UPDATED: Air Source Heat Pumps/Air Con - Full Info & Guide, is it cheaper to run than mains gas?

zeupater

Diallingtone wrote: »

Running costs so far....

I've just had my electric bill in for the period 6th June to 6th December - it makes interesting reading (for me, at least!). During that period I've had to take the following into account:
* My first summer with solar PV (3KW system)
* 8.5KW Ecodan fitted on 18th August
* Ecodan doing all HW and heating instead of immersion heater and LPG
* Solar thermal also offsets HW, but that was in last year as well

Up to 6th June, I was paying £80 per month for electric and was £150 in credit. To 6th December, I'm now £180 in credit. So in that 6 months, my electric payments have stayed the same, but I've saved 6 months of LPG payments at £120 per month (£720).

That's encouraging - obviously the next 6 months will be more telling; less solar PV and more heating cost. I'll have to wait 6 months for the next exciting installment.

Interesting to read Nande's post - I don't actually know what my settings are or how to change them, but would be equally keen to know if there is a sweet-spot set up that we need to aim for.

I can also testify to -5º outside with lashings of hot water and warm rads inside.

Cheers,
Mark

Hi

£80/month electricity with heating being via LPG at a further £120/month ? ..... £2400/year before ASHP/pv , but including solar thermal ? .... have you insulated and installed other energy efficiency measures yet ? .....

Just as cold here overnight and we're still only using the burner which is currently averaging less than a basket of logs/day (~15-20kg) ... it'll take a couple more nights at a mere -4C to effect the internal temperature here and I would expect that to be the same for any well insulated high thermal-mass structure, the difference in energy requirements only really becoming apparent as the internal structure (mass) starts to cool and needs heat replenishment ....

HTH
Z

Diallingtone

zeupater wrote: »

Hi

£80/month electricity with heating being via LPG at a further £120/month ? ..... £2400/year before ASHP/pv , but including solar thermal ? .... have you insulated and installed other energy efficiency measures yet ? .....

I was thinking about fitting windows...

lovesgshp

JC_Derby wrote: »

Depending on the start up current, this can introduce flicker onto local networks, the DNO would be quite within their rights to ask you to uprate your supply or remove your HSP.
better to check before installation, at no cost than have problems down the line.

Most heat pumps now, have soft starters on them to prevent that type of occurrence, so would have no effect on other properties.

zeupater

Diallingtone wrote: »

I was thinking about fitting windows...

... probably the first place to start ...

Seriously though, at £80/month (~7000kWh/year) you seemed to be consuming well over double the national average electricity (3300kWh) for properties with alternative forms of heating and LPG purchases at £120/month suggests around 18000kWh.t for heating, which looks to be marginally above the national average for gas heating (16500kWh.t) for all housing stock.

Recent investment in solar thermal, pv and ASHP seems to suggest a better than average position on moneysaving/climate/green issues (whichever is the driving force), however, the consumption figures seem to suggest that the low-cost basics were not in place prior to the obvious significant investment, or am I reading it incorrectly ? ... were the improvements part of a complete building renovation which included insulation improvements ?

Z

lovesgshp

gterr wrote: »

Ha Ha, Geotherm: At a loose end now you've fixed mine?? (49kW last 24h here, and never got above freezing outside. Nice and toasty inside. Better not gatecrash this thread, though....)

Lol, no, have plenty of things to do!!! We are still getting to finalise your setup, but at least it is better.
Have sent you a PM, with how to access the pump running times, so you can see how many hours a day it is actually working.

JC_Derby

Geotherm wrote: »

Most heat pumps now, have soft starters on them to prevent that type of occurrence, so would have no effect on other properties.

indeed someof them that i come across are unbelievably low.
good thread this though

lovesgshp

JC_Derby wrote: »

indeed someof them that i come across are unbelievably low.
good thread this though

Of course this is a good thread, as there are lots of informative people about :T

Diallingtone

zeupater wrote: »

at £80/month (~7000kWh/year) you seemed to be consuming well over double the national average electricity (3300kWh) for properties with alternative forms of heating and LPG purchases at £120/month suggests around 18000kWh.t for heating, which looks to be marginally above the national average for gas heating (16500kWh.t) for all housing stock.

