I'm trying to determine the cost-benefits (if any) of installing a regular
combi-boiler central heating system in my 3-bed semi. The pipework has
already been installed by a previous owner. All I need to do is buy a
boiler hand get it plumbed in. I can istall the rads myself. I already have
some rads. The boiler will be sited very close to an existing 25mm gas
It looks like I could obtain an A-rated combi boiler plus flue kit for
under £500 (Lamborghini Extrema 30C for example). I already have some
radiators I can use.
The alternative method of heating the house would be to use electric fan
heaters, switched on manually, in any room I happen to be using at any
time. I am the only resident.
I think it's safe to assume that electrical heating will continue to be
more expensive than gas over the next decade, however, the fan heater
option means I am only heating one room at a time.
Regarding heated tap-water, I am currently using an immersion heater,
switching it on manually, for one hour before I need to take a bath or
shower. If I installed a combi boiler, I would no longer need to use the
Can anyone give me any clue as to how long it would take to recoup about
£700 in saved fuel costs if I install the gas-fired C/H system?
= 4.5 p/kWh
If you managed to move all your electric consumption to gas at 90%
efficiency, that would add £118 to the gas bill and save £347 on
the electric, giving a saving of £229/year.
Obviously that's not realistic, but you can't do better than that,
and in reality, you'll probably get half that, say £115/year.
You mentioned a loan, and I'll guess you won't be able to do this
for under £1000, which is £80/year interest alone, plus whatever
you pay off the capital.
This is a very crude calculation, ignoring stepped rates or standing
charges, etc, but if you're looking at it purely from the cost saving
perspective, it's not really worth it, certainly when you add in
boiler maintenance and replacement charges.
BTW, what do you currently use gas for, just cooking?
[email address is not usable -- followup in the newsgroup]
firstname.lastname@example.org (Andrew Gabriel) wrote in
Thanks, Andrew. Yes, a crude calculation is all I was hoping for, so the
above is helpful - thank you.
I use a gas cooker. There is also a radiant gas fire in my lounge. I
installed that gas fire last winter, hoping it would kick out enough heat
to warm the whole house and save me £££ on electric bills. Unfortunately,
it doesn't, especially during the coldest months. I don't actually use
the lounge much (1/2 hour a day). I spend most of my time in my study,
upstairs, which is cheap to heat due to its small size. I have a fan
heater with a thermostat, under my desk, pointing at my feet, which works
I keep hoping that electricity will end up cheaper than gas, after they
build more nuclear power stations, but who can tell?
It will always be cheaper than wind and solar, but whether it becomes
cheaper than gas per unit of heat will depend on whether the
anti-nuclear lobby give up. Until they do, we will have to continue
burning fossil fuels to make electricity in the quantities demanded by
the end user.
Burning fossil fuels to make heat to generate electricity to make heat
where you want it can't possibly be as efficient as burning it directly,
all things being equal. Transmission losses alone will see to that.
It seems unlikely... certainly while a large proportion of our flexible
load generation capacity depends on gas (applications nukes and coal are
not well suited to), and especially so while we have to subsidies all
the decorative wind farms and solar panels.
Nuclear electricity is about 8p a unit give or take for new nuclear
Bulk gas is about 5p I think at a putative efficiency of 60% that
translates into about 3p a unit raw cost. I have no idea what domestic
gas costs per Kwh because I don't use it.
Electricity plus heat pump should be competitive..
As should night storage if done effectively - according to EDFS tariff
sheet nightrate electricity is now cheaper than gas.
(in-ep-tocβ-ra-cy) β a system of government where the least capable to
On Fri, 17 Aug 2012 00:01:32 +0100, John Rumm wrote:
Even then I doubt the electricity price will fall much if at all. The
subsi, oops sorry "revenue support", that the government needs to provide
to get the new nuke plants built and the assurances that HMG isn't going
to do a Merkel will ensure that.
Not with the information you have presented so far...
We would need to know what the thermal efficiency of your house is like.
How warm you keep it, what your occupancy level is like etc.
How are you heating it at the moment? What is that costing?
Are you only interested in the lowest possible cost, or is comfort /
ease of use / controlling damp an issue?
