Efficient boiler programming

em3943

Hi there,


so we recently had a new oil-fired boiler installed. It has an integral water tank which it keeps "topped up" so there is alway shot water available, but it seems that is does this 24hrs a day - which just seems so inefficient!


Does anyone know / have experience of whether it ends up more efficient to run it like this, or to turn it off and just have hot water when you actually run a tap/shower? For background, during summer we only really need hot water in the morning (for showers) and possibly a bit for washing up if it doesn't all fit in the dishwasher! In my brain it just seems wasteful to have it heating the water all day and night for such a small amount of hot water usage but maybe it is the more efficient way...?


Advice much appreciated!

matelodave

Keeping water hot when you don't need it can't really be more efficienct than just heating the water when you do.

Most of us dont keep the kettle hot all day and all night just in case we want a cup of tea, so why do it with a boiler.

Unless you can measure the amount of time the boiler is running, or the amount of fuel that it's using in either mode and compare then it's difficult to actuallyknow what the cost difference might be.

EachPenny

Can you post the make and model of your boiler?

Having the integral tank may preclude it, but if you are only really using hot water in the morning and not using central heating in the summer you might be better off using Economy7 electric with an immersion heater to meet your summer needs. Might be too late to add that facility though.

Cardew

EachPenny wrote: »

Can you post the make and model of your boiler?

Having the integral tank may preclude it, but if you are only really using hot water in the morning and not using central heating in the summer you might be better off using Economy7 electric with an immersion heater to meet your summer needs. Might be too late to add that facility though.

My assumption was that the boiler is a Combi, thus there will not be a hot water tank and immersion heater.

EachPenny

Cardew wrote: »

My assumption was that the boiler is a Combi, thus there will not be a hot water tank and immersion heater.

I did wonder, but the OP mentions an 'integral water tank' which sounds a bit more than a run of the mill combi type boiler. Even so I doubt the internal tank would have a immersion boss, but thought it worth asking

Edit: It comes from growing up in the countryside where you always think of a plan 'B' - relying on an oil fired boiler as your only source of hot water would be against my principles!

Cardew

EachPenny wrote: »

I did wonder, but the OP mentions an 'integral water tank' which sounds a bit more than a run of the mill combi type boiler. Even so I doubt the internal tank would have a immersion boss, but thought it worth asking

Many Combis these day have a small internal tank to enable hot water to reach the taps quicker. It is a facility that can be switched off.

The majority of oil-fired combination boilers have an internal hot water store to supply domestic hot water.

A disadvantage of using the internal tank is that the boiler can fire up in the middle of the night and disturb people.

em3943

Thanks for all the replies so far!


So our new boiler is a Grant combi boiler, I believe it is a "Pro Internal Combi" one but not sure on exact model.


My understanding is that it has a small water tank inside it (we don't have a separate large water tank) which is so that you get hot water much quicker on demand. There are two "rocker" switches on the boiler, one for heating and one for hot water. Each can be set to constant, off or timed. The heating is set to timed and run by the thermostat timer. Tater is set to constant as the thermostat we got when the boiler was installed (the one recommended by the installer) is single channel, so not able to do timing for hot water.


My gut feel is same as Matelodave - given how little of the day we need hot water on demand it must be more efficient to get a timer which can programme hot water to be on only when needed and not 24hrs?? But I wondered, given it's a new boiler and supposedly eco-friendly why there is a "constant on" option for water. And that made me wonder if maybe the theory is it uses a negligible amount of oil to keep it on constant so no point changing it??


I just wondered if anyone had a similar style boiler and had any experience of whether it would be better to have the hot water on a timer similar to the heating?


Thank you!

em3943

oh, and no - no immersion heater... We were led to believe that the new boiler would be the best option for us, and hopefully it will be once we've sorted the best configuration....


I have been thinking maybe when we get the main bathroom re-done (likely next 3-5years) we could get an electric shower put in? So we have a back up which avoids using oil entirely during summer!

Cardew

em3943 wrote: »

Thanks for all the replies so far!


So our new boiler is a Grant combi boiler, I believe it is a "Pro Internal Combi" one but not sure on exact model.


My understanding is that it has a small water tank inside it (we don't have a separate large water tank) which is so that you get hot water much quicker on demand. There are two "rocker" switches on the boiler, one for heating and one for hot water. Each can be set to constant, off or timed. The heating is set to timed and run by the thermostat timer. Tater is set to constant as the thermostat we got when the boiler was installed (the one recommended by the installer) is single channel, so not able to do timing for hot water.


My gut feel is same as Matelodave - given how little of the day we need hot water on demand it must be more efficient to get a timer which can programme hot water to be on only when needed and not 24hrs?? But I wondered, given it's a new boiler and supposedly eco-friendly why there is a "constant on" option for water. And that made me wonder if maybe the theory is it uses a negligible amount of oil to keep it on constant so no point changing it??


I just wondered if anyone had a similar style boiler and had any experience of whether it would be better to have the hot water on a timer similar to the heating?


Thank you!

With a combi, including a Grant oil combi, there is no need for a timer for hot water(HW). If you don't want the boiler's small internal (HW) tank to heat up, you simply switch it off. You then heat water on demand - the whole purpose of a combi. The only penalty of switching off the HW tank is that it will take longer for the HW to reach the taps.

matelodave

In my view, if you've got a combi boiler then you dont need timed hot water - it should heat it on demand when you turn the tap on.

Likewise you don't need a programmer for the heating, a programmable thermostat is a much better option as you can control it to give different temperatures for different times of the day and for different days of the week.

I'm guessing that heating your shower using an oil combi boiler would be cheaper than using an electric shower on peak rate leccy although I'm sure you'd need to do some clever sums to work out how much oil the boiler uses for a five minute shower compared to the power used by an electric shower for the same period. The leccy calculation is easy but I dont know about oil as there are a lot more variables to take into consideration.

em3943

Thank you both - I think we'll give it a go with hot water "off" and see how long it takes for it to pull through to the shower (upstairs) then.


With regards the heating, it is a programmable thermostat that we have (if my understanding of what that means is correct) - as in different periods of the day are set to different temperatures rather than being either on or off.


Slowly I learn more and more about the house!