Ditching gas, going electric immersion only, a wee project

michaels

I feel you may be being a bit harsh on yourself.  Just because you are not achieving 100% off peak electric central heating doesn't mean for your usage over the year as a whole it won't be a win.  WE have a bat that won't do all day every day so end up using some peak rate (45.5p per kwh) electricity - ouch - but compared to the saving me make for 90%+ of our electricity being 4.5p off peak it is still a major win.

1961Nick

Solarchaser said:

gefnew said:

Just a random thought but could you use evacuated tube system to also help in using solar gain in the tank with a extra loop coil fitted in the new extra cylinder you are installing.

I could, and I'd really like to, but I can't.

The tanks are under the house, evacuated tubes would need to go on the roof, (wife would definitely not have them on the deck) and when you add in the piping, pump and connections its just too much.

I've tried to have a conversation about a heat pump in the last few weeks when I noted the off peak wasn't enough, but it was a firm no.
She would rather be cold than have a big ugly box thing ruining the look of her garden apparently. 

After me saying the house hasn't been cold, it was cold today, the tank temp was 50C before I noticed and that's enough to maintain temperature, but not enough to bring it up, or at least not in the hour I gave it before switching on the fake fire, the stat was clicking at 16C, and thats no good for wifey.
Fake fire lifted the livingroom up, but I definitely need to sort a controller to kick on when it goes below 60C to get the house to warm.
I set the eddi to heat, but as I mentioned before, that only maintains the temperature when central heating is running, doesn't raise it.
Been between -10 and -6 today, so I dont think that heat pump plus rads would be a good solution for this 1950's house, 50C is just not enough to overcome that sort of chill in today's experience, and there doesn't seem to be too many do over 50C.

What about a small heat only propane boiler as a back up for when it gets really chilly. Would wifey give you permission to put a propane bottle outside the house? It wouldn't need to be connected most of the time & you could store it out of sight?

chris_n

You mentioned earlier that using averages has meant you incorrectly assumed you had enough capacity but the reality of a (severe) cold snap has left the system wanting. You have to consider whether the extra cost of making it larger gives you ROI. It may be less expensive and more efficient to aim for 95% or so and accept that you need external input on certain days. Still a lot of winter to go for your learning curve though. But well done so far!

Solarchaser

Thanks for the comments guys.
Michaels thats a good deal you have there 4.5 and 45p is this still the ovo deal from the v2h charger?
I renew in Feb and its looking like 12p/40p at the moment.
95% of my bought electric has been off peak until the last 2 weeks.

Nick, I hadn't thought about propane, I do still have a couple of tanks from when I used to have a bbq, I think it's definitely worth investing,  I was thinking along the lines of a diesel water heater to boost the heat in dead of winter, but propane would be less messy and less smelly.

Chris yeah I have been thinking the same lines, but if I look at gas use... again averages, not hugely helpful but December,  January and February are my high usage months, so if I assume I need another 10kwh / day for those 3 months, just rounding for simplicity, that's 100 days with 10kwh so at 40p/kwh that's £400.
Another tank is roughly a grand so it should pay back within 3 years.

It's more complicated than that obviously,  the 1000kwh still needs bought, and so at 12p it's still £120 so only a £280 saving, and another tank means extra heat loss too, so potentially more kwh of usage, so it's not quite as straightforward as I'd like it to be, and perhaps some rearrangement of the controls to be more accessible within the house would remove the drive for another tank.... still thinking as I type,  I think really I should have always went with a buffer, and so in all honesty even if it doesn't make total financial sense to have the 3rd tank, I think it makes sense from a ... can't think of the words, I guess mind at rest point of view, I dont want to be having to think if there is someone at home unexpectedly and I've not added extra heat to the tanks, will they be in the house cold (kids home ill from school or similar).

