@jeff whats the efficiency is your boiler? Its worth taking that into account as it will increase your unit cost for a kw of gas.

Posted by: @batalto

@jeff whats the efficiency is your boiler? Its worth taking that into account as it will increase your unit cost for a kw of gas.

92% Seasonal space heating energy efficiency for the boiler. 

So 2.75 would equate to 2.99 for gas. 

So electric (assuming 100% efficiency) 5.12 more expensive than gas if taking into account the efficiency of the boiler. 

@jeff certainly those numbers don't stack up unless you have some kind of PV system to make a large portion of the hot water element "free"

Posted by: @batalto

@jeff certainly those numbers don't stack up unless you have some kind of PV system to make a large portion of the hot water element "free"

Just my personal thoughts. Every home will be different and i am no expert....

I suspect the numbers would come out relatively similar for anyone with a fairly modern mains gas condensing boiler right now, even with the recent increase in energy prices as both gas and electricity has gone up. The multiple will be around 5.

Installing solar PV would obviously reduce my bills with a mains gas boiler (less daytime electricity from the grid for general electricity use, could still perhaps use for some water heating, could sell back the excess electricity via the grid, etc.). Although I agree there would be some additional benefit from solar PV if i installed a heat pump. 

There are a lot of houses that may have to accept higher bills unless we can get the price of electricity down. 

Then there is the additional cost of a heat pump, installation, upgrading insulation, upgrading heat emitters etc. The annual service costs are also higher with heat pumps as are spare parts and repairs outside warranty. Insulation improvements would also help with a gas boiler, but are more critical with a heat pump i understand. 

We need to move away from fossil fuels that is a fact, and fossil fuels were going to run out one day anyway. I don't mind paying a price for that at some stage in terms of upfront and annual costs. I accept moving away from fossil fuels will cost money. We are likely to make the switch once we downsize from our current home. 

I suspect not in my lifetime but the costs of renewable electricity may fall dramatically over time.

Switching some or all of the environmental costs from electricity to gas would help, but this would reduce the tax raised from running an electric car which is already too low. There is no easy way forward on the costs both upfront and ongoing. 

Posted by: @kev-m

@morgan, unless ASHP become 5 times as efficient as gas then it is going to be an uphill battle with that difference. I don't know if the next price cap change will alter it. 

Hi Everyone,

ASHP's can be 5 times more efficient than gas boilers, when they are operating at ambient air temperatures of +7C and above and water flow temperatures of 35C and below. The problem is that these operating conditions do not normally occur when the heat demand is at its greatest. The laws of thermodynamics limit what improvements can be made to the operation of the actual ASHP, so to improve efficiency requires adoption of different techniques and often additional equipment.

Adding a solar PV system to help power an ASHP is undoubtedly highly beneficial, and in the sunnier months can be used to provide hot water, and hence remove the need for an ASHP to operate at all.

Having a well designed and optimised control system can help ensure that an ASHP is operating in the most efficient manner.

Better insulation and larger heat emitters or UFH can all help to make the operation of an ASHP more efficient.

Using a solar thermal system, along with a heat store, could also help to make the operation of an ASHP more efficient.

Installing a GSHP rather than an ASHP would also improve efficiency.

Of course, all the above come with additional cost and quite often considerable disruption.

On the subject of fuel costs, for the foreseeable future electricity will always be more expensive than gas, whilst a large proportion is generated in gas fired power stations. Even when operating in combined cycle a gas fired power station is approximately 50% efficient. In open cycle this drops to around 35% efficiency. The cost of building a reasonable sized gas fired  power station is probably in the order of  1 to 2 billion pounds and then of course it has to be manned with highly trained staff to operate and maintain the plant. I don't know if it is still the same, but quite a few years ago when I was working at a gas fired power station, there was a charge of 6 million pounds each year for the grid connection, to allow the station to generate and export power. All of the above add to the cost of electricity produced.

Although I still have a gas boiler, which provides the majority of our heating during the colder months, I think that making gas 1/3 the cost of electricity would be much fairer and would help make ASHP's a much more viable alternative.

