How to pay less, use less energy, and stay comfortable

This article presents energy- and cost-saving measures, starting with those that are easiest to implement, and progressing to those that require greater investment of effort and/or money.


[There’s nothing stated here about saving the planet, which the evidence shows was formed about 4,600 million years ago, with signs of life about 600 million years later. It’s had its knocks, but when we’re gone, it’ll recover and be just fine. Our hominid ancestors appeared about 2 million years ago – if the earth was 1 day old, we came along in the last 37 seconds, and we’ve only been wreaking havoc in the last 6 milliseconds (six thousandths of a second).


If we burn gas (or oil, or coal), we’re warming ourselves from what bygone life has bequeathed us. This article is about avoiding waste.]


Switch energy suppliers to save money


Loyalty isn’t rewarded these days; it’s penalised. Find the best deals and switch supplier, for example by using


This won’t reduce your energy use or reduce your carbon footprint, but there’s no point paying more than you need.


Compare yourself with others


Getting some idea of how much energy others are using will help you gauge the scale of your own problem.


Live a little cooler


Energy flows from hotter to cooler bodies. If your property is at the same temperature as outside, you’ll need no energy to heat it, however poorly insulated it may be (but you will regardless need energy to heat water for washing). This is how we’d like our summers to be.


The rate of heat loss increases in proportion to how much the warmer is the property in relation to outside.


If you want a tropical environment in the depth of winter, then unless your property is very well-insulated, you’ll burn a lot of gas and pay for it.


Try turning down the thermostat or thermostatic radiator valves TRVs) to see if you can adapt to living 1 celsius cooler. If you can, try reducing the temperature a little further. This can reduce fuel use significantly. (If you don’t have a thermostat or TRVs, read on.)


Check the programmer – when it calls for heat


Take a look at your heating programmer and check that it only calls for heat when you actually need it. Your routine may have changed since the last time the programmes were set.


Close doors


If there are rooms that you don’t need to heat, or can run cooler, close doors so they’re not absorbing heat from the rest of the property.


Boiler – operate for best efficiency:


This applies only to modern condensing boilers and how to keep them condensing (condensing = more efficient).


If water returning to the boiler from the radiators (the “return temperature”) is warmer than about 53C, the water vapour in the boiler’s flue gases won’t condense and energy will be lost via the flue.


Boilers have a thermostat adjustment, which controls the “flow temperature”, the temperature of water leaving the boiler and circulating through the heating system. If yours is a “regular” or “conventional” or “heat-only” boiler (terms used interchangeably), or a system boiler (containing the circulating pump), you’ll need this to be around 65 celsius or more to achieve a stored hot water temperature of at least 60C to kill Legionella bacteria. Some modern boilers read out the flow temperature so adjustment is easy. On older boilers the thermostat isn’t calibrated so without appropriate thermometer’s it’s a process of trial and error to get the tap water hot enough.


If you have a combi boiler, you can set the central heating flow temperature independently of the hot water. This means that you have the luxury of running the radiators at a moderate temperature – you will generally find they don’t need to be scorching hot to make you comfortable.


Although some marketing hype suggests that the condensing boiler rivals in importance the advent of manned flight, in practice the difference between a modern boiler condensing and not condensing is generally around 6%. That’s not staggering, but 6% off your gas bill is worth having, especially if it can be achieved by a minor adjustment.


(The maximum theoretical effect of condensing is around 9%: the fact this isn’t achieved in practice can be seen by the plumes of water vapour from condensing boiler flues on still, chilly mornings.)


Economise on hot water use


Whether you can do this is a personal decision. You can assess your gas usage for hot water out of the heating season by monitoring your gas usage at the meter, or the consumption stated on your gas bill (assuming it’s based on actual and not estimated meter readings).


Fabric first” – insulate and draught-proof


“Fabric first” is a phrase used in connection with conserving energy – it means dealing with insulating the fabric of the building as top priority. Insulation isn’t glamorous, and doesn’t get promoted in the way that “techy” products do, but it gets top score for return on investment. Many of our homes were built in an era of cheap coal and poor comfort, leak heat like a sieve, and have powerful boilers (often too powerful) to heat them. Insulation and draught-proofing can achieve a lot.


