Expert 'masterplan' would cut carbon emissions drastically — and put an equally drastic hole in my bank account

There's plenty of room for improvement without busting the budget if I follow the more realistic options, says Alok Jha

There are scores of big and small things you can do to reduce your home's carbon footprint but it is difficult to assess independently how effective each action is relative to another. Photograph: Graham Turner
There's nothing like a detailed plan with timescales and numbers to get your thoughts in order. A month into the plan to green my Victorian home, I've been studying my options and trying to get a handle on which is the most cost-effective, a task that's been made a lot easier by Russell Smith of Parity Eco Solutions. You'll remember him from the film I made last month – the builder with masses of experience in making bog-standard British homes more environmentally friendly. His own home in Carshalton Grove is a shining example of how a private residence can be retro-fitted to slash its energy use.
When Russell came to my house last month, it was to build up a picture of how my brother and I used our energy: how long was the heating switched on for every day? What controls were there on the radiators? Were the walls insulated and doors and windows draughty? What kind of light bulbs did we use? It allowed him to calculate that our expected annual energy use is around 156kWh a square metre and that our house emits around 5.5 tonnes of CO2 a year. Surprisingly, this compares quite favourably with the UK average of 262kWh a square metre for a private home and emissions of 7.1 tonnes of CO2 a year.
You can see a cut-down version of Russell's report here.
Russell said the lower-than-average energy use in our house was due to some of our better habits – switching most electrical appliances off rather than leaving them on standby, only having the heating and hot water on for a limited time every morning and evening and turning off the radiators in rooms that were largely unoccupied.
But there is still much room for improvement. In his audit, Russell identified that we had a much higher than average lighting bill thanks to the incandescent light bulbs still hanging from our ceilings. They accounted for 28% of our energy use when, in an average home, they would be just 7%. The second biggest chunk of energy cost for our home came with the heat we lost through our leaky doors and windows. The draughts in a normal home account for 5% of the energy bill; in ours it was 17%. Thanks to our scrupulous switching-off of televisions and DVD players and relatively new fridge and washing machine, our appliances' energy bills only accounted for 21% of the energy use, as opposed to 32% on average.
What to do with this information though? There are scores of big and small things you can do to reduce your home's carbon footprint but it is difficult to assess independently how effective each action is relative to another. Ranking these can also be difficult if you're on a budget – if you only have £3,000 to spend, which refurbishments have the biggest bangs for your buck?
Fortunately, Russell has attached a "home energy masterplan" to the pie-charts of my home's energy use. The individual actions I can take are grouped into low, medium and high cost and, next to each, is an idea of the payback time from savings in your energy bills.
It's intriguing to see where the house could get to in terms of energy efficiency if I went to town. According to the masterplan if I installed solar panels, triple-glazing and the highest spec internal wall insulation, I'd be looking at a bill of more than £25,000. This frenzy of green activity would reduce my energy use to a quarter of its present value and CO2 emissions from around 5.5 tonnes a year to 1.9 tonnes. You really would have to be purely in it for the environment to take this road, though, as the payback time from your energy bills is more than 30 years at current prices.
The more realistic options in the short-term are the zero-, low- and medium-cost options. By spending just under £1,000 on measures such as installing compact fluorescent lightbulbs, turning the thermostats down on the radiators by one setting, topping up loft insulation to 300mm, blocking off the chimneys to prevent draughts and lagging the hot water pipes, I could reduce my CO2 emissions and energy use in my home by 52%. My outlay would be paid back through savings in my energy bill within 18 months.
If I had a bigger budget, up to £6,000, I could do all of the above plus insulate the solid-brick external walls, seal the floorboards and insulate the ground floor too. This would give an energy reduction of 65% (and a CO2 reduction of 62%). The payback time is longer in this case at 8.5 years.
There is something very powerful about the numbers in Parity Eco's report. By laying bare the problems in the house, it allows you to tackle them in order of importance and get a clear sense of what every improvement is doing.
Before I started this project, for example, I was convinced that double-glazing would be the crucial thing for my house but was blanching at the cost. But Russell's report shows that it might not be the best use of my money: yes, it would reduce my energy footprint but at a cost of more than £10,000 (and that's upgrading the sash windows to UPVC), it would take more than 100 years to pay back the investment.
Much more important are the draughts around the windows and external doors. Seal those and install some heavy curtains and I can get almost all the benefits of double-glazing for a few hundred pounds, a fraction of the cost for double-glazing.
And replacing lightbulbs will clearly add up too. We have around 20 lightbulbs of various types around the house, with an output totalling more than a 1500 watts. This could very easily be cut to 150 watts for the entire house by replacing the incandescent bulbs with compact fluorescent bulbs or LEDs. Take a moment to think about this and it's obvious, but how many of us sit down and total these things up? That would be energy saved every day.
So I now have a plan. Some of the building work will begin early next month – to install the insulation and replace the light fittings around the house so they can accept the low-energy bulbs we want to install. I'll keep you posted.