Time to start thinking of draught-proofing and insulating our homes against the onslaught of winter. There are a host of measures that can be implemented, from small cheap and easy DIY measures, to work that involves more expensive upheaval. But the more you pay, the more you expect to save off your heating bill, right?

Sally Phillips of Chimney Sheep Ltd had a look at the range of measures recommended by the Energy Savings Trust, and worked out what the payback was – and the results were surprising; it’s the aggregation of marginal gains that are going to give you the most effective results:



Cost to fit Cost saving per year Payback time
1 Hot water tank lagging


15 130 1.5 months
2 Chimney draught exclusion



(Chimney Sheep Ltd)


(Chimney Sheep Ltd)

6 months
3 Loft insulation (where there hasn’t been any at all) 340 180 23 months
4 Pipe lagging


10 20 24 months
5 Cavity wall insulation


465 150 37 months
6 Suspended timber floor insulation


525 60 105 months
7 Loft insulation top up


275 20 165 months
8 Internal wall insulation


8,750 245 429 months
9 External wall insulation


15,000 245 735 months
10 Double glazing



(The Eco Experts)

80 1713 months

All data is taken from the Energy Savings Trust website except where stated otherwise. Figures are averaged over the various house types given.

  1. Hot water tank lagging – if you haven’t got your tank lagged then tut tut! These are easy to buy and easy to fit. Like putting a cardigan on a baby. Hot water tank jackets are available in most DIY shops. You can also get more environmentally-friendly ones filled with sheep wool, from
  1. Chimney draught excluder – most of us are unaware of how much warm air is lost up chimneys. This is mostly because we can’t see or feel it, but we certainly notice the cold draughts from air pulled in to replace the warm air travelling up the chimney. The EST recommends various draught-proofing measures but it is difficult to find data on how much these save you. Chimney Sheep Ltd has had the product tested by BSRIA to determine their cost savings which are quoted above.
  1. Virgin loft insulation – you definitely should have this! Up to 25% of heat loss can be through un-insulated lofts. So, in theory you could up to 25% on your energy bills.
  1. Pipe lagging – unless you regard the exposed pipes as a way of heating your home before it reaches the radiators / taps, then get your pipes lagged. It’s so easy it’s almost fun, and so cheap you hardly need worry about the payback, but worth it nonetheless.
  1. Cavity wall insulation – of the “bigger” measures, this is the cheapest and easiest to do. But it’s not suitable for every house.
  1. Suspended timber floor insulation – up to 15% of household heat is lost through the floor and although it would take nearly nine years to recoup the cost, it will make your home more comfortable and prevent your toes from getting cold – and you’ll be able to wander around barefoot in the house, even on the coldest days.
  1. Loft insulation top-up – although it’s not going to save nearly as much as putting insulation into a loft that has never been insulated before, it’s still going to make your home a lot cosier for a relatively low out-lay. It’s almost true to say – you can’t have too much insulation in your loft!
  1. Internal wall insulation – this is getting expensive. Don’t think about payback, just think about how much cosier your home is going to feel. Up to 35% of household heat is lost through uninsulated walls.
  1. External wall insulation – same as above
  1. Double glazing – I don’t think we should think about fitting double glazing as a money-off-your-bill exercise. The maths simple don’t add up. The EST provides figures for how much it could save, but no estimates for fitting it (which they did for the other products, except for draught excluders). Double glazing will save you some money off your bills, but will take years to pay for itself. However, it will make your home more comfortable, reduce draughts, and it looks nice too.


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