Am I being to hard on myself, hard for me to say, maybe, hindsight is always 20/20, but looking back I really think I should've realised that 36kwh couldn't displace 60kwh even if my boiler was very inefficient,  and when I think of all the time I spent thinking about it before pulling the trigger on buying,  I was definitely getting 2 x 500L tanks, and I changed to 1x 500L and 1x300L at the last minute thinking I'd save some money... haha jokes on the tight jock now eh? 😂😂

1961Nick

Actually the cost of propane even in small BBQ sized bottles isn't far away from mains natural gas.

1Kg = 14.02kWh

Just checked the price for a 47kg refill & it's around £75 ... or 11.38p/kWh

1961Nick

The cheapest LPG boilers are around £500 inc the flue.

A boiler + 47kg bottle would cost less than £800 & you'd have 659kWh on standby + your BBQ bottles as a reserve.

Solarchaser

I had a look also and is about 20p/kwh for the 13kg bottles I have.

I have to do a bit of research, I think on the face of it, for 3 months of the year its a good way to quickly add heat, and would potentially be less costly than adding peak rate electricity which are big plusses.
The minuses are integration, increased complexity of the heating system and of course the return to burning things, which I am trying to get away from on some level.

Thanks though, definitely an avenue to walk through in my mind and a possible solution to these colder days.

1961Nick

Solarchaser said:

I had a look also and is about 20p/kwh for the 13kg bottles I have.

I have to do a bit of research, I think on the face of it, for 3 months of the year its a good way to quickly add heat, and would potentially be less costly than adding peak rate electricity which are big plusses.
The minuses are integration, increased complexity of the heating system and of course the return to burning things, which I am trying to get away from on some level.

Thanks though, definitely an avenue to walk through in my mind and a possible solution to these colder days.

Did I read earlier that you already have 2 x 3kWh immersion heaters in each tank? Adding any more electrical energy to the tanks is surely going to involve some careful load balancing to avoid cooking the main fuse?

After reading this whole thread, I get the impression that you're not the sort of person that fears "complexity".

Solarchaser

You read correctly, there are currently 4x 3kw elements, so 12kw.
I dont plan to increase that draw.
Increasing the off peak to 5 hours from 3 means that I can move the batteries currently charging at 7kw, down to 4kw, that gives the breathing space needed for charging the car at 7kw.
So 12kw elements, 4kw batteries, 7kw car gets me to 23kw in a 25kw fuse, knowing that the zappi and eddi will both limit current to car/element if the current approaches 96a (where I've set the fuse limit in settings).

Adding the 3rd tank means I'll have another 2 elements, but I still only plan to use 4, 1 from each of the 300L tanks and both in the 500L.

Do I fear complexity, yeah not really, you are correct there 🙌, but I do want to be able to say hand on heart that if I get hit with a bus tomorrow,  my family would be able to make it work without me.
Truthfully, I can't even say that right now, nevermind adding the gas on.

Gas adds more dangerous elements,  and is back to burning things (though a whole lot less than the gch).... but it would also potentially remove the need for a 3rd tank, and so less overall heatloss, and that would stop me having to dig a couple of cubic meters on my knees, as well as bucket and barrow it out from under the house and into a skip and that is a compelling argument too.

I'm really "warming" to this idea 😂

Solarchaser

I went off on a meandering through the Internet last night and found this type of thing
https://www.ebay.co.uk/itm/234073487501?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=XB6MEzd_Tl6&sssrc=2349624&ssuid=DtbsXk1pRsq&var=533705260790&widget_ver=artemis&media=COPY

A portable gas boiler.
With a bit of fiddling I could put it on an outside wall, with shut off valves connecting it to the radiator circuit, and a gas tank.
For the coldest 3 months it could be on the house, and for the rest of the year stored with the tank in a shed.

I have to not buy it for a week because I'm a terrible impulse buyer for some things.
But if I still fancy it (or similar) in a weeks time, that will be my next plan.

The wife wasn't exactly keen, but the fact it would only be visible when we weren't using the garden at least got me past the straight out refusal of a heat pump.
Progress 😁