Gas connection- is it still worth it?

[ykhan16]

Hi guys- not been on here for a while as my self-build project has been EXTREMELY slow in getting off the ground. Things however are now starting to move with the site now cleared and setting out taking place this week. Long story short hadnt really put much thought into the plumbing and heating side of things besides a short chat with the architect where we decided to go for a system boiler instead of a combi (so hot water doesnt get interrupted). He contacted me last week though saying that if we instead use an electric boiler (which can be partly powered by PV) this would be a 'greener option' and also save £2k on the mains gas connection (main contactor pc sum). Obviously I would never go for the electric boiler so I would have to install an ASHP +UVC so i'm sure upfront cost would still be higher.

 

Builder strongly recommends to have a gas connection over not having one as it gives flexibility down the line- install a gas boiler now and then either replace or use in tandem with an ASHP later. (Wife wants gas for one of the hobs- but i guess we could bottle for that). I've been reading as much as I can on here and the majority who did not get a gas connection was because it would have been pretty  expensive/they were off the grid.

 

For reference

Home is ~200m2. 100 downstairs- HW for wc, utility and kitchen; 100 upstairs -HW for ensuite (shower) and bathroom (shower)
Well insulated with Solar PV system 4.5KW (SE facing)
2 adults, 2 children occupying with occasional guests.

 

Any advice on what makes more economical sense would be really appreciated (note im not prepared to go the DIY route). The ending of RHI and start of the boiler upgrade scheme in April (which I think self builders qualify for) makes things a lot more murkier. First fix scheduled in Feb- 2nd fix April but our builder needs a decision on the gas connection really soon so starting to panic a bit! ? Help!

 

[Temp]

We use 47kg LPG cylinders for a 6 burner gas hob as no mains gas in our village. Works very well. Cylinder gas is expensive per kWH but a hob uses so little that the absolute cost is low. Even when we had kids at home and were cooking a lot a cylinder lasted more than 18 months. Say about £50 a year.

 

[Olf]

24 minutes ago, ykhan16 said:

also save £2k on the mains gas connection

go through the forum, there was a thread exactly on that matter - basically depending on the cost of installing gas line vs savings of using it, depending on assumed payback time it is just a matter of calculation what wins. That ignores environmental as well as comfort (this being very individual) factors though.

 

24 minutes ago, ykhan16 said:

Wife wants gas for one of the hobs

Have you ever tried induction? This summer we had to use gas hobs in the rented apartment - what a waste of summer time it was...

[SimonD]

7 minutes ago, Olf said:

Have you ever tried induction?

 

+1 to induction hobs. I used to be wedded to gas thinking it was the only way to cook properly. Having used induction for the last 3 years, I wouldn't go back to gas again.

[SteamyTea]

Short of hydrogen replacing all mains gas, and that would cost about twice the electrical price per kWh, we are phasing out gas.

 

Just design your house to use an ASHP from the start.  If your architect and builder disagree, asked them to do some long term projections on energy and technology prices, or tell them to stick to drawing and placing bricks in place.

 

[ykhan16]

18 minutes ago, Olf said:

go through the forum, there was a thread exactly on that matter - basically depending on the cost of installing gas line vs savings of using it, depending on assumed payback time it is just a matter of calculation what wins. That ignores environmental as well as comfort (this being very individual) factors though.

 

Have you ever tried induction? This summer we had to use gas hobs in the rented apartment - what a waste of summer time it was...

Thanks Olf- could you point me towards which section it is in? I was looking around all yesterday evening (maybe in the wrong places!) before I posted the thread and couldnt find anything.

 

Yes we are going induction but with a single gas burner. Most of the cooking would be done on induction but there are a a few things an open flame is better for.

Edited November 8, 2021 by ykhan16

[Olf]

14 minutes ago, ykhan16 said:

a few things an open flame is better for

OK, sounds like you occasionally need a barbecue, @Tempmentioned using gas bottles for that.

 

Try https://forum.buildhub.org.uk/search/?q=gas ashp&updated_after=any&page=2&sortby=relevancy&search_and_or=and

Not sure if there is any thread with specific figures, as it is all very relative (even a case study, with members of buildhub doing a lot of diy, may not be representative for general analysis) but you'll  be pointed in the right direction with discussions like https://forum.buildhub.org.uk/topic/21583-cost-difference-between-gas-boiler-and-ashp or https://forum.buildhub.org.uk/topic/23106-get-rid-of-gas-replace-heating-dhw-boiler-with-what

 

 

 

Edited November 8, 2021 by Olf

[ykhan16]

Thanks again for the links and everyone for their replies- been doing more reading and i'm kind of getting snippets of useful info across several different threads as opposed to one.

