Cheaper to boost or heat overnight?

ConfusedMan999

I have recently moved into a new flat and it is electric only. I have never had an electric immersion heater before and I am unsure what is the best option for me. It's a 'Horstmann economy 7' boiler.

I live alone and only really need hot water to wash the pots and get a shower each day. I don't have electric storage heaters, they are just plugged in at the wall so I don't need the boiler for them.

What will cost me less, letting the boiler heat over night on the cheaper rate, even though I only need enough water for a shower, or using the boost feature each day before I get a shower?

Sorry if this is the wrong area, I'm new here.

matelodave

Just turn the hot water on for an hour or so before the E7time runs out (say about 5am) so you've got plenty of hot water for morning ablutions and for the rest of the day. There should be enough hot water left for another shower in the evening if that's what you want.

Heating your water during the boost period will cost you twice as much as heating it during E7 time

Just experiment a bit with the timings but a decent tank should stay hot all day - you could put another insulating jacket over the insulation that's already there.

It's obvious, but a 10 minute shower takes twice as much water and energy as a 5 minute one, so keep them short. Don't waste hot water by letting it run down the sink - rinse stuff (including your hands) in cold water. A fow restricter on your shower head and hot taps will also reduce your consumption of hot water.

Every time you run off half a gallon of cold water to get the hot tap running hot you leave half a gallon of hot water sitting in the pipework, wasting heat.

I'm still trying to persuade my wife that rinsing a yoghurt pot in hot water is significantly less eco-friendly than just chucking it in the recycling bin with a quick cold rinse or no rinse at all.

victor2

As above, experiment a bit.
Read your meter at the same time each day for a week or so, and try different methods of heating your water.
It's not difficult to work out the cost of the electricity used on each rate.
Allow a few days with each method, so that things settle down and you'll eventually find the best balance of cost against availability of hot water.
OR, join a local leisure centre and do a work out or take a swim there daily, followed by a shower in their facility. That will cut down your hot water requirement at home.

EachPenny

victor2 wrote: »

OR, join a local leisure centre and do a work out or take a swim there daily, followed by a shower in their facility. That will cut down your hot water requirement at home.

That might work out more expensive than the immersion heater - for real money saving you could just wait until it rains and then go and stand outside

I'd agree with matelodave's advice - an hour or so of heating during the E7 period should give you enough hot water to see you through the day. If you don't use much then the water would still be warm the day after.

At the moment I'm spending about 11p per day on E7 electric, which is providing all my hot water plus running a fridge and freezer and some lighting/computer use. I estimate all my hot water is costing 10p per day.

You'll probably find it better to shower in the morning rather than the evening, but if an evening shower is preferred and you find the water is a little too cold in the evening then try increasing the amount of time the immersion heater runs for during the E7 time.

In a 'worst case' situation you can use the boost facility, but if the controller is the type I think it is then as standard the boost runs for one hour. You will probably only need about 5 mins of boost heat to get the water steaming hot again, so don't just let the boost timer run to the end, switch it off as soon as you've got enough hot water.

ConfusedMan999

Thanks for the advice, and that does make more sense, having it heat for an hour on the cheaper setting but I don't believe I can do that with the model of boiler.

The only options I have are a switch which is either off or 'Timed' and the boost button. If I flick the switch to timed it heats the water over the preset E7 period.

EachPenny

ConfusedMan999 wrote: »

Thanks for the advice, and that does make more sense, having it heat for an hour on the cheaper setting but I don't believe I can do that with the model of boiler.

The only options I have are a switch which is either off or 'Timed' and the boost button. If I flick the switch to timed it heats the water over the preset E7 period.

You should be able to adjust the hours of operation during the E7 time period, but how you adjust it will depend on the model you have.

It sounds to me like you have something like this one -
http://www.uk-plumbing.com/horstmann-economy-7-quartz-timeswitch-e7-p-42267.html

Is that right?

Richie-from-the-Boro

ConfusedMan999 wrote: »

Thanks for the advice, and that does make more sense, having it heat for an hour on the cheaper setting but I don't believe I can do that with the model of boiler.

The only options I have are a switch which is either off or 'Timed' and the boost button. If I flick the switch to timed it heats the water over the preset E7 period.

Your twin element [probably on a Hortsmman controller] does not work like that. The timed / boost 60 minutes top element is at full day rate and the bottom element heats a whole tank at the cheap rate.

coffeehound

ConfusedMan999 wrote: »

I have recently moved into a new flat and it is electric only. I have never had an electric immersion heater before and I am unsure what is the best option for me. It's a 'Horstmann economy 7' boiler.

I live alone and only really need hot water to wash the pots and get a shower each day. I don't have electric storage heaters, they are just plugged in at the wall so I don't need the boiler for them.

What will cost me less, letting the boiler heat over night on the cheaper rate, even though I only need enough water for a shower, or using the boost feature each day before I get a shower?

Sorry if this is the wrong area, I'm new here.

Hiya. Are you definitely on a dual-rate price tariff?

Does your meter include a radio switch to turn the water heater on when it's in 'Timed' mode? Sounds like it is from what you say above.

Have you checked the temperature that your water heater is set to? If not it would be worth getting it checked to make sure it's not set too high. 60 degrees C is reckoned to be best as long as that gives you enough hot water.

With that set, and if you are on an Economy 7 etc dual rate tariff, then it shouldn't cost significantly more to leave your water heater set to Timed as the thermostat will then switch off when the water is hot enough.

If you are going to use ordinary heaters during the peak-rate hours next winter, however, it could work out cheaper to change back to single rate billing then, as the heaters will cost more than your water heater to run.

Richie-from-the-Boro

Bacteria are dormant below 20°C and multiply between 20-45°C and nutrients are available. So 60°C is essential. Rate of loss [leeching] is as coffeehound says minimal 150 litres of cheap bubbling hot water every night is a fractional cost in the summer and about x2kWh in the winter, not really a loss in the winter of course because that heat goes into your home anyway.

ConfusedMan999

Richie-from-the-Boro wrote: »

Your twin element [probably on a Hortsmman controller] does not work like that. The timed / boost 60 minutes top element is at full day rate and the bottom element heats a whole tank at the cheap rate.

From what I understand if I set the switch to timed it will heat the full tank over night during the lower rate hours, which are between 12am and 7am for me. Then there is a separate knob for the boost which I can use any time I like and that heats the smaller top tank. Is this correct?

I do have the Hortsman controller, and after googling it seems the 'timed' mode is pre-set, unless I want to unscrew the front of the unit and figure out how to change it that way, which I think is more a job for the installer.

After some playing around I have found that it is pre-set to come on at 3am and heat the tank until 8am. It's only during this time that the 'Off peak' light on the unit lights up.

Richie-from-the-Boro

My suggestion is just leave well alone and it will do what you want by default. Don't mess with attempting to adjust the internal pin settings. The 7 hours is a total, precisely when varies and is irrelevant, 7 hours is 7 hours, the thermostat will regulate the required input without your intervention.

Again you will never need the 60 minute boost function, I've never needed boost in 35 years plus. If you ever did use boost function .. .. the controller will throw an isolater on the other auto function. One or the other but never both. So yes you are correct in your assumptions. Best of luck.