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It costs what to boil a kettle? This free home energy kit tells you that and a lot more

You can get your home audit kit for free from your local library

It’s easy to get a bit blase about saving on energy; yes, we are all awaiting with trepidation our winter energy bills, but at the same time, cutting energy costs is not exactly rocket science. Turn off the lights, put on another jumper, cut down on using the dryer etc.

And yet, getting better informed about just how your home is working can pay further dividends.

Step forward Codema’s Home Energy Saving kit, which has a number of devices aimed at helping you identify just where you’re spending your money when it comes to those electricity and heating bills, and how you might cut costs by making some changes.

Since trialling the kit I’ve started to make some changes – pouring a cup of water into the kettle for example, rather than filling from the tap; using a moisture absorber for damp; turning off the TV at night, and finally working on those (bleedin’!) radiators.


And best of all it won’t cost you anything to acquire; you can simply borrow it through one of the 336 libraries across Ireland.

But if doing a “home energy audit” this winter is on your agenda, you’d better get moving and put you name down for a kit; Deansgrange Library in South Dublin for example, says it has about 40 people on its waiting list for a box.

And if you do get a go of it, make the most of the time you have with the box; libraries typically only lend it out for two weeks, so if you really want to make the most of it, start using it straight away.

The box

As pictured, the box comes with a host of little devices, as well as several helpful leaflets, to help you with your home audit.

First out of the box for me was the plug-in energy monitor. You can have a bit of “fun” with this, particularly for those of a more scientific/analytical nature, as it works out how much energy – and thus how much money – certain tasks eat up.

You simply plug the monitor into the socket, and then plug the appliance into this.

Take boiling a full kettle of water. This took 0.157kW of energy, and, given an average per unit cost of electricity of about €0.45 (yes electricity has got very expensive, in case you haven’t heard!), this costs €0.07 each time. Do this five times a day, 330 days a year, and your kettle will cost you about €117 a year to run.

On the other hand, boiling enough for just one cup of tea cost just €0.01 based on energy usage of 0.033kW. Annual costs of about €24.

You could save as much as about €90 a year if you just boiled the amount you will actually use each time. And how difficult would it be to do that?

While running a kettle is expensive, other appliances aren’t so much; take charging your phone. Bringing a dead phone back to life took 0.018kW of energy (or €0.008), which adds up to just about €2.85 a year. And what about leaving the charger in overnight? Well, while there are very clear fire risks against doing this, I found that a new charger left plugged in cost nothing.

However, leaving the television on standby is an expensive mistake. Our TV was on standby for 20 hours in a day; that’s 0.12kW of energy, costing €0.05. Over a year not even using your TV is costing you about €20.

You can go forensic on the plug if you’d like, as my colleague, Jennifer O’Connell, recently did with a similar product.

Next up is the thermal leak detector. You can get the kids involved in this one for some Star Wars-inspired fun, as the gun-like detector sends out coloured beams. The digital thermometer shows where you’re losing heat in your home – it’ll go from green to red, if parts of your home are warmer than the main temperature, or blue for colder parts – expect an immediate blue on external walls, unless you have external insulation. And you can also calibrate the percentage differences.

This is useful to show the extent of a draughty window or the amount of heat you’re losing through your attic. It’s also an indicator of how well your home may be working – after a considerable insulation job in our attic last year, for example, the device shows only a minimal drop in temperature in the upstairs ceiling.

Despite installing new windows and internal insulation, a window on a north-facing wall (adjacent to an en suite) is still inclined to gather too much moisture, which can stain the wall around the window.

No surprise then when the humidity monitor in the kit showed a humidity level of about 80 per cent on the window sill (ideally it should be between 40 and 60 per cent). And this level rose during the night when the window was closed (and even more so when it was raining outside).

It fell, however, when the window was kept open, and on the purchase of a moisture absorber (about €15 in Woodies).

In another room the humidity level rose when a pile of damp washing was set up to dry – no surprise there perhaps – but given the weather of late, it’s a little bit trickier to solve. A dehumidifier is one suggestion here, to keep the excess moisture out of the air, but they do cost upwards of about €200.

This one is quick and easy; just pop the fridge/freezer thermometer on to the middle shelf of your fridge and wait 30 minutes. Then do the same with the freezer. You may find that you will need to do it again to be sure of your reading.

According to the guide your fridge should be set at a temperature of between 3 to 5 degrees, and your freezer at between -15 and -18. Watch out for an accurate reading on your fridge – I found the thermometer in the pack, and the one in the fridge, didn’t always align.

The final part of the kit is a radiator key, which allows you to go around your home and bleed the radiators. We all know it’s something we should do; trapped air can obscure the flow of water through heating systems thus making them inefficient. But do we do it?

Well if you’re like me it’s unlikely, even though it’s in no way onerous. Now is the time to do it when you may not need the heating roaring all day.

To do it you need to have the heating off for at least an hour, and remember to place a basin under the valve to catch any drips.

If you have a newer type of radiator you may not need this key – instead, just grab a Philip’s screwdriver to open the valve.

Fiona Reddan

Fiona Reddan

Fiona Reddan is a writer specialising in personal finance and is the Home & Design Editor of The Irish Times