The Energy Audit

The new decade will be hopefully best remembered as the time that we woke up to the fact that we need to start living within our means and start managing the scarce resources that the earth provides us to live with. This issue we take a look at how we can achieve this, starting with the place where you can make the most impact in reducing your carbon footprint as well as saving money: your home.

Making an energy audit of your home is basically assessing how much electricity your appliances use and calculating the amount of insulation in your house to see how much is escaping due to poor insulation. An energy audit will give you a picture, often quite frightening, of how much energy is being wasted and the lack of energy efficiency in appliances and insulation.

Making An Energy Audit
It is quite straightforward to do an energy audit on a home. It is easy to buy a power metre that measures wattage used by different appliances when you plug them into it. Every thing should be included – washing machine, dishwasher, TVs, stereos, even the electric iron. Many of these appliances suck up energy, even when they’re just on standby – if you ever needed an incentive to make sure appliances are fully off when not in use, an energy audit will do the trick.

Lighting can make up almost one-third of an electricity bill, and although this can’t be measured with a power metre it is quite easy to get an estimate. Simply multiply the number of hours each bulb is on each day by the wattage (60 watts multiplied by four hours comes to 0.24 kwh or 240wh, for instance). Do that for every single bulb in the house and you have one day’s usage. Multiply that by 365 to come up with an annual figure, then calculate your cost by multiplying it by the electricity rate. Khalifa Saber of Pretasol recommends changing over to LED lighting wherever possible. “Low energy bulbs are a great replacement over incandescent ones, but LED is even more energy efficient and will pay back the investment many times over.”

To put that in a real world context, imagine a security light on a house, or garage wall with a 100-watt incandescent light bulb. Let’s say it is left on all day, every day for the whole year. Then suppose that bulb is replaced with an energy-efficient LED light bulb. How much is that going to save you? A 100W incandescent light bulb left on 24 hours a day, 365 days a year will operate for 8,760 hours each year. Multiply the wattage of the bulb by the number of hours it operates, the bulb consumes 876,000 watt hours of electricity. One thousand watt hours is a kilowatt hour and is the unit of measurement that most utility companies use to charge you for electricity. So in this case, the bulb uses 876kilowatt hours (kwh) per year.

The LED light bulb you install uses 10% of the electricity of the incandescent bulb. By changing the bulb, your electricity use falls from 876 to 88 kwh per year. If you pay 12 cents per kwh your annual bill for this single bulb will drop from €105.60 to €10.56, a saving of €95.04 per year.

The solar revolution
Solar water heaters are a vastly underused technology considering the potential here in Spain. As an energy saving device they reduce the need for electricity or gas in providing hot water for the home. Solar water heaters can provide 50-80% of the hot water needs for typical homes and businesses. As oil and natural gas become increasingly rare and therefore expensive, more and more people will turn to the sun to meet their energy needs. Hot water consumes about 30% of the average household energy bill according to the Junta de Andalucia. As natural gas production declines and prices climb the cost of hot water is expected to rise dramatically. Retrofitting a home for solar hot water could save a lot of money and also help to alleviate the strain on the energy production cycle as a whole.

With grants available for anyone installing solar systems there is an added incentive, and companies like Pretasol will include the grant in the price. “Basically the client pays for the system at the discounted price, and we claim back the grant from the Junta, making it easier for the client,” continued Khalifa.

The savings made by starting to apply energy saving measures and buying energy saving devices could run into tens or hundreds of thousands of pounds over a lifetime. Even for people thinking of installing renewable energy technologies in the home, the first step should be to run an energy audit of the home and put in place energy conservation tactics. This will make the task of running the home from renewable energy easier and cheaper. Why spend €30,000 for a solar electric system, when a €2,000 investment on energy conservation means you only need to install a smaller, cheaper system costing €15,000?

Pretasol 952 794 655

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This post is also available in: Spanish

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