Roofspace: What to do in an energy crisis
The demand for roofspace is only becoming greater as the Australian ‘energy crisis’ tightens its grip. Roofspace is limited, so consumers are seeking the best value for money when choosing roof mounted solar energy equipment.
The average Photovoltaic (PV) system in Australia is rated at 5kW but actually delivers around 3-4kWh over a sunny day. This is approximately 20kWh per day, which is equal to the average daily household electricity consumption without a pool.
A pool can require up to another 22kWh per day to keep it warm and clean*, and 80% of that energy is required just to heat the water. In fact, over 7,000kWh are required to keep a 32sqm pool warm for 6 months **.
Where you get that 7,000kWh of energy from is up to the pool owner – with the common choices being gas, electricity or solar. Do not confuse solar heating with PV solar electricity, or mix pool heating with PV.
Consumers buy PV systems to power their homes for essential living, i.e. cooking, heating/cooling and running appliances. They do not buy PV to heat their pools. However, some pool owners are being told that their PV system on their roof will cover the costs of running an electric heat pump to heat their pool.
This is far from the truth and the resulting power bills usually come as a bill shock. An obvious oversight is that heat pumps quite often run into the evening/night to meet heat demands and this is when tariffs are peaking and the PV panels are not generating power.
In most parts of Australia, the climate and energy required to heat pool water will far outweigh the average 5kW rated PV system. The result is that the homeowner is still paying full price for electricity to run the basic appliances in the house. Even worse, some customers spend the entire output of their PV systems to only half heat the pool. A half-heated pool is an used pool and a total waste of money.
In the energy crisis of the 70s, the solution was to heat pools with solar heating. The answer hasn’t changed in the current energy crisis and it will be the same in the future. Why? Because it’s the world’s most reliable FREE energy source. A solar pool heater will generate up to 0.5kWh. Nothing else comes close. Solar pool heaters collecting thermal energy from the sun extract more kilowatts per square metre of roofspace. The solar pool heater is not helping to run your TV or fridge, but the energy it is generating is free and it allows PV systems to do what they were purchased for. So think twice before bumping the solar system in preference for other solar equipment.
*Data: PoolHeat (UNSW) & Sydney averages, 40sqm solar system.
** 32sqm Sydney Pool, heated for 6 months to 28 degrees, no cover.