fan heaters for about five hours a day, and water is heated by a 1.5 kW immersion heater for three hours a day. The winter electricity bill was €480 for two months. Net income is €2,100 a month; savings are €2,500. The landlord will not carry out structural work, and the tenancy has two years to run. The family dry clothes indoors on a clothes horse and the bathroom has no extractor fan.
1. Explain the most likely cause of the mould, using evidence from the case to distinguish it from rising damp. (8 marks)
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The pattern points to condensation, not rising damp. Evidence: RH 75–85%, mould on the ceiling and behind wardrobes (cold surfaces), north-facing bedroom, single glazing, no insulation, five occupants, clothes dried indoors, no bathroom extractor. Moisture is produced indoors and condenses on cold surfaces. Rising damp would show a horizontal tide mark at the base of walls, salts, damp skirting and plaster, and would not normally affect a bedroom ceiling. The musty smell and child's night-time asthma are consistent with damp and mould exposure. A simple test: press kitchen foil to the wall for 24 h - condensation on the room side suggests humid air; damp patches on the wall side suggest penetrating/rising damp. A hygrometer and a moisture meter would confirm.
2. Recommend a package of measures costing no more than €2,500, separating low-cost behaviour changes from purchases. Estimate the likely effect on humidity and on the electricity bill, showing your reasoning. (14 marks)
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Low-cost/no-cost:
- Dry clothes outdoors or in the bathroom with the window open and door closed; avoid drying on radiators.
- Open windows for 10 minutes twice a day to purge moist air; use trickle vents.
- Keep wardrobe 50 mm from walls; wipe mould with a fungicidal wash and allow to dry; do not dry-brush.
- Use pan lids, shorter showers, and extractor fan during/after bathing. Purchases (indicative): extractor fan installed €200; dehumidifier €200; hygrometer €10; thermal curtains €150; draught-proofing €80; window film €60; anti-mould paint €50. Total under €1,000, leaving contingency. Effect: reducing moisture sources and increasing ventilation can bring RH from 80% towards 60–65%; a dehumidifier (300 W, 8 h/day) uses 2.4 kWh/day, about €22 over 60 days at €0.15/kWh. Reducing fan heater use by 2 h/day saves 2 kW × 2 h × 60 = 240 kWh ≈ €36; reducing immersion by 1 h/day saves 1.5 × 60 = 90 kWh ≈ €13.50. So the package can cut the bill modestly while improving comfort; the bigger saving is insulation, which the landlord must do. Keep a written record of requests to the landlord.
3. Discuss whether the family should stay and improve the house or move, considering the tenancy, the child's health and the family's finances. (10 marks)
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Stay: the tenancy has two years to run; moving costs deposit, removal and possibly higher rent; the family has €2,500 savings, which is better spent on measures and a contingency. Improving ventilation and heating can reduce mould and asthma triggers. But if the landlord refuses to repair structural defects, the family can request an environmental health inspection and negotiate in writing; withholding rent is risky and should not be advised. Move: if the child's asthma continues despite measures, or if the landlord will not address insulation/extractor, the health cost outweighs the financial cost. A move to a drier, better-insulated home may be justified, but it needs a budget: deposit + removal + first month's rent could exceed €2,500. Decision: stay for now, implement the package, document health and landlord contact, review in 8–12 weeks; move only if there is no improvement or the landlord fails to act.