Varying electrical power consumption of gas boilers

[Locoblade]

I was just looking on the SEDBUK website at the boilers Im considering, and I noticed the Vaillant Ecotec 837 Plus has a 6w electrical draw when not firing (as does the 937 - the same model with 15L hot water reservoir?), whereas the smaller 831 and 824 have a 65w draw!

Ecotec 831 Plus

Ecotec 837 Plus

Is that a typo or is there really that much difference between similar models? Also is that the power being drawn all the time the boiler is heating, or is it drawing that 24/7, maybe running the pump all the time? Im assuming the latter as there's also a "draw whilst firing" listed, and if so, an additional 60w draw 24/7 works out about £6 a month extra in electricity cost if the figures are right?!

 

[Agile]

There has never been much interest in the power consumed by boilers as it has been pretty irrelevant in cost terms compared with the combustion efficiency.

I suspect some wrong figures are being quoted.

Most boilers would consume about 6w on standby and about 100w when firing, mostly pump and fan.

Preheated combis and storage combis also lose heat which has to be replemished and that can be 0.3-0.6 kWh of gas per day. That is rarely quoted in any literature.

DONT turn off the power to combis with permanent pilot lights like the Excell 80 as they run the fan slowly to dissipate the pilot heat.

Tony

 

[big-all]

Is that a typo or is there really that much difference between similar models? Also is that the power being drawn all the time the boiler is heating, or is it drawing that 24/7, maybe running the pump all the time? Im assuming the latter as there's also a "draw whilst firing" listed, and if so, an additional 60w draw 24/7 works out about £6 a month extra in electricity cost if the figures are right?!

turn 3 things off each day instead off leaving them on standby and save the 15p a day you loose on your boiler

 

[Locoblade]

There has never been much interest in the power consumer by boilers as it has been pretty irrelevant in cost terms compared with the combustion efficiency.

I suspect some wrong figures are being quoted.

Hi Tony

I suspect some mis-quoting too, the 937 is actually 6.5w so Im wondering whether the 824/831 are also 6.5w but the decimal point has been missed out! If not though, 60w would be significant given the above costs per month which came from a website calculator, £80 a year in electricity would roughly halve the annual gas cost saving on a 3 bed semi with a new condensing boiler compared to running an old inefficient boiler if the figures I saw on SEDBUK are to be believed (approx £150 annual saving).

Regarding power consumption when firing though, interestingly the EcoTec Exclusive has lower power consumption than either of the roughly equivlalent EcoTec plus models (90w against 130/155w for the 831/837) , I guess because of it's modulating pump? Given that the boiler itself modulates output to increase efficiency, Im assuming it may be firing for longer intervals at lower gas consumption than an old style boiler, so even that running cost could become "significant", a couple of quid per month maybe.

Chris

 

[Locoblade]

turn 3 things off each day instead off leaving them on standby and save the 15p a day you loose on your boiler

Yep completely agree, but you can do that regardless of which boiler you fit