Here are our average consumptions when it's -4C, 0-3C, 4-7c and over 8C outside running on weather compensation.

In the next video we'll compare our running costs to oil boilers because we have that data. I have no idea how to get a get comparison to gas though. Any suggestions anyone how I can draw a comparison? 

@editor

It is claimed that a condensing gas boiler should be in the region of 90% efficient, so dividing your Energy Out figure by 0.9 should provide the number of kWh of gas that would be required. For the cost you would need to know the tariff.

@editor do you know your heat loss for your home? its size in m2? the heat outputs that your system is generating for these inputs? presumably because you have a 18kw heat pump you have a substantial property so the heat loss has to be larger due to its size? resulting in consumption numbers that are quite high  , but perhaps reasonable per m2 of property size ?

what I'm trying to say: if you present these to "mr average size house" they might look rather large!

doing the maths 90kwh for your -4C day could be £25- £30 on a standard variable tariff. 

vs Gas : if your HP's COP on that day was 2.5 , then you'd need (90*2.5 / 0.9) = 250kwh of gas  for the same heat. cost @ 7p / kwH= £17

We’re busting the biggest heat pump myths in this episode of Homeowners’ Q&A, and we’ve got experts Leah Robson (Your Energy Your Way), Derrick Denton (UK Alternative Energy) and Mark Denman (Custom Renewables) on hand to set the record straight!

@editor One myth that featured in this presentation is a real disgrace (and yes, we all know it exists but shouldn’t be given the breath of life at all); it was mentioned at the end and relates to the ignorance/fear of builders who should know better. So when asked about a heat pump, not only don’t recommend one but will try to dissuade potential customers from even considering one! They don’t work, nah, don’t have one of those things, don’t waste your money, you’ll never be warm etc. etc. etc. I have been spun this line by several gas boiler fitters and I would dearly like to get them to visit now and experience how well they can work if fitted properly!

One politician exclaimed ‘Education, Education, Education, well, he can blair it out but would people listen? I’ve joined Visita Heatpump and look forward to boring the rear end off anyone who visits and will listen. Regards, Toodles.

@editor I guess the DWH strategy used can be influenced by the tariff one is on.

For example I have a 200 litre DHW tank with an Octopus Go tariff. Heating the tank to 55C, yes the COP is worse and the water needs blending but heating the tank at 3am only costs 16 - 20p a day. A full tank usually lasts us all day.

If I heated the tank to 44C the system would end up doing at least 2 DHW cycles at an approx cost of 40p per day because one cycle would be during daytime rate electricity.

If I had a single rate electricity tariff then the 44C strategy would then be the better approach.

You have to look at your situation, do the math and not necessarily aim for the best COP for all situations as it can sometimes work against you from a cost point of view 🙂

@technogeek valid point about overheating on a cheap tariff. We still don’t have a smart meter, but that’s a great strategy. It just shows each home in terms of usage, requirements and consumption is different.

@editor Hence the wide range of tariffs? Toodles.

@editor If I was in your shoes I would be making fitting a smart meter a priority. I know they have had bad press recently but smart meters open up a whole new world!

We are lucky enough in Cambridgeshire to have Octopus PowerUps and I frequently overdrive the heat pump to warm the house, switch the tank immersion on, washing, charge car if the Wife is at home etc. Enough in the Winter to earn on average £40 - £80 a month back on my bill.

The only tech I wished I had was batteries, you can get paid for charging them and then save even more money when using the energy at another time

If you are on Agile you can take advantage of price plunges etc, a whole new world I say!

I think the point was well made by @leah-robson in the video about other related technology. Heat pumps work perfectly well in their own right as replacements for gas or oil boilers, but the fact they are electrically powered means any time you combine them with other domestic renewable energy systems you are able to ratchet up the benefits markedly. Solar PV, wind turbines, domestic batteries, time of use tariffs, all play a part.

Eventually, I think we've all been somewhat conditioned into compartmentalised problem solving when looking at domestic bills:

• Heating bill too high? Replace old inefficient boiler with a new efficient one.
• Car running costs too high? Change for a smaller/more efficient car.
• Cost of cooking too high? Get an airfryer/pressure cooker/slow cooker.
• Electricity bills too high? Look around for a cheaper tariff and/or try to use less leccy.

I'm not going to suggest that any of those possibilities is necessarily a bad idea, but let's face it; the financial end goal is for us to minimise our overall cost of living whilst doing as much of what we want to do as possible. Buying an electric car means your leccy bill will go through the roof but if what you save in petrol or diesel is even greater then what does it matter? As a result, I'm firmly convinced we should maintain a focus on the overall cost of running the household and only make changes affecting individual bits where we can see what part they play in the grander scheme.

Yes, heat pumps' running costs are (installed and designed well) quite possibly going to save a little on the running costs. However, the fact they run on an energy source you can generate and store domestically means there's a huge amount more flexibility into how they can be run and therefore how much the household's overall running costs can be reduced.

@technogeek I feel that the solar PV pays for investing in the summer as the reduced production in the months where the heat pump is required will contribute but unlikely to cover the costs - the summer’s production investment goes a long way towards it though. As to the battery situation, yes, very good plan and Octopus also have the saving sessions where lowering consumption or even ‘going negative’ and sending solar/battery output to the grid can be lucrative. Last winter, there were some sessions paying as much as £4.50 per kWh saved / exported. They certainly help; my bill was reduced by some £400 in all. Rewards, Toodles.

Posted by: @technogeek

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If I was in your shoes I would be making fitting a smart meter a priority. I know they have had bad press recently but smart meters open up a whole new world!

We want to fit one, but the location in our kitchen is awful and it would involve some rather invasive work to access the meter. So it remains on the back burner for now.