Air source heat pump

[deuce22]

Hi.

 

I have temporarily converted my boiler (that’s in the garage) to LPG as I have not yet finished building the house and don’t have a mains gas supply installed yet.

The heating engineer is planning to use a heat only boiler and an unvented cylinder in the house. However, I have just been advised by somebody else to install an air source heat pump. I do not have any idea of how these work or the costs and would like to know if anybody has gone down this route.

The property is an ICF construction and I’ve been told that this is perfect for an ASHP.

As the only other thing that I would need gas for, is an oven and hob, I could also swap these for electric and then I wouldn’t need a gas supply at all. Is this correct?

 

Thanks.

[Nickfromwales]

Search this forum for info on ASHP's, there's absolutely loads to read  

What is your EPC rating? How much insulation? Airtightness result? MVHR? 

There is a shedload of info required before anyone is able to give you useful advice. Input please !  

[Dave Jones]

if you can get mains gas, get it. trust me.

[jfb]

13 minutes ago, Dave Jones said:

 

if you can get mains gas, get it. trust me.

 

I’m not sure he should.

Maybe best to do your own research. 

[pdf27]

As an aside from the boiler .vs. ASHP question, why do you want a gas oven and hob? Ovens are almost 100% electric now and this seems to include all the good ones. Having switched over to an induction hob a few years ago there is no way I'd voluntarily go back - just as controllable, vastly easier to clean and when not in use I can use it as an extra area of worktop.

[Nickfromwales]

There are strong arguments for remaining on / getting grid gas to but it needs a ‘bit’ more thought than……

2 hours ago, Dave Jones said:

if you can get mains gas, get it. trust me.

 

[epsilonGreedy]

6 hours ago, deuce22 said:

The property is an ICF construction and I’ve been told that this is perfect for an ASHP.

 

 

The thermal performance of your new build is what counts, ICF is just one route to the minimum insulation threshold above which an ASHP makes more sense.

 

Underfloor heating and ASHPs work well together although at the highest levels of passiv house performance a little hot air heating via the mechanical ventilation system is enough in which case you could ignore both ASHP and UFH.

[joe90]

3 hours ago, pdf27 said:

As an aside from the boiler .vs. ASHP question, why do you want a gas oven and hob? Ovens are almost 100% electric now and this seems to include all the good ones. Having switched over to an induction hob a few years ago there is no way I'd voluntarily go back - just as controllable, vastly easier to clean and when not in use I can use it as an extra area of worktop.

With our build (ASHP, UFH) Er indoors wanted gas cooking so I had to install LPG, if I had my way we would have had induction, the oven Is electric anyway .

[deuce22]

I’ll take a look through all the posts on here about it then. My SAP rating is 88B. I’m using 150mm PIR insulation for slab and on top of roof rafters. 200mm mineral wool between rafters and the walls are Nudura ICF.

 

For what reason should I get mains gas installed, when It is not going to be used?

 

It was only the hob that would have been gas as my wife prefers cooking on them. I haven’t tried an induction hob, so this is what I will probably install.

 

If I do go the ASHP route, I will fit underfloor heating on all floors.

 

Thanks.

[deuce22]

joe90.

 

So have you not had mains gas installed?

[SteamyTea]

6 minutes ago, deuce22 said:

 

If I do go the ASHP route, I will fit underfloor heating on all floors

Not as simple as that.

Ideally you would need to add extra insulation, which is hard after a building is sitting on it.

[Trex01]

On 04/10/2021 at 12:49, deuce22 said:

Hi.

 

I have temporarily converted my boiler (that’s in the garage) to LPG as I have not yet finished building the house and don’t have a mains gas supply installed yet.

The heating engineer is planning to use a heat only boiler and an unvented cylinder in the house. However, I have just been advised by somebody else to install an air source heat pump. I do not have any idea of how these work or the costs and would like to know if anybody has gone down this route.

The property is an ICF construction and I’ve been told that this is perfect for an ASHP.

As the only other thing that I would need gas for, is an oven and hob, I could also swap these for electric and then I wouldn’t need a gas supply at all. Is this correct?

 

Thanks.

If you house is well insulated and the system is well designed (its important), then you will save a significant amount of money. Just look at whats happening to energy prices right now. They are not going down

[Trex01]

On 04/10/2021 at 16:13, Dave Jones said:

if you can get mains gas, get it. trust me.

Why do you say that?

[Trex01]

On 04/10/2021 at 18:36, Nickfromwales said:

There are strong arguments for remaining on / getting grid gas to but it needs a ‘bit’ more thought than……

 

I think its always good to get a back up ie. gas boiler /elec shower, water only boiler / ASHP heating

 

[pdf27]

32 minutes ago, Trex01 said:

I think its always good to get a back up ie. gas boiler /elec shower, water only boiler / ASHP heating

Only works if it's a genuine backup though - a gas combi won't work without electricity for instance. That means a hot water cylinder is a backup to either gas or electricity to give you hot water during a power cut, but not an extended outage - for which only PV + battery or a solid fuel stove would provide sufficient backup.

[pdf27]

On 05/10/2021 at 11:56, deuce22 said:

It was only the hob that would have been gas as my wife prefers cooking on them. I haven’t tried an induction hob, so this is what I will probably install.

 

If I do go the ASHP route, I will fit underfloor heating on all floors.

1. Might be worth getting a cheap induction hob on eBay or something to try out first if it might be controversial. I got mine (middle-aged NEFF) for £40 from a builder who had ripped it out during a kitchen upgrade, and it can be safely run off a 13A plug so it would actually be really easy to set it up next to an existing gas hob if I had the space.
2. Even with a gas boiler it may be worth going for underfloor heating - no obstructions on the walls for furniture, etc. and higher efficiency since the boiler will be condensing more efficiently. Also provides better future-proofing against an eventual gas boiler phase out or ban - heat pumps will always work better at lower flow temperatures.