RefurbN16

Tag: Energy consumption

  • Sustainable Refurbishment – Towards an 80% Reduction in CO2 Emissions

    The UK’s building regulations didn’t start to consider energy consumption until the 1960s, when very basic requirements to conserve energy were placed on house builders. These requirements have slowly been tightened over the decades and the introduction of the Code for Sustainable Homes has accelerated this in recent years.

    The intention is that new build homes built from 2016 will be zero carbon (although the exact definition of ‘zero carbon’ in this case is still up for grabs). The problem is that the UK’s housing stock is the oldest in the developed world, with 8.5 million properties over 60 years old and an estimated 24 million homes built up to 2016 expected to still exist in 2050.

    Zero carbon new build homes are definitely needed so that new homes don’t add to emissions, but all of the carbon reductions will have to happen in homes that have already been built.

    In the previous post we looked generally at a whole house approach to sustainable refurbishment. The Energy Saving Trust has recently published an interesting new publication which looks at this in more detail and points the way towards an 80% reduction in CO2 emissions in existing homes. This guide is aimed at homeowners as well as housing developers and builders and is clearly written and nicely presented.

    It gives an excellent overview of the energy efficiency measures that can be implemented in the UK’s homes including the different types of wall, roof and floor insulation, improving windows and doors, increasing air tightness as well as efficient heating and hot water systems and lighting and appliances. Also covered are microgeneration, water efficiency, waste and recycling and even climate change adaptation.

    If you want to get a good picture of what needs to be done to our homes, then this is a good starting point. Hopefully it will stimulate you to consider which of these measures can be applied in your home.

    The Energy Saving Trust has lots of interesting technical guidance. More information can be found here.

  • Fridge Freezer Temperature

    I picked up a bunch of thermometers this week for TTSN people to check their freezer and fridge temperature. These thermometers are cheap as chips (and apparently reasonably accurate – thanks WRAP) and could save you a tidy little sum if you’ve been overchilling your food. I’ve just popped one in the freezer compartment and it seems to be reading -19 degrees. According to Iceland (and they should know)…

    Star rating Location Temperature Storage
    * Ice box -6 degrees 1 week
    ** Ice box -12 degrees 1 month
    *** Ice box -18 degrees 3 months
    **** Freezer -18 degrees Long term

    So apparently I can store frozen food long term but I don’t really need the freezer compartment as I buy all my food fresh, in small quantities, and eat it straight away. But I can’t turn the freezer part off and leave the fridge part on.

    So what about switching the whole thing off? In winter I could get a cool box and stick it in a shady spot out on the balcony – you don’t want your food (or indeed beer) to be frozen and thawed as would have happened quite a lot this year so a cool box should provide a bit of a buffer.  In summer I think I’d need to switch it back on, but if I could switch it off for half the year…? It seems some are already trying it.

    Of course you don’t want to save CO2 by cutting your fridge or freezer consumption if your food is going to spoil and be wasted.

    I’ve stuck my fridge freezer on a plug in electricity meter to see what it consumes over 24 hours on its current setting. I’ll then increase the temperature and see what the difference is – empirical science going on right here, just for you lucky people!

    1st Results – OK over the last 24 hours my fridge got through 0.4kWh, very roughly suggesting consumption of 145kWh and 80kgCO2 per year. But I checked the temperature in the freezer compartment at one point and it was down to -14. This was towards the end of its off cycle and I’m guessing the -19 reading was taken somewhere around the end of the on cycle. I’ve cranked the thermostat from “3” to “4” and we’ll see what happens (I’m not even sure if it’ll make it colder or warmer at this point).

    2nd Results –  Consumption over 24 hours at the “4” setting was 0.54kWh, a 35% increase. Next I switched it up to “5” and consumption increased to 0.71kWh, a 30% increase again. I’ve now turned it down to “2” and we’ll see how it goes.

  • Measuring Electricity Consumption

    Keeping track of how much energy your home gets through is a very useful thing to do when you start to look at reducing your home’s carbon footprint. By measuring how much energy you get through you can accurately measure how much CO2 your home generates and you can also track the effects that energy efficiency measures have.

    The two energy inputs for most homes in N16 are, of course, electricity and gas. First up we’ll deal with measuring your electricity consumption.

    Start by digging out your old electricity bills going back as far as possible for the house you are in. If you can’t find them, they might be available on your account on your energy supplier’s website.

    Ignore any readings that have “E” or “Estimate” or similar beside a reading as these are guesses made by your energy supplier. By looking at only the customer readings or official meter readings or a combination of the two, you know you’re looking at the actual consumption over that period.

