Warm Solutions Speedheat Sydney installed carpet heating in the 1894 Main building of Women’s College at Sydney University, which was refurbished during the 2008/9 summer vacation. The College identified the existing 1.2 – 2.4 kW oil filled space heaters as a major source of energy consumption at the college and investigated more energy efficient heating options to reduce costs and hence greenhouse gas emissions.

Using an average room size of 10m² which was heated by a 1.2 kW oil filled space heater, the energy consumption per hour for the existing college room heating was calculated as follows:

280 rooms x 1.2kW = 336kW. (As the baseline - there are also larger rooms with 2.4 kW heaters) Assumed energy tariff = 12cents/kW hour. Therefore: 336kW x 0.12 = $40.32/hour Assumed hours of heater use per day = 12 hours. Therefore: $40.32 x 12h = $483.84/day The energy costs per month and the contribution to greenhouse gas emissions are self evident.

The oil filled space heater is a low capital cost investment but a high running cost option, which when assessed on a twenty year life cycle costing will prove to be a very expensive heating option. These heaters radiate heat over a relatively short distance and rely on convection to warm the room. With convection, the warmer air migrates to below ceiling level, causing the cold air to drop to floor level, creating drafts which aggravate air borne dust and hence asthmatic symptoms. The feet (which are the thermometers of the body) remain cold; causing the room occupant to sit close to the heater and these temperature extremes increases the occupant’s susceptibility to colds.

The Speedheat system offered an energy efficient option: New carpets were installed as part of the refurbishment and a carpet heater of adequate heating capacity (10m² x 50W/m² = 500W) was installed between the carpet and the underlay in each room. This provides heat at floor level with a diminishing temperature gradient above. The 485W heaters are controlled by thermostats in each room. The energy consumption per hour for the new college room carpet heating can be calculated as follows: 280 rooms x 0.485kW = 135.8kW x .12c/h = $16.30/h x 12h = $195.60/day. This is a saving of $288.24/d for the same user criteria. Clearly user management in terms of energy wastage and heat losses is the key to further savings.