Posted by: @derek-m

Posted by: @kev-m

@morgan, unless ASHP become 5 times as efficient as gas then it is going to be an uphill battle with that difference. I don't know if the next price cap change will alter it. 

Hi Everyone,

ASHP's can be 5 times more efficient than gas boilers, when they are operating at ambient air temperatures of +7C and above and water flow temperatures of 35C and below. The problem is that these operating conditions do not normally occur when the heat demand is at its greatest. The laws of thermodynamics limit what improvements can be made to the operation of the actual ASHP, so to improve efficiency requires adoption of different techniques and often additional equipment.

 

Derek I hear what your saying but after looking at this for far too long now I just can't make the numbers add up. For instance maybe an ASHP can be 5 times as efficient but that is in the prime conditions and that would only be for a short time out of a whole year. Running at the low temp flows really does mean running it to Underfloor heating as the most effective way to heat with low heat source such as ASHP. then there's insulation and ensuring that your home is at its very best with regard to that. In my simplistic but I feel real world scenario is that ASHP's while an option are not a great option for the vast majority of UK households and the main reason is cost ! The cost of the ASHP in the first instance, the cost of matching it up with Underfloor heating (or at least suitable sized radiators so the ASHP isn't working to its extreme limits to provide heat) ensuring the house is as insulated as possible, offsetting some of the cost with installing a Solar PV to heat the hot water and provide electric to power the ASHP. As Mars pointed out there was some days that he was burning through tens of KW (up to 80 at one point) per day of electric and that is in a house with a mix of underfloor and radiators upstairs, now thats from someone that is spending a lot of time looking at every facet of the issues and trying to get the absolute best from the systems in place. I just can't see how the UK households are going to easily convert without out paying out tens of thousands of pounds per household and that in my view is the lowest cost I suspect if you add an ASHP, Solar PV, Underfloor heating, renewed Insulation and higher electric costs then its a minimum of 30k. Does their need to be a lot of gov incentives to make the country move to a non gas model, yes and if they don't people will start getting angry and begin to show their feelings when they have a choice of eating or heating their homes ! my money is on the government backing down first rather than the people !! just my two cents 

@boblochinver Hi Bob,

I agree with you totally. The point I was trying to make is that it is not just a case of installing an 'overpriced' heat pump or changing the tariffs for gas and electricity. I have just read an article on a financial website claiming that UK homes emit more CO2 than all the gas fired power stations, but it failed to state how much actually gas each is burning. If the homes are burning more gas than the power stations, then they will emit more CO2. In the same article it stated that a recent government energy efficiency scheme had collapsed after 6 months, with the National Audit Office blaming ministers for the 'botched' policy. Reducing energy consumption throughout the country is not simple and straightforward and requires a few 'adults' leading the way. I'm not holding my breath on that one.

@derek-m I used that scheme myself to get a heat pump. I personally had no issues. My dad also used it for some loft insulation. Not sure why it wasn't more widely take up to be honest

Posted by: @batalto

@derek-m I used that scheme myself to get a heat pump. I personally had no issues. My dad also used it for some loft insulation. Not sure why it wasn't more widely take up to be honest

Hi Batalto,

Probably because most people either didn't know about the scheme, or couldn't care less.

@boblochinver we shall see with my system. I was on Gas and swapped to ASHP. From my own calculations using SCOP of 2.8 I will be several hundred better off. But I was a heavy gas user for heating. Also our house is EPC "A" rated, so its very energy efficient in terms of insulation. However it will be very interesting to see how we perform across a whole year. Currently our bills are basically zero due to solar and battery

Symbio has now gone bust.  Should be interesting as they owe me over £300 from when I switched away from them last month.  Hopefully the new supplier will sort it out quicker than Symbio were (or weren't). 

Posted by: @kev-m

Symbio has now gone bust.  Should be interesting as they owe me over £300 from when I switched away from them last month.  Hopefully the new supplier will sort it out quicker than Symbio were (or weren't). 

So Kev, your the reason they went bust, demanding your £300 pounds back.