Friday, 29 October 2010

Mike set to save £500-£600 on gas and electricity

The story so far: three years ago Mike Pepler, our UK Awards Manager, and his wife Tracy, bought an eight-acre wood. This year they bought a house. Now they are heating the house with the logs from the wood.

Since this is the last day of Energy Saving Week we've asked Mike to update us on progress, now he's been in his new house a few weeks. It's going so well, he reckons this year he'll save more than £500 on gas and electricity bills.

Mike writes:

We’ve had our woodburner and solar thermal installation running for a month now, and the loft insulation has been complete for a few weeks as well, so how’s it going?

The good news is that the house certainly isn’t cold. After a bit of experimentation we’ve figured out how to set the stove to burn slowly overnight when it’s cold, and then in the morning there’s a few embers glowing so it can be quickly got back up to full heat if it’s needed.

We’ve found that as the house faces almost south, there’s a lot of solar gain on sunny days, reducing the need to light the woodburner, even on relatively cold days.

The solar thermal is working well, getting the tank up to 70C on sunny days, and pre-heating the water at the bottom of the tank to 30C even on somewhat cloudy days. Combined with the heat input from the stove, there’s been no shortage of hot water.

We’re pleased with the way the heat from the stove is circulating through the house, both by convection and using the radiators. Although the main thermosyphon (or gravity) loop is to the hot water cylinder and bathroom radiator, quite a bit of heat can also thermosyphon to the radiators, which are all controlled by thermostatic valves. This has meant that we haven’t needed to turn on the central heating pump.

Now that we’re only using gas for the hob on the cooker, daily usage has dropped to under 1kWh, which should lead to an annual bill of £25 at most.

When it comes to electricity, the main guzzlers in the house are the fridge and freezer, although both are A+ rated. We chose a “larder fridge” (i.e. no ice box), as this improves efficiency a lot, and our freezer is a slimline version that opens on the top, as this is much more efficient than having a door on the front, which lets the cold air spill out every time you open it. All our lighting is low-energy CFL bulbs, and our computers are energy-efficient laptops. Oh, and we don’t have a TV, though we do use the BBC iPlayer. The upshot of all this is that our electricity usage so far has been a bit over 3kWh a day, so annual usage will hopefully be between 1200 and 1500 kWh, resulting in an annual bill of around £200.

Overall, if our gas and electricity costs come in at a bit over £200, this will be significantly less than the average of perhaps £7-800 for a household like ours.

Of course, we still need to get the wood for our woodburner, and although we’re not buying that, we do have to work hard to get to it, but at least that’s something we enjoy. We’re currently cutting wood for use in two year’s time, after it’s properly seasoned. It’ll be great to see the trees we’re coppicing now growing back next year as well.

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