The thermal efficiency of house is not great. It has 12" of loft insulation
but half of the house was built in 1850, of solid stone. The other half of
the house has cavity walls, but with only 1"-thick sheets of polystyrene in
the cavities as insulation. Only 50% of the house's windows are double-
I spend about 75% of my time at home. As mentioned, I have been heating the
house with electric heaters, warming only the room I happen to be in at any
The house doesn't really have any significant damp problems.
Cost of heating is the main factor I'm concerned with. To me that's more
important than living in optimum comfort, (say, with the hall, landing and
bathroom continuously warmed).
My KWH consumption over the past year is:
Electricity: 2360 KWh:Cost=£347 inc vat.
Gas: 2554 KWh:Cost=£116 inc vat.
Expect to use twice the gas and half the leccy and it won't be far off, when
I used to run my combi , that's what mine was, although my house is well
insulated, but the DG is ineffective.
 I used to warm the living room, hall (which heated the landing too)
bathroom and 1 bedroom, so 4 rads (from 9) were getting warm, doors kept
shut to the other unused rooms.
This is before I got a woodburner, which now warms the living room, and the
heating doesn't get turned on at all except for maybe a week or two if it
stays well below freezing long enough....last winter I used a quarter of the
gas I'd used the winter before
Thank you.. That's the kind of rough guide I was looking for.
Do you mean you saved 75% on your gas bill just by installing the wood
I have considered getting a wood-burner stove, but I'd have to pay for
firewood (or coal) most of the time. I didn't think that was a cost-
effective way of producing heat, compared to gas..
Yep. the living room is toasty warm even in the depths of winter, but the
upstairs is quite chilly, the general rule is 'dress approproately' IE don't
lounge around in shorts and tee-shirts in December :-p
I'd rather sleep in a cool bedroom than a warm one anyway
I bought 3 bags of coal last November (only got the burner in October) and
I've still got one left unopened, I burnt structural timbers  last winter
and a few logs I purloined here and there but I didn't buy anything other
than the coal, which was used only rarely.
 I and several others in my family are builders, so all decent thickness
timber, like 4X2 and bigger got sawn into 12in logs and burnt, likewise 17
fence panels, 12 mahogany window frames, two cherry trees and a telegraph
pole, along with a t&g shed, half a dozen door frames and various other
It's time consuming for me because I live about 50m from where I can park my
car, so a bit of a trek to get timber to the back garden, but once it's
there, 3 or 4 hours with a table and chop saw combi and I've enough firewood
bagged for the week ahead, that said, I intend using more coal this winter
as it lasts longer and at £7.50 for 25kg it's cheap enough...might go and
get a few bags this weekend actually to get a bit of a stock on.
to be fair this would be my experience also if the house wasn't too
damned big. The aga - about 600-900W continuous heats most of the house
more than adequately for 9 months of the year, and a wood burner heats
the bedroom for the 3 cold winter months. I use the CH to keep the rest
The childhood home had no insulation and was heated solely with a single
coal fire and back boiler.
Tepid baths once a week were the norm.
(in-ep-tocβ-ra-cy) β a system of government where the least capable to
We had a canon gas fire in the living room and that was the only source of
heat in the house, prior to the smokeless act coming in, we too had a coal
fire back boiler, but it only warmed the water in the tank, we didn't have
Ice on the inside of windows was commonplace then, and I can remember my dad
insulating our loft when I was five (42 years ago!) with the new fangled
fibreglass insulation he got from work (they made it and give all workers
free rolls) at the reccomended thickness of one inch - it was still there
when I insulated it 20 years later with the new standard thickness of 100mm
It could be free...
If you have some transport - Just have a chat with a local farmer about
your collecting windfall wood, or find a pallet reclamation place,
local builder about off-cuts of wood from their sites.
If you could find a source of used oil, you could burn that for free. I
use a waste oil burner to heat my garage and workshop.
There are plenty of sources of free fuel, if you are willing to
The new boiler will only use gas when it's turned on. With TRVs
(thermostatic rad valves) you can turn down the unoccupied rooms to
low (but not freezing) and with a programmable stat you can set
different temperatures for different times of day. With a lower level
of even heating you won't be tempted to over-compensate by cranking up
the fan heater.
Except for the depths of winter I find 30 mins central heating morning
and evening adequate. It certainly doesn't get run continuously!
The bottom line is that gas is about a third the cost of lecky.
It might be worth checking the energy saving trust website in the slim
possibility you're entitled to a grant or something.
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