Page 90 - Build 161

Roof retro t opportunities:
- 41% have less than 120 mm
- 3% have insu cient coverage - 3% have no insulation
part of the 2015 HCS, a new questionnaire was introduced, commis- sioned by EECA, to capture information on household heating habits. Occupants were asked how and how often they usually heated living areas and bedrooms in winter. The results showed that, while there was a high tendency to heat living areas in winter (mostly in
the evening), this did not extend to bedrooms.
Forty-six percent of households did not usually heat any occupied
bedrooms in winter. In some cases, this included those occupied by older people or young children.
The World Health Organization (WHO) recommends a minimum indoor temperature of at least 18°C in occupied rooms of the house or higher for potentially vulnerable groups. In winter, these unheated bedrooms are at risk of being much colder than the WHO minimum recommended levels.
Range of heating appliances used
In addition to frequency of heating, the type of heater used is a key factor. Heating appliances have varying e ciencies, which a ects both how much it costs to heat the home and how e ective the appliance is in providing a warm, healthy environment.
Heat pumps, electric heating and wood burners
The 2015 HCS householder appliance use survey showed heat pumps and enclosed wood burners – two of the most cost-e ective home heating options – were much more common in owner-occupied houses than rentals. Tenants were more likely to use both xed and portable electric heaters (see Figure 4).
Too many unflued gas heaters
Un ued gas heaters are not only one of the most expensive heating appliances to run but can also impact detrimentally on the indoor environment. The most commonly used un ued gas heater in New Zealand is the portable LPG cabinet heater.
Un ued gas heaters release harmful emissions and water vapour directly into the home, and in poorly ventilated areas, they can reduce environmental quality, increase the risk of damp and mould and a ect occupant health.
Results from the HCS appliance use survey showed 15% of renters were using portable un ued gas heaters to heat living areas in winter (see Figure 4).
Mould in nearly half the houses
A well insulated thermal envelope, good control and management of moisture generated in the home and appropriate heating (frequency and type of heater) are key to maintaining a warm, dry, healthy indoor environment.
Insulated to depth with coverage ≥80%
Insulated to depth but coverage <80%
Not insulated to depth No insulation (3%) No access (14%)
Figure 2: Depth and coverage of insulation in the roof space in all HCS houses. (Source: 2015 BRANZ HCS.)
The installation or repair of foil in existing homes was also banned in New Zealand in 2016 due to health and safety concerns associated with its electrically conductive properties.
These ndings highlight the potential opportunity for improving the thermal performance of a large proportion of the housing stock by tting or upgrading insulation of the sub oor.
Heating habits found wanting
Maintaining a comfortable, healthy indoor home environment relies not only on a well insulated thermal envelope but also on e ective control and management of moisture generated in the home. Heating is a key part of this.
Warming the indoor air lowers the relative humidity. The warm air can hold more moisture, whereas cold temperatures increase the likelihood of condensation forming. A warmer, drier indoor environment therefore reduces the likelihood of damp and mould and the risks these pose to occupant health and wellbeing.
The HCS has routinely recorded information on the presence of di erent heating systems and appliances in New Zealand houses. As
88 — August/September 2017 — Build 161
150 mm or more
120 mm or more
100 mm or more
70 mm or more
33%
2%
47%
3% 14%
39%
3%
41%
3% 14%
57%
5% 21% 3% 14%
66%
6% 11% 3% 14%