LPG tank - what am I missing?

[Carrerahill]

14 minutes ago, epsilonGreedy said:

 

Did these experiences date back to prior regulation of the LPG bulk supply industry?

Just past and present really. Late deliveries, increasing "delivery charges" - inadequate delivery time-scales, prices which go up in the cold weather, one friend only had one supplier serve his area and the prices became so ridiculous he switched to wood and has never looked back.

 

 

[joe90]

We had  tank LPG  in a park home fir 6 months before our build was complete (in winter) and it cost us a fortune .NOTE standing charge fir electricity heating can be discounted as it will exist fir lighting etc enyway.

[Jeremy Harris]

29 minutes ago, epsilonGreedy said:

 

Because it was a poorly insulated thermal sieve.

 

There is no overnight damper on UFH so I maintain my point that, in anything less than a passiv house, electric UFH will need substantial top up heating at standard rates. The alternative is a much higher slab temperature target at E7 rates and hence an uncomfortably hot house at 5am. Legions of householders have experienced the inherent problems of E7 storage heating, the issues have been well known for 50 years. New builders considering UFH need to be alert to replicating the same problems with an over dependence on E7 heating cycles. In some respects the problem is exacerbated because a new build will shed less heat and short of throwing down 20 kingsize duvets each night there is no UFH damper option.

 

 

No, because the storage heaters did what they are supposed to do, store heat for long periods of time.  If they didn't do this they would be pretty pointless.  Worth noting that all storage heaters automatically close the damper as soon as power is applied, specifically so they don't chuck out heat whilst they are charging.

[epsilonGreedy]

23 minutes ago, Carrerahill said:

Just past and present really. Late deliveries, increasing "delivery charges" - inadequate delivery time-scales, prices which go up in the cold weather, one friend only had one supplier serve his area and the prices became so ridiculous he switched to wood and has never looked back.

 

 

I suspect there are some regional influences in this debate. Lincolnshire is well served with LPG supplier, I will be able to get quotes from 3 or 4 off the top of my head.

 

The balance is shifting towards all electric heating for sure, I just don't believe the differences with LPG are as extreme as suggested. For some who are on a knife edge of being able to fund a self build, the option of an LPG combi coupled to UFH plus a few rads upstairs is rational and certainly better than giving money to Bovis Homes or a landlord.

 

The suggestion of £1000 savings is just daft. If the OP builds a middle sized 160 sqm house insulted to a little better than regs then I doubt we are talking about more than a +/- £400 heating difference depending on the fuel used. 

Edited August 6, 2019 by epsilonGreedy

[epsilonGreedy]

@JSHarrisGiven a 160smq 2 story house built with a thermal performance mid way between Passiv and Building regs heated via electric UFH downstairs and a room target temp of 22 degrees at 8pm and 19 degrees in bedrooms at 4am,  what proportions of UFH space heating KwH will be at E7 and standard rate?

[Temp]

A plug for the energy cost comparison site here.

 

https://nottenergy.com/resources/energy-cost-comparison/

 

Its one of the few that I know which tries to compare the cost per kWH for different fuels. Scroll down to the table. They cite their sources below the table but it is possible to do better than they claim for some fuels.

 

If anyone knows a site with more accurate/realistic data in one table let us all know!

 

I went for oil for heating and LPG (in cylinders) for the gas hob.  If building again I would insulate better and use an ASHP/GSHP. LPG in cylinders is fine for a gas hob but not heating. The cost per KWH is high but the absolute cost is low because you hardly use any even if you do quite a lot of cooking. A 47kg cylinder lasts us at least 18 months.

 

[scottishjohn]

1 hour ago, epsilonGreedy said:

 

What was your heating bill prior to installing an ASHP?

I can tell you ,but really that is of no importance --the fact that energy costs dropped by£1000 is the important bit 

I had a £1500 lpg bill  and when i dumped it my electricity costs went up by £500  -you can,t have abetter comparison than that .,as no other changes were made to the house or its heating system .

 no fancy calculations just real money costs 

 even if you say my lpg system was rubbish --then you still cannot get round cost to use ashp  on a late 70,s tf house --nothing like passiv is£500 for full year in scotland .

 

Edited August 6, 2019 by scottishjohn

[Jeremy Harris]

22 minutes ago, epsilonGreedy said:

@JSHarrisGiven a 160smq 2 story house built with a thermal performance mid way between Passiv and Building regs heated via electric UFH downstairs and a room target temp of 22 degrees at 8pm and 19 degrees in bedrooms at 4am,  what proportions of UFH space heating KwH will be at E7 and standard rate?

 

 

Depends entirely on the heat capacity of the floor slab and the thermal time constant of the house.  A concrete slab acts like a storage heater, with a heat output power that is proportional to the ∆_T between the floor surface temperature and the room temperature.  This makes it somewhat self-regulating, as if the room temperature drops the floor will deliver more heat, so bringing the room temperature up.  When the room is up to temperature the floor heat output will just match the rate of heat lost.

