Ballpark expectations for energy consumption

patchyX2

I know the answer to this question is 'it depends', but any kind of rough idea would be helpful.

Let's assume that it's a 3 bed detached. Epc C. Good loft insulation, average wall insulation, modern doors/glazing, average energy use.

Now let's assume I were to splash out and buy the following:
- Heat pump. 
- Wet underfloor heating downstairs. 
- New rads and pipework upstairs. 
- Solar (10 east facing, 3 south facing, 3 west facing. No shade issues. South Coast of England). 
- Decent size of battery pack. 
- Water tank. 
- Tariff that allows selling excess energy and charging at off peak rates. 

After doing all this work, what would be a fair expectation for my energy bills? I imagine I'd be pretty much self sufficient during the summer months, but would be reliant on the grid during the winter. 

Over the course of the year, what sort of monthly energy bills would I be likely to see? Is there any chance could average ~£0? Sub £50? Sub £100?

As I said, I know the answer is 'it depends'. But any kind of rough idea would be good. Perhaps input from someone who has a similar setup?


**Edit** to clarify, the proposals above are for a house I'd be moving into, so I've got no idea what energy usage is/will be (comparing it to my current usage is therefore useless).

It will also be going through fairly extensive renovations, so it's not like I can move in and see what my new usage is either. 

BarelySentientAI

If you generate and sell more than you use by enough to offset the standing charge and the difference between import and export tariffs, less than zero.

If you don't, more than zero. 

Only you know what your consumption is, what the estimated output of the solar panels are, what temperature you like your rooms at....

NedS

You can use the online PVGIS system to give you an accurate estimate of any proposed solar production:

https://re.jrc.ec.europa.eu/pvg_tools/en/

The Gary does Solar Youtube channel also offers this calculator that will show you the effect of integrating a battery:

https://garydoessolar.com/utilities/dailymodellingutility/

If you know your current heat usage (kWh of gas), and can assume that will remain the same if switching to an ASHP, you can reduce your gas usage figure to 90% due to the inefficiency of a gas boiler, and then divide by 3 to give the kWh of electricity to provide the same heat output using an ASHP with a COP of 3 (300% efficient. It may be more efficient than that, but that's a reasonable assumption as a starting point).

patchyX2

Sorry, edited the OP to clarify I don't know what my usage will be, hence just looking for a rough idea. 

Reed_Richards

It's probably a mistake to design a heat pump system with a mixture of underfloor heating and radiators.  Unless the radiators are very very large they probably need the water to be hotter than the UFH requires.  If so, you don't get any economic benefit from having UFH; you might as well have all radiators.   

BarelySentientAI

PledgeX2 said:

Sorry, edited the OP to clarify I don't know what my usage will be, hence just looking for a rough idea. 

Then it's even less likely anything we can say will be useful.

Netexporter

Divide the heating and hot water load (from the EPC) by 3 to get the heat pump consumption. Divide the EV annual miles by 3 to get your charging consumption. Take away 1MWh per kW of solar.  Add 2000kWh for general consumption.

zxzxzx

@PledgeX2
I suggest you join the Givenergy forum and post the same question.
 The answers are likely to be similar to here, but there maybe someone with a set up that looks like your proposed house?

Alnat1

Not quite understanding why you're asking "how much per month" will I pay.

Get on a variable DD and you'll pay nothing at all from March because your credit from export will be building up in your energy account and be more than you are using. In winter you'll only have to start paying a DD once you've burned through the credit left over from the summer exports. 

It's possible, depending on tariffs/prices/usage, that you won't pay anything. You might have to make some payments Nov-Mar.