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

matelodave

Is this going to be installed in conjunction with a heatpump as well or as a stand alone gas boiler as replacement for the one you've got

Reed_Richards

@xander76, ditto.  Is this a gas boiler/heat pump hybrid?  I have just replaced an oil boiler with a heat pump.  I had to replace (almost) all my radiators so I could run them with a lower water temperature.  I don't have gas; I looked at a hybrid with an oil boiler but it wasn't necessary.  I guess that the question to ask yourself is will you save enough money on fuel to justify the additional cost of bolting a heat pump onto a gas boiler?

ccluedo

I am trying to get my head around ASHP costs v benefits/savings.

Even with RHI, is it really it worth replacing oil system with ASHP. (without underfloor heating)?  It doesn't seem like electricity is getting any cheaper!

matelodave

It's certainly not worth replacing a mains gas heating system with a heatpump as the running costs will be about twice or more than gas

The running costs are a penny or two more per kwh than oil oil at the moment. They are cheaper to run than LPG, storage heaters and ordinary convectors or flow boilers.

IMO dont even consider it if you've got access to mains gas. It's a toss-up between oil and an ASHP adn worth considering if you have to use lpg or all electric. The RHI payments which go on for seven years do go a long way towards the extra cost over that of an oil installation but you do need to understand how to use it properly and get it set up correctly.

Dont be tempted or persuaded to just replace a boiler with a heatpump without getting everything else optomised to suit otherewise your be very disappointed both by it performance and its running costs. Do any calculations on a COP of around 2.5 rather thah the 3-4  that some are quoting and you shouldn't be far out.

There are plenty of threads on the subject with lots of opinions (both for and against) so do proper reseach and get several quotations before jumping in.

ccluedo

matelodave said:

It's certainly not worth replacing a mains gas heating system with a heatpump as the running costs will be about twice or more than gas

The running costs are about on a par with oil at the moment. They are cheaper to run than LPG, storage heaters and ordinary convectors or flow boilers.

IMO dont even consider it if you've got access to mains gas. It's a toss-up between oil and an ASHP adn worth considering if you have to use lpg or all electric. The RHI payments which go on for seven years do go a long way towards the extra cost over that of an oil installation but you do need to understand how to use it properly and get it set up correctly.

Dont be tempted or persuaded to just replace a boiler with a heatpump without getting everything else optomised to suit otherewise your be very disappointed both by it performance and its running costs.

There are plenty of threads on the subject with lots of opinions (both for and against) so do proper reseach and get several quotations before jumping in.

Thanks Dave!
Gas not an option unfortunately.
Oil boiler approx 10 years old and currently troublesome. Rads approx 15 years old.
I've had a couple of quotes, and savings over 7 years with RHI of course look good. Not so good obv when that stops.. In both cases I imagine a bit of salesman "padding out" involved.
The quotes are for full changeover so presumably everything required is included and is optimised. How to use it properly might be a challenge tho
Wondering if I'd be better to just replace what I already have.

Decisions, decisions!

richardc1983

ccluedo said:

matelodave said:

It's certainly not worth replacing a mains gas heating system with a heatpump as the running costs will be about twice or more than gas

The running costs are about on a par with oil at the moment. They are cheaper to run than LPG, storage heaters and ordinary convectors or flow boilers.

IMO dont even consider it if you've got access to mains gas. It's a toss-up between oil and an ASHP adn worth considering if you have to use lpg or all electric. The RHI payments which go on for seven years do go a long way towards the extra cost over that of an oil installation but you do need to understand how to use it properly and get it set up correctly.

Dont be tempted or persuaded to just replace a boiler with a heatpump without getting everything else optomised to suit otherewise your be very disappointed both by it performance and its running costs.

There are plenty of threads on the subject with lots of opinions (both for and against) so do proper reseach and get several quotations before jumping in.

Thanks Dave!
Gas not an option unfortunately.
Oil boiler approx 10 years old and currently troublesome. Rads approx 15 years old.
I've had a couple of quotes, and savings over 7 years with RHI of course look good. Not so good obv when that stops.. In both cases I imagine a bit of salesman "padding out" involved.
The quotes are for full changeover so presumably everything required is included and is optimised. How to use it properly might be a challenge tho
Wondering if I'd be better to just replace what I already have.

Decisions, decisions!

Rads will be undersized for a heat pump so will need replacing. You could look at having an air to air system and replace the rads for floor mounted console units that blow warm air (or cool air in the summer) and are really good at heating as they blow warm air out at your feet level. 

matelodave

I've had my heatpump for over 10 years and eleven winters. The cost of my leccy (with nine different suppliers) has varied between 9.5 tp my present 12,25p/kwh (apart from a short spell with Octupus who charged 14.7p for about six weeks after IRESA went bust).

Guessing at a COP of 2.5 means I've been paying between 3.8 to 4.9p/kwh over that period. I've had £5k back from the RHI (last payment is next week).

Have a look at this - it doesnt necessarily answer your questions but should give you summat to think about as it was originated by someone who has replaced oil with a heatpump - https://forums.moneysavingexpert.com/discussion/6240076/i-bought-a-heat-pump/p1

richardc1983

matelodave said:

I've had my heatpump for over 10 years and eleven winters. The cost of my leccy (with nine different suppliers) has varied between 9.5 tp my present 12,25p/kwh (apart from a short spell with Octupus who charged 14.7p for about six weeks after IRESA went bust).

Guessing at a COP of 2.5 means I've been paying between 3.8 to 4.9p/kwh over that period. I've had £5k back from the RHI (last payment is next week).

Have a look at this - it doesnt necessarily answer your questions but should give you summat to think about as it was originated by someone who has replaced oil with a heatpump - https://forums.moneysavingexpert.com/discussion/6240076/i-bought-a-heat-pump/p1

Is yours air to air? I was told I couldn't have the RHI payments. 

matelodave

No,

it's an 11kw Daikin Altherma split ASHP which is heating an overlay underfloor wet system in a 140m2 bungalow together with a 200litre hot water tank

We actually installed it three years before the RHi came into effect so as far as I was concerned the RHI was a bonus rather than a consideration when we chose to have the heatpump.

Our RHI is based on a deemed COP of 2.5 and the EPC calculation, although I believe that nowdays the RHI is based on the calculated COP given on the MCS certificate and EPC heating calculation and is therefore worth more if the calculated COP is higher

The heatpump replaced eight manky rusty storage heaters (for which I dont have any cost info as we ripped them out the day we moved in) 

Mickey666

matelodave said:

No,

it's an 11kw Daikin Altherma split ASHP which is heating an overlay underfloor wet system in a 140m2 bungalow together with a 200litre hot water tank

We actually installed it three years before the RHi came into effect so as far as I was concerned the RHI was a bonus rather than a consideration when we chose to have the heatpump.

Our RHI is based on a deemed COP of 2.5 and the EPC calculation, although I believe that nowdays the RHI is based on the calculated COP given on the MCS certificate and EPC heating calculation and is therefore worth more if the calculated COP is higher

The heatpump replaced eight manky rusty storage heaters (for which I dont have any cost info as we ripped them out the day we moved in) 

Fair enough, but a heat pump is always going to compare favourably with other forms of electric heating.  It's like going from a 'really expensive' form of heating to a 'quite expensive' form of heating and ignoring all the cheaper forms of heating available.

What was the cost of the installation and how long did it take to recover that cost based on your savings?