Sydney University College

Case study: Women’s College at Sydney University

Speedheat installed the first phase of 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.

Speedheat 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.

On a national scale, the potential energy savings of carpet heating compared to space heaters is even more compelling. The National Appliance and Equipment Energy Efficiency Committee of the Australian Greenhouse Office in their product profile on plug in electric space heaters (SB 2004/16 of November 2004), identified current ownership and trends of electric space heaters in Australian households.

Figure 1 below shows the proportion of Australian households by “main” heating type split by fuel type. Note that this does not include data on secondary heating sources which are common in most houses.


Figure 2 below shows the share of main electric space heating by type. It can be seen that electric non-ducted space heaters are the most prevalent in Australian homes, this is followed by non-ducted and ducted reverse cycle airconditioners.
 

 
The national energy costs for electric space heaters and their contribution to greenhouse gas emissions are self evident in an environment where electricity generation is mostly by burning fossil fuels. Speedheat can help significantly with the reduction of these greenhouse gas emissions.
 
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