Loft and cavity wall insulation and draught-proofing doors and windows are the main measures for existing buildings. Solid wall insulation is also practical and effective. Secondary double glazing is effective on existing windows and delivers good sound reduction. Replacing windows just to get double glazing is a poor financial investment with a very long pay-back time – it’s the draught reduction that principally results in improved comfort.


A thermal imaging camera can reveal the main points where heat is being lost and so pinpoint where effort is best deployed.



Heating controls – programmer, thermostatic radiator valves (TRVs) and room thermostat


In short, get them – they can save you a lot of energy. To have the chance to be convinced, read this:


The fundamental principle behind heating controls is only to call for heat when needed (programmers or timers operate on time) and to stop burning gas when a comfortable temperature has been attained (thermostats and TRVs operate on temperature).


These days, a wireless room thermostat makes sense as its installation is straightforward and involves almost no disruption. Wireless programmable thermostats combine the roles of programmer and thermostat.


Smart controls take things to another level. They can learn your habits (of no value if you don’t have a regular schedule) and allow you to operate the heating via smartphone. For example, if you’ve been away for the weekend you can signal to turn up the heat in time for your return. It can also allow someone away on a business trip to plunge the family left at home into icy cold (well if it floats your boat). Smart controls are perhaps the most significant thing since the invention of the printing press – if you believe their marketeers.


The most sophisticated system I’ve seen allows individual intelligent control of each TRV:


Boiler replacement – fit a modern condensing boiler


Oddly enough, this is the energy-saving measure advocated by those trying to sell new boilers.


If your boiler is really old, it may be very inefficient and you might save a lot of energy by replacing it.


You can look up your boiler’s efficiency in this database:


For example, the Glowworm Fuelsaver 40B mark 2 is given an efficiency of 65%. (Its name may have been appropriate when it was introduced, but time and technology march on.)


A modern condensing boiler with an efficiency close to 90% could save more than one-quarter of the gas bill, with no other changes to the system. Of course, there’s the hurdle of financing the cost of the new boiler and its installation.


Knowledge of current gas usage enables the payback period to be calculated based on current energy prices. For boilers that achieve going on for 80% efficiency, the payback period can be long – longer than the expected life of a replacement boiler. If the cost of gas rises, the payback period shortens.



Weather compensation


Weather compensation is only an option on those modern boilers equipped to use it, and if you’ve had such a boiler installed, you may have weather compensation fitted. The principle is that the heating system responds to conditions outside the property, by using an outdoor temperature sensor, the readings of which are compared with an indoor sensor. If the outside temperature falls, the boiler flow temperature is raised, giving hotter radiators, to enable the property to be heated more quickly, and conversely if the outside temperature rises. Claims of energy savings of up to 15% are made.


Fit a flue heat recovery unit


These are installed between the boiler and the flue and extract heat from water vapour that would otherwise be lost from the flue.


They can be retrofitted but in practice, few people are likely to want the disruption. They are described here (ignore references to the Green Deal, which was mercifully ended in 2015):


Notice the efficiency improvement of 7% is stated as being for hot water. This is because it applies only to combi boilers (which heat water instantaneously with no stored hot water) – most combi boilers don’t condense at all while delivering hot water. As hot water typically consumes less than 25% of total demand (the rest being for space heating), the overall saving on gas may be less than 2%. For a cost exceeding £1000 and £1000 per year gas bill, the payback time would be around 50 years, compared with an expected life of 20 years at most – not my idea of a splendid investment.




Appendix – a trip into (what should be) the absurd


If your gas bill is astronomic, or even stratospheric, turn off all your gas appliances and observe the gas meter. It should be stationary – if not, whose gas are you paying for? An error of this nature is more likely in multi-occupancy dwellings such as flats, where the wrong meter has been allocated to a particular flat – yes I have seen this. “….. when you have eliminated the impossible, whatever remains, however improbable, must be the truth