Oil or Gas Boiler

ham1sh

Hi,

I was considering a Ground source heat pump, but for various reasons, we've pulled out of that particular project. Cost being one of the major factors.

Anyway I'm looking at installing either an Oil fired or Gas boiler, fed from external tank, and was wondering which would be the better option?
I have been advised that gas boilers are really efficient these days and it would probably make economic sense in the long term to go down this route. Is this sound advice?

Cheers
hamish

Phil57

Have you considered air source heat pumps?

ham1sh

I've been looking at all the options, including Air source. I don't want to go for this as they apparently stop working when it gets too cold.

I've been advised that I'd be cheaper with oil compared to LPG, as I'd have to pay tank rental for LPG.

I've heard about the RHI scheme that is being introduced next April, so ground source is back on as a contender again.

The running costs i've been supplied are as follows:

Oil £1623/yr
LPG £1774/yr
Elect £3000/yr
Pellets £1466/yr
Peat £1945/yr
Heat pump £750/yr

So, outwith the higher initial costs, the heat pump seems to be the best option.
There's a lot of scare stories going around regarding GSHP's, as it seems a lot of people are paying incredibly high electric costs and not getting any heat. This seems to be because the system was specced incorreclty or installed badly.

Is there any way that I can work out the amount of ground loop, size of heat pump required myself? That way when i get the quote, i'll know if the guy knows what he's doing?

Hamish

johntheexpat

I can't help with advice about costing it yourself, but the sales pitch from GSHP people does seem to consistently give an overly rosy picture.

As I understand it, the efficiency of the system, COP, depends on the difference between the ground temperature and the output temperature from the pump.

So, the sales-bunny will quote you for say, a ground temperature of 10C (or whatever) and an output temp of 45C and will give you an impressive sounding COP that can then be shown to give you great savings.

However, realistically for heating you will need a much higher output temperature, unless you have absolutely state of the art insulation.  This higher output temperature will badly skew the COP and then all the other figures on which you have based your choice will start to collapse like a house of cards.

Throw in the cost of the system and depreciation, along with running costs and maintenance and the equation becomes much more difficult.

One area where air source heat pumps really seem to be holding their own and producing impressive results is with heating swimming pools.

It may be that your best option is along the lines of an air source heat pump for most of your heating needs, but a tacit acceptance that it will have to be backed up with electric heating during really cold snaps.

The trouble with this is that the future costs are guesswork.  Oil and gas seem certain to rise considerably.  Wood pellets are anybody's guess.
Peat - presumably you are not going to tell any environmentally active friends that you are burning peat?
Electricity will always be available, since society will collapse without it so it will always be an option, but at what price?

Personally if the costing works, I would opt for an Air Source heat pump with a pellet burner back up.
But that is what would suit me and may not be an option.

ham1sh

Thanks for the advice.

The insulation should be pretty good as it's a new build, and will need to conform to current building regs.

I'm having a meeting with the architect tomorrow to discuss changing the kit to allow for under floor heating. Apparently they can lower the joists.

I don't like the idea of having a system whereby I will also require to have a back-up, as is the case with Air source.

I intend to get a quote from a few companies up here and see how they compare. Not just on price, but on the amount of ground loop they estimate will be required.

I also intend to ask them for contact details of other customers, so I can call them up and ask how their systems performed over the winter, which was really quite long and hard, compared to previous years.

I agree with what you say regarding the GSHP salesmen. They can be quite evasive when asked direct questions, especially regarding COP over the Winter months.

Hamish

ham1sh

Well,
I've managed to get in a few quotes in for the GSHP.
The problem is, they are wildly different. One guy is saying I need a bore hole as there's no room in my garden, and another is saying the opposite!

Is there anywhere I can go for independant advice on this?
It's just too big a project, and too expensive to get wrong.

Cheers
Hamish