 

Our floor slab has an area of about 75m², so is close to that for the ground floor of a 160m² 2 storey house.  That can store about 4 kWh/°C ∆_T.  If the slab was heated to 4°C above room temperature it would store about 16 kWh, enough to provide 1 kW of output for 16 hours*.  A UFH heated slab like this is broadly the same as an electric storage heater rated at around 2.5 kWh, in terms of heat capacity, but other parts of the house also store a fair bit of heat as well.  For example, our 130m² house stores about 1.6 kWh/°C in the plasterboard and skim, and that provides a useful thermal buffer store of heat that helps to regulate the internal temperature.

 

It's probably possible to maintain a "just meets building regs" house at a comfortable temperature with maybe 70% E7 and 30% peak, using UFH.  Bit of a guess, but I doubt the ratio would get lower than 50/50 even in really cold weather.  With a heat pump with a COP of 3, even 50/50 peak/off peak is going to cost less than 4p/kWh of delivered heat, which is still pretty cheap.

 

 

* Not strictly true, as heat output is proportional to ∆_T, and Newtons law of cooling applies

[SteamyTea]

Just done a quick calculation of my space heating as a percentage of all my energy usage.

Space heating, for the year 2018 was 35% of my total usage.

Total usage was 3,786 kWh for the year.

78% of my total usage was on E7.

[ProDave]

As I understand it, a bulk tank ties you to one supplier, or lets put it another way, can anyone tell me a bulk tank supplier other than Calor?  
If there are others they must be regional as I have never seen any others up here.

 

Even the Cylinder market is suffering a reduced number of suppliers.  As well as Calor we used to have Handy Gas, Mac Gas, Flo Gas and a few others.  All the "competition" seem to have amalgamated into one (I forget which of the names they retained) and the price per refill is withing about £1 of what Calor charge.

 

We have a 47Kg cylinder for the cooker but I would not want LPG for heating.  But then I would not want oil again, that was way too volatile in price.

 

If you house is "too small" for a hot water tank, what about putting it in the loft?

 

Re the cost of an ASHP, first off is to model the heat loss of the house and come up with a real heating load figure, rather than making a wild guess at the size.  Many of us are heating our houses perfectly well with a 5 or 6Kw heat pump.

[Ian]

I built a new-build 71 sqm bungalow to minimum building regs in 2016. EPC is C71. U values are 0.1 floor, 0.13 roof, 0.21 walls and 0.8 windows. No PV or other renewables.

 

It's heated by UFH via a combi fed from an above ground bulk LPG (1400 litre) tank.

 

It's in a very remote area of Wales with no close neigbours and we use it as a holiday home which is one of the reasons why I went with LPG rather than oil as its not as easy to pinch. The heating is normally set to a 'frost' setting of 12 degC and then I remotely boost the heating to normal temperatures on Friday evening when I know we are going at the weekend.

 

The LPG tank was free issue.

 

The last full year of LPG usage was about 420 litres at 33p/litre so about £140 + the £66 standing charge. Thats for all of our heating, hot water and cooking. I reckon about 90 - 100 litres went on hot water & cooking so about 330 litres costing about £110 was the cost of our heating.

 

A full tank contains 1200 litres so lasts us longer than the 2 year LPG lock-in contract period which is handy as it means we are never held to ransom. We have 3 main local bulk LPG suppliers.

[epsilonGreedy]

1 hour ago, ProDave said:

As I understand it, a bulk tank ties you to one supplier, or lets put it another way, can anyone tell me a bulk tank supplier other than Calor?

 

 

Yes but just for two years max. The contract will typically have a fixed per litre price for a portion of the two years and some other formula that specifies a flexible price for the remainder of the contract. I have be advised the fixed price is often a teaser price and I should calculate the two year cost by assuming worst case during the formulaic price period. After the two year period the customer is free to choose another supplier and government regs will determine how much the new supplier pays for the residual value of the tank owned by the current supplier.

 

An ex industry insider told me that the true bulk retail cost of LPG is half the typical tied contract cost and the other half incrementally pays for the tank. Since the true cost of a tank is around a cheap ASHP pro install we are not comparing like for like figures in this thread.

 

[PeterW]

1 hour ago, epsilonGreedy said:

Since the true cost of a tank is around a cheap ASHP pro install we are not comparing like for like figures in this thread.

 

Tanks don’t cost anything to install ..?? It’s about £80-100 per annum, and then the cost of removal is usually around £150 for the uplift. 

 

A decent LPG boiler is £1000, installation another £750 with all the bits. ASHP (non MCS) can be had for £2000, installation about the same as a boiler. Add in an annual service for the boiler at £100, and even without your cost variance, the TCO for 10 years is £1000 more for the boiler when you consider tank rental. 

 

Even a 50% variance on cost per unit would mean that the savings are substantial over the life of the system. 

[epsilonGreedy]

36 minutes ago, PeterW said:

Tanks don’t cost anything to install ..??

 

 

There is obviously a cost, £3000 to £5000 I am told, it is just that the industry reclaims the cost through a substantial fuel markup over multiple years. Clearly these tanks are expensive because it took Government legislation to specify the supplier handover cost of a tank's residual value while promoting customer supplier freedom.