 

I think i'll try to get a direct cost comparison quote between a system boiler + UVC and an ASHP + UVC, with both UVC's (400litres) having immersion heaters that can make use of the PV energy. I'll have a go at calculating with the spreadsheet what size of system I will need but I'd be grateful is anyone have a very rough ballpark figures for the costs of the equivalent systems given our house size and occupancy.

 

@Temp This is a good suggestion - we would only use a bit of gas so that particular cylinder would last us years! No experience at all with cylinder gas but the one you use seems quite big so do you keep it inside or outside? I assume there is a regulator that you need to attach to it- does this need maintenance/replacing after a period?

[JohnMo]

Just installed a gas combi, with thermal store, the thermal store acts as the buffer for the central heating, through a boiler coil.  Tank thermostat set at 35degs.  UFH uses the thermal store water.  The cold water is fed through the DHW coil to an Atag A325ECX boiler which can takes pre heated water.  The immersion is connected to PV diverter, use surplus electricity, expect to get all my summer hot water for free.  In the winter the combi gets water at approx 35deg so performs well. 

[Temp]

2 hours ago, ykhan16 said:

 

@Temp This is a good suggestion - we would only use a bit of gas so that particular cylinder would last us years! No experience at all with cylinder gas but the one you use seems quite big so do you keep it inside or outside? I assume there is a regulator that you need to attach to it- does this need maintenance/replacing after a period?

 

Outside and there are rules on how near an opening it can be. We have two 47kg cylinders in a metal cabinet hidden behind our garage. Depending on how many rings you have you may need 47kg Cylinders as they have a higher flow rate than smaller cylinders. Our 2 cylinders are on a combined auto change over/regulator device that tells you when a switch over has occurred. Not sure this is essential but I wouldn't want my wife to run out in the middle of cooking Christmas lunch.  For some reason most cabinets are a crazy price (£400-£1,000) so shop around. Ours was just over £200 but that was back in 2007ish. Full 47kg bottles are heavy and really need two people to load in and out of a car so perhaps see if you can get them delivered. Plan a route for how they will be moved from driveway to into cabinet. I discovered you can get quick fit connectors that don't need a spanner to dissconnect/reconnect a cylinder.  Our regulator is 13 years old. not had any issues.

 

 

Edited November 8, 2021 by Temp

[ykhan16]

For reference having looked at the numbers I have opted for mains gas and a system boiler installed. The (none-diy)ASHP option was significantly more expensive even accounting for the cost of connection so I just couldnt justify it.  

 

-The house will be well insulated so space heating requirements should be small.

-Solar PV will primarily be used to heat the UVC throughout the day with boiler for support.

-The UFH and radiators will be designed for future compatibility with a heat pump further down the line.

 

Thanks all for the advice- its been a really useful exercise going through all these options and has brought lots of things to my attention that I should really have considered ages ago!

 

 

 

[Iceverge]

Thanks for the update. 

 

Could you give an indication of the prices you were dealing with? 

 

FWIW I would opt for an induction hob anyway. 

 

[ykhan16]

44 minutes ago, Iceverge said:

Thanks for the update. 

 

Could you give an indication of the prices you were dealing with? 

 

FWIW I would opt for an induction hob anyway. 

 

Of course. Price of gas connection was £2k plus £5k for the gas heating system- ASHP was coming in at over 13k. I will probably switch/add ASHP down the line at some point though but I think at the moment i'm comfortable with this choice.

 

Will definitely get an induction hob with 1 gas burner.

[Iceverge]

Considering you can get an 8kw mitsubishi monoblock for €2.6k plus VAT I fail to see where installers come up with these prices. BTW I opted for direct electric instead of ASHP because of cost too. 

 

29 minutes ago, ykhan16 said:

Will definitely get an induction hob with 1 gas burner.

 

Excellent. You can let us know which one gets used more in practice, free from that all too human condition of thinking ones own goose a swan. 

Edited November 8, 2021 by Iceverge