Ground Source Heat Pumps

lostinrates

Cardew wrote: »

I really can't get my head around these figures.


How much are your heating and hot water bills?(not 'general' electricity consumption)


The average is less than £1,000.


Oil is around 6p to 7p/kWh depending on boiler efficiency.


The average system COP for ASHPs was 2.45 on the recent EST trial - and that was with all the manufacturers supervising the modifications to the installations. The majority had a COP of 2.0 or 2.2p.


So assuming you got the average COP of 2.45 that prices a kWh of heat at approx. 4.5p/kWh. With an old house you might well not get 2.45.


Even with our rock bottom interest rates, at 3%pa £20,000 invested in a long term account will still attract £600pa in interest.


It just cannot make economic sense to pay £20,000 for an ASHP.

ATM we have no real functional heating or hot water. :eek: ( we are running electric heaters and have a temporarily fitted cheap electric shower....it would be hard but not impossible to calculate what we are spending on those). But this does bring into question the sense of putting something non renewable ( even without planning leaning on us) and with prospect to be cost effective over time. Is it air?, I don't know, but when looking a putting something in an old house from scratch the costs of things like trenching etc are similar. Gshp are sufficiently more expensive that despite being more efficient I don't think we can juggle finances sensibly to do this in wha you rightly point out, has to be a financial decision as mush as a practical one.

Three winters ago on oil it would have been considerably more than £1k and we barely used it.

To put oil back in here quotes have started at 12k, and the planners are not very thrilled, and we really want them on side! . In real life you are restricted by the prices of the area you live in too, being off grid for everything. Eg, we can put pv in to power the things, but we'd need batteries.....we cannot sell back to grid during the summer. If we could we have enough barn roof space to power much more than our heating.


Anyone reckoning they can heat us efficiently for less is welcome to put in a bid!

lovesgshp

Hi lostinrates.
Without searching back through every post, how many M2 is the house?

lostinrates

lovesgshp wrote: »

Hi lostinrates.
Without searching back through every post, how many M2 is the house?

Um......

Not sure tbh, I'll have to dig out the architects drawings (we're putting in heating to cope with the restored house ).

Its not MASSIVE, its just a farmhouse.

lovesgshp

Thanks, I would be thinking 2 x 16 kwh pumps, then you would be looking @ over 350-400 sq mtrs of heated area.
We have one installation of 350 m2 running 2x11Kw GSHP units on the original rads, with no increased insulation in the house.
Another we quoted on was circa 450 sq mtrs and that required 2 x 17KWH output units. Both were stone built, with no cavity insulation.

lostinrates

I have a neurological condition, and as embarrassing as this is to admit, today I cannot open the filing cupboard drawer, to get out the drawings. I'm guessing about 475 at the very, very biggest ( rounding up room sizes for easy multiplication and certainly overestimating attic conversion space ( just done it on the size of rooms below) .

. Heat loss compromised by five chimneys, and some original windows. As we go through we are increasing insulation internally, a proportion of the build is to restore some of the house which is missing, fell down some years ago. That will be built to modern insulation standards but have a chimney.

We did about 90 sq metres upgrade last year, double glazing and internal insulation almost to modern standard. It has high vaulted ceilings though.



The house also doesn't get much help from the sun, it lies north to south with no south facing windows (ATM). The west side gets toasty though. One of the bonuses is that in summer its deliciously cool.

A further issue with heating it is that it has No corridors. rooms lead into rooms, so there is limited scope down stairs that we can section of onto separate loops as not needing heating often.

Our downstairs is considerably 'bigger' than the upstairs, The area we upgraded so far is all single storey. And is essentially all kitchen and a study. There are two utility areas within that fold too, and a downstairs loo.

Cardew

lostinrates wrote: »

Um......

Its not MASSIVE, its just a farmhouse.
.......


I'm guessing about 475 at the very biggest.

475 square metres is really big for a private house - over 5,000 square feet.

lostinrates

Cardew wrote: »

475 square metres is really big for a private house - over 5,000 square feet.

It's not tiny. But its not a mansion.

Its a farmhouse. Its not a particularly large farmhouse, like a manor farm house for example. Its not however, a small cottage on a farm. I don't really know what to say. I've never pretended its tiny or going to be easy to heat. I have a long thread about my heating problems, and I have said its not a small house, but neither is it accurate for me to portray it as a mansion!

Its....just a farmhouse. Not the grandest nor biggest in my parish, by far.

However, I have lived in a pied a terre about a third of the size of my kitchen.

So.....makes the ashp quote look better to you then?

lovesgshp

With 475 m2, then that would be in the region of the 2 x 16Kw units and the price range you quoted. IIRC, 2 x 17KW GSHP units in another large house (425 m2), we quoted on over here, were circa Euro 28K excluding the excavation works.

lostinrates

lovesgshp wrote: »

With 475 m2, then that would be in the region of the 2 x 16Kw units and the price range you quoted. IIRC, 2 x 17KW GSHP units in another large house (425 m2), we quoted on over here, were circa Euro 28K excluding the excavation works.

For gs?

I just don't think we could get that here at all, haven't found any one quoting anything like that for gs. ( on either system, though we'd need borehole, cannot face the disruption going over the business side, would be too much risk)



Is it cheaper to do over there for some reason?

lovesgshp

lostinrates wrote: »

For gs?

I just don't think we could get that here at all, haven't found any one quoting anything like that for gs. ( on either system, though we'd need borehole, cannot face the disruption going over the business side, would be too much risk)



Is it cheaper to do over there for some reason?

Arggh. Borehole!!! That is the most expensive way ever. You could get the cost down from that another way. These are called compact collectors, which use less ground area than a conventional system. Cost is higher, but less than the borehole solution.
Sorry, I have not got a English version, of the link, but hopefully you will be able to understand what is described. If you run the text through a online translator, then it will give you the basics of what I am describing.
http://www.geotherm.it/Scambiatori_geotermici_compatti.html