    Each unit represents 1kWh (kilowatt hour) of electricity consumption (I’ll be doing a post on the maths and physics behind energy, power etc soon – don’t worry it’s quite simple!)

    This historical bill data will give you a coarse picture of your electricity consumption – it’ll be low resolution but it’s something. You can take this data and work out average electricity consumption per day across a period and you might be able to see that your electricity consumption is generally a bit higher over the winter months than it is over the summer. But meter readings taken infrequently like this don’t give you a very good picture and you can do much better.

    The simplest and cheapest way of tracking your electricity consumption is to take a meter reading once a week and make a note of it. Even better, upload this information along with your historical meter readings to a website such as The Carbon Account or imeasure. These will automatically convert your electricity and gas meter readings into CO2. I use the Carbon Account as it’s a very nicely presented website and it also allows you to track your transport emissions.

    If you want to pay more detailed attention to your electricity consumption you can purchase clip on electricity meters. These are nifty little devices that clip on to one of the cables coming out of an electricity meter. The box measures the electricity flowing through the cable and transmits a signal to another box which you can take from room to room (mine sits by my TV).

    The accuracy of these devices is so so, maybe to 10W (Watts) or thereabouts, but the main purpose is to see how your home’s electricity consumption changes in real time as you turn things on and off and you can get an idea of how often your fridge’s cooling cycle kicks in and out.  Some people leave it by the door so they can easily see if something’s been left on. Don’t expect to be able to detect every device’s standby consumption with these – it’s really to highlight where the big hitters are.

    If you want to measure individual appliances more accurately then you’ll need a plug in electricity meter. These often display down to 0.1W, although again the accuracy of these can be a bit iffy so you shouldn’t read too much into the readings.  You can also leave them plugged in so that you can measure consumption over a day or a week (important if you’re measuring appliances that operate on a cycle like a fridge or washing machine).

    Electricity Monitor is a useful website that allows you to compare the features of a selection of clip on meters and then buy them. You only really need to have one in your home for a month or two before you’ll have a very good idea of where your electricity is going and then you can pass it on to a friend or neighbour.  Alternatively some libraries are now offering them on loan which is a magnificent idea – you can borrow them in Islington and I might see if I can persuade Stoke Newington library to look into it too.

    Simply measuring your electricity consumption won’t reduce it of course. To do that you need to change your habits – turn off the lights when not in use, don’t run the half empty washing machine, switch things off standby. Alternatively you might see that the old freezer in the corner is munching through the electricity or those last few light bulbs which you haven’t changed yet are getting through more electricity than you thought.

    By making simple changes such as these you can do a lot to cut electricity consumption, but knowing what to change is the first step.

  • Stoke Newington’s Homes

    Most of the homes in Stoke Newington were built during Victorian times.  Victorian homes look great, were solidly built and are long lasting, but energy efficiency was not a consideration in the minds of the architects and builders back in the latter half of the 19th century – it wasn’t until 1965 that energy efficiency became a consideration in the building regulations. It’s worth remembering that back in the 60s, only about a quarter of homes had central heating (6.3 Central Heating Ownership, Domestic Energy Fact File 2008).

    The Department for Energy and Climate Change (DECC) has good data on electricity and gas consumption in homes around the UK. It’s available in chunks of about 2,000 homes known as Middle Layer Super Output Area (MLSOA – an area of the UK used in censuses).

    This data shows that the average home in Stoke Newington consumes 3,600kWh of electricity and 15,700kWh of gas (MLSOA) electricity and gas estimates 2007: London Government office region). The electricity consumption generates 2.0 tonnes of CO2 and the gas consumption generates 3.2 tonnes giving a total carbon footprint for our homes of 5.2 tCO2 which is a little bit below the national average (convert energy into CO2 using the carbon factors found in Guidelines to Defra / DECC’s Greenhouse Gas Conversion Factors for Company Reporting).

    Any home built before the 1930s will most likely have solid walls and these allow heat to pass through quite easily. The cavity in a cavity wall home does a reasonable job of reducing heat loss from a home, even when it’s uninsulated, but solid wall homes don’t have this useful gap between the warm interior and the cold N16 air.

    Another way in which our homes lose energy is through having very poor air tightness. The gaps and cracks in the building’s fabric mean that cold air whistles in and the warm air is forced out. Reducing this unwanted ventilation while still allowing some controlled ventilation in order to keep the air in the home fresh is very important.

    These two areas will be amongst the most significant if we are to reduce the CO2 emissions in our homes by 80% by 2050, however there is a multitude of other aspects of the home’s energy consumption which must be tackled also and we will be describing how each can be achieved in this blog in the coming months.