Recent investment in solar thermal, pv and ASHP seems to suggest a better than average position on moneysaving/climate/green issues (whichever is the driving force), however, the consumption figures seem to suggest that the low-cost basics were not in place prior to the obvious significant investment?
Z

Well I've done what I can. I have loft insulation, albeit over 7 years old - British Gas are coming out in Feb 2013 to beef it up or replace it as part of the free grant scheme. I have double-glazing throughout. I have replaced virtually every bulb with low energy variants - recently having swapped out 23 x 50W GU10 halogens with 3.6W LEDs.
I live in a 70's built timber-framed house and there are compromises; the lounge ceiling is only insulated by old-fashioned electric blankets and there's nothing I can do about that (the ceiling goes straight to tile outside). The walls are insulated with rock wool, but I doubt that's as good as cavity wall insulation. The hot water tank is lagged.

I work from home, so my daytime usage is probably above average.
Am I missing any other big ticket items?

Cheers,
Mark

John_Pierpoint

I am not sure I can visualise it - can you post a picture?
Have you got a "live ridge" and a sort of "Cathedral" effect ?

I renovated my present hovel in the mid 70s, and the local builders thought I was right off my trolley when I put in 4" of fibre and upped it to 6" over the living room. At the time the regulations required 2" and that was just about to be increased to 3".

You can remove all the tiles then replace them over trays of insulation fitted to the rafters.
PIR is roughly twice as effective inch for inch when compared to fibre.

You could have some fun playing with this link

http://www.celotex.co.uk/Other-Resources/U-value-Calculator

[Other brands are available]

It is not cheap, but should be cheaper than a bigger heat pump; but if you don't do it you may find yourself not qualifying for goodies like RHI

It is only a matter of time before stick joins carrot

Are you sure British Gas - Centrica will still do it for free after 1st January ?

TiredGeek

nande2000 wrote: »

Eco temp set at 38 deg c at 5 ambient and 45 degc at -5. Any other settings it is recommended to tweak to improve performance.

Ours is set to 33'c @ 20'c ambient and 50'c at -10'c, these numbers seem to work very well for our drafty old place,we could probably lower the 50 to 45 and still be comfy though it might take longer for temp changes indoors to happen, like 16' daytime up to 20' for evening.
DHW set at 55', boosted to 60' by immersion once a week.

We just spent a week at the hovel and the Ecodans worked superbly in getting the old place from 10' up to 20' and keeping it warm all week. One night we got down to -11'c outside while we were at a lovely 20' inside, and the following day the temp outside never went above -5'c
Consumption has averaged 38kWh/day per unit (one works more than the other, so total averaged and divided by 2)...
Not what you'd call cheap at ~£10/day but substantially better than our friends oil system and not bad for a big drafty old farmhouse in the frozen north
We're not fussed about spot consumption, we're taking it as a twelve month period and so far it's looking cheaper than estimated so we're chuffed.

As for "global warming" and "carbon emmisions"....
1/ I'm old enough to remember in the late '70's when all the renowned scientists had proof that global average temps had been steadily dropping for the last 200 years or so and we were shortly entering a new ice age.
Now those same renowned scientists have proof that global average temps have been rising for 200 years...blah blah.

2/ You could shut Britain down for a year and reduce our carbon emissions to 0 and during the same time just the increase in emissions by China OR india would more than cover what we saved.
The average UK consumer has sod all impact on emissions globally and the amount we save by spending the huge amounts the government does is pretty pointless whilst emerging economies continue to increase their output expotentionally.
We're about tenth in the world for emissions.

The planet goes through periods of temperature change naturally, it was far warmer in the UK in the twelfth century than it is today, yet I'm pretty sure we didn't have all that many cars back then