new house new combi boiler

older_wiser

I've just moved into a new house with a combi boiler i haven't actually moved in yet so no elect or gas is being used.
are combi boilers supposed to be cheaper ? the only thing i know about them is that the water and heating are instantly on.

my gas and electricity readings are

gas 7353.19 sat
7353.61 sun

elec 23914.5 sat
23917.2 sun

i think i have used nearly 3 untis of elect but i find this odd as i have nothing using elect at the moment. unless the combi boiler uses it.

the gas again i am unsure about as it looks like i havent used much but i have switched all the thermostats down to zero so maybe thats why.

any ideas ?

sheffield_lad

Is it a brand new house? If so the boiler will be very efficent (85-90%), and the insulation will be top notch.

If its an older house check to see if there is an EPC which will give you a better idea of running costs.

As a guide a typical 3bed semi with mr & mrs average use around £110per month for both gas and electric. (electric units average 12-16upd), This time of year of course your going to use more gas than you will in the summer. Combi's are no more or less efficient than a standard boiler. The good point is your not having to heat water for baths etc the negative is baths often take longer to run.

rogerblack

older_wiser wrote: »

I've just moved into a new house with a combi boiler i haven't actually moved in yet so no elect or gas is being used.
are combi boilers supposed to be cheaper ? the only thing i know about them is that the water and heating are instantly on.

In short - combi boiler is almost completely irrelevant.
Typically you may see around 10% tops difference - perhaps much smaller, and often nothing or negative.

Properties vary in their heating requirements for the same external appearance by at least a factor of five or so.

older_wiser

so a combi boiler is not actually an advanatge i thought it was
its a new combi boiler installed 2010 the property has been up perhaps 20 years.

so why would i use 3 units of elect without anything being on ? no tv cooker fridge washer etc these will all be delivered this week.
so whats using the 3 units ? could it be the combi boiler ?

rogerblack

older_wiser wrote: »

so a combi boiler is not actually an advanatge i thought it was
its a new combi boiler installed 2010 the property has been up perhaps 20 years.

so why would i use 3 units of elect without anything being on ? no tv cooker fridge washer etc these will all be delivered this week.
so whats using the 3 units ? could it be the combi boiler ?

Some combis have a reservoir of electrically heated water, to provide instant heat, before the boiler comes up to temperature.
It may be possible to disable this feature.

3 units a week is 17 watts.

This is quite a low figure - a single energy saving light, for example.

It's not completely implausible for the combi to use this amount, even with no stored hot water.

Read the manual for the power draw.
You can also turn all the power circuits off, and see if the meter indicates any draw.

C_Mababejive

No ..combis are not necessarily cheaper. This conclusion is often drawn from all the marketing blurb in which the word efficiency is used. Efficiency in the case of modern high efficiency boilers is primarily used to describe th use of forced draught premix burners to obtain close to stoichiometric combustion.

unclebulgaria

C_Mababejive wrote: »

No ..combis are not necessarily cheaper.

So, I'd love to hear how you came to this conclusion?

rogerblack

unclebulgaria wrote: »

So, I'd love to hear how you came to this conclusion?

https://forums.moneysavingexpert.com/discussion/comment/57404131#Comment_57404131

unclebulgaria

No that's not an answer!
I keep seeing these posts about how a combi isn't cheaper.
I'm interested to hear what technical document you have read this on?
The reason "any" boiler isn't as efficient as the manufacturer states is they cannot be run perfectly, as your link states.
What some are missing is the fact that conventional boilers can be worse with regards to efficiency when they're run or operated incorrectly.

rogerblack

unclebulgaria wrote: »

No that's not an answer!
I keep seeing these posts about how a combi isn't cheaper.
I'm interested to hear what technical document you have read this on?

The cited document in that post.
Several combis were found not to be cheaper.

southcoastrgi

if you look at it a diff way then i tend to agree with UB, while combi's are unlikely to be in condensing mode for long when using hot water you have to take into account the amount of wasted energy with a heat only boiler when it has heated a cylinder full of hotwater which isn't used & will start to cool thus meaning it could req constant topping up & in this instance then a combi may well be cheaper to run.