Energy Saving Advice: How low can you go?

Energy Saving Advice: How low can you go?

Have a good look at the picture below.

It shows how much impact various devices in your home have on your energy-spend. The size of each blob reflects its relative importance.

Some of the details are questionable, for example, where are hot tap water and showers? But the clear message is that heating water massively dominates typical utility spending, and, of that, central heating (oil or gas fired) is the biggest contributor.

The other thing to remember is that a Kilowatt-hour of electricity costs 3-4 times more than a Kilowatt-hour of gas. That makes electric ovens and electric showers a lot more expensive to run than their gas alternatives.

But the rest of this message is about the big beast – water heating and how to reduce it!

ELECTRIC SHOWERS: A 10 kw electric shower will use 2 KWH (70p) every 12 minutes – so 2 showers per day cost  £10 per week or £500 per year. 6-minute showers would save £250 per year, and 4-minute showers would save £370.

Or you could consider switching to a gas powered shower, especially if you have a combi boiler and the shower is not too far away from it.  Or do both – reduce your shower time and switch to gas!


They generally feed 2 separate water circuits with separate controls

Please note – this advice applies mainly to Combi boiler systems (without hot water storage tanks). If you have a storage tank in your system, please follow this link as you need to be sure you’re not encouraging legionella: COMBI  boilers generally feed 2 separate water circuits with separate controls

– for TAPS & SHOWERS (TAP symbol)


  • HOT TAP / SHOWER WATER: Very hot tap water is unnecessary, hazardous and expensive. If you run it cooler (say 50 degress or less) by adjusting the boiler TAP WATER temperature, you will save money and energy because the water left in the feed pipes carries less waste heat, and the boiler can run cooler and more efficiently.
  • CENTRAL HEATING: Water circulates around the radiator system driven by and heated by the boiler.  Boiler systems (and especially condensing boilers) run more efficiently the lower the water temperature they deliver (called the FLOW TEMPERATURE).  If your radiators get really quite hot you should try turning the flow temperature down at the boiler control panel.

This will save money and energy because the heat loss in the feed pipes will be lower, and the boiler will use less fuel.

See how low you can take the flow temperature down whilst still delivering enough heat to your rooms.

If you want to know more about how to manage your boiler settings, have a good look at this excellent guide:

And if you are worried about your energy bills, Warmer Derby and Derbyshire can give impartial advice on 0800 677 1332.  

By Tony Cooper

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