save energy - cut carbon

Draughts

Draughts are a thing of the past for most of us, but for anyone unfortunate enough to be living in an old house without double glazing, draughts are the main way heat gets lost. Heating a really draughty house is like trying to warm a room with an open door. It’s also one of the cheapest problems to fix. If you can’t afford double glazing or live in a rented flat a few pounds will keep you warmer and probably save you money. Use stick-on draught strips on all your doors and windows. It’s especially important on outside doors but doors from unheated to heated areas can create a big heat loss. Buy “temporary double glazing” plastic film that can be fitted over your windows in the winter – it won’t give much thermal insulation but it will kill off the draughts from old sash windows. It’s easy to fit – using double sided tape to fix it into place and a heat gun or hair-dryer to tighten it up so it looks just like glass – its on sale in most decent DIY stores and well worth the time and effort. Really going to town on draughts will cost no more than £20-30, it will probably save money on heating and will certainly be much warmer.

Insulation

It’s never made more sense to invest in making our homes more energy efficient. Insulation may seem like old news but it surprising how many homes would benefit from upgrading to modern standards. Even in houses with the most efficient heating systems the cost of bringing insulation up to the best possible levels will repay itself within a couple of years. Depending on the house (detached houses lose the most heat, terraced the least – just think “area of wall exposed to the outside world”!) good loft and cavity wall insulation reduce heat loss by 20% each – add double glazing and total energy loss is just about halved. It’s worth noting that very expensive double glazing only delivers a 10% gain in thermal efficiency.

Assuming the house isn’t draughty, insulation is probably the most cost effective way of cutting energy bills - the moral of the story is “insulate before anything else”. Generous government grants mean that costs for cavity wall insulation start from £150 and loft insulation from £200 – little more than the savings they could create from one year’s heating bills.

The grants are not means tested and available to all home owners details at The Energy Saving Trust  and turnkey sites like Enact Energy who will organise a site survey, help apply for grants and arrange for an approved installer to carry out work for you.

Using Lower Powered Appliances

About 20% of domestic electricity is used by lighting - low energy bulbs are rapidly becoming the norm and its a good time to switch old incandescent bulbs - many supermarkets are offering low energy bulbs for pennies at the moment, and they do make a big difference - don't wait for incandescent bulbs to pop - replace them now. There's an urban myth that it takes more energy to switch on low energy bulbs and its cheaper to leave them running - not true!

Keeping lights switched off is the est way of saving energy - a close second is deploying lighting for maximum effect - put the light where you need it.

The lighting rule applies to all the "Stuff" we use. It's worth making sure you use the best energy rated product you can when you replace domestic appliances. An A++ rated freezer uses 85% less energy than an A rated model. It may cost a little more but will save over the product's lifetime.

Fit an energy meter in your home. It can help you identify all the energy vampires - appliances that continue to suck power on standby and make you far more aware of how much power you waste by leaving things switched on.

Old Boilers

Once all your insulation is as good as it can be the next layer of action are the systems that heat your home. If you boiler is old, your central heating system has not been cleaned or maintained for a long time, radiator thermostats don’t function properly and heating control systems are old or even non-existent there is a lot of potential for savings.

An old gas boiler, especially one more than 15 years old it will almost certainly be worth replacing with a modern condenser boiler. Modern boilers run at 90% efficiency, the least efficient old boilers run at 60% - switching can cut gas bills by a third. Cleaning the central heating system, making sure radiator thermostats work and are set at appropriate temperatures for the rooms they serve and effective control systems can all make a big difference to fuel consumption. Assessing your property and your systems is a job for experts – the Energy Saving Trust give detailed information about heating systems, British Gas will make a free appraisal of your home.

There also the possibility of switching from gas or oil to heat pumps - they are costly systems to install but especially if your home is heated by oil or coal, well worth considering.

Home Power

Photovoltaic(PV’s) panels

are springing up on south facing rooftops of homes around the UK – PV’s take sunlight and convert it into electricity using silicon based semi-conductors to produce direct current – that can either be stored in batteries or converted into mains AC voltages by an inverter.

Case Study This installation will produce around 10 kilowatts in full sunlight - but in cloudy conditions would barely power the security light left running in the daytime - the smaller darker panel to the left is solar thermal - less spectacular but far better value for money

In home installed PV’s the electricity can be used directly or fed back to the grid for general use. The government’s feed-in tariff (FIT), introduced in April 2010 provides a significant subsidy for renewable including PV’s that is guaranteed for 25 years. There’s a lot of debate about the value of this scheme. PV’s are very expensive, the energy returned is only about four times more than the energy invested in production and manufacture, and, even with the subsidy, are arguably not profitable (Berners Lee p133 Mackay 39-40). They do generate carbon savings, Mike Berners Lea reckons the lifetime saving on a unit capable of producing 1800 kWh per year would be 50 tons CO2e – a government subsidy of £330 per ton of carbon saved – an extraordinarily high price to pay for carbon reduction.

Some companies offer to fit panels for free in return for 20 or 25 years worth of feed-in tariff income – some allow you the use of the electricity produced – some sell it to you at a discounted rate but either way you are more or less letting the installers have your roof space for free for 25 years – after 25 years the panels may well still work at reduced efficiency but all in all its not a fantastically good deal for the householder.

It's not that PV's don't work - just that the UK is a little too far north and too cloudy for them to be genuinely effective. Fitting rooftop mounted solar panels looks good, but its probably not the best investment to make a real impact on your personal carbon budget.

Wind turbines

Windsave roof mounted turbine PV's don't represent a great energy return on energy invested (EROEI) but small wall mounted domestic wind turbines are almost certainly a complete waste of money. They will probably never pay for themselves or even repay their carbon costs. To be effective wind turbines need to be clear of ground level turbulence and in reasonable wind areas – something that is rare in most urban locations. The B&Q Windsave WS1000 was given an “Eco Bollocks” award from “Housebuilder’s Bible” award winner Mark Brindly and was so useless that the company making it went out of business. The real message about generating your own electricity domestically is that it’s an ineffective way of deploying your resources unless you are off-grid, and that small wind turbines are an especially good way of wasting your money.

If you have done everything possible to make your home as energy efficient as possible and want to invest in renewable it would be far more effective to consider getting involved in a community wind farm or buying into a renewable investment portfolio.

Once the possibilities of energy efficiency are exhausted, solar thermal water heating or heat pumps will generally give more bang for bucks than PV’s or domestic wind – Solar water heating delivers 4 times more energy than PV’s with far lower installation costs.

Solar Thermal

Supplements hot water heating with roof mounted solar heating. Installation costs are half those of PV’s and potential savings far greater. Over 25 years potential savings with high efficiency gas water heating would at least break even but cut electric heating bills by between half and two thirds – both generate large carbon savings.