KWH used per year

ZZaffy

Just worked out my electricity usage for the year  from 01/04/22 to 30/03/23  is 3330KWH.
Is this an average or high amount for a small house?

Reed_Richards

To get a meaningful average you need to be more specific.  Do you use electricity for space heating or hot water (including electric showers)?

ZZaffy

I'll rewrite my question.  Used 3330kwh of electricity last year.  Is it worth having solar panels?

Reed_Richards

Again, we need more context.  Solar panels will most likely give you more electricity than you need in summer and less than you need in winter.  If you have an immersion heater and/or an electric vehicle either could use some of that spare summer electricity.  But if most of your electricity use is for heating in winter then solar panels won't have much impact.    

Reed_Richards

Lets put this another way:

When I moved in to my new house I was averaging about 8 kWh per day, which would have been 2920 kWh per year, not too far off your figure.  We used oil for both space and water heating but cooked electric.  Then, after 6 months, I got myself solar panels, 4.8 kWp of capacity and a 6.5 kWh battery.  This cut my electricity consumption to 1280 kWh in the next year.  So it looks as if I saved myself the cost of 1640 kWh of electricity.    

ZZaffy

Reed, thank you.  It is a complicated system. No gas here, so we have oil to heat the Aga downstairs and the radiators upstairs and the hot water tank. The kitchen is always warm from the Aga.  The wood burner in the lounge has an inadequate back boiler and is supposed to heat the radiators downstairs but doesn't.  However it heats the water.    The bathroom downstairs has a towel rail but the wood burner has to be roaring to get it to heat up and so we have had an electric element connected to it.   This is why I avoided your query first off.  
I thought the new solar panels worked in the winter as well as the summer because of photovoltaic cells, whatever they are.  

Reed_Richards

The reason you don't get much solar power in winter is the same reason it is cold in winter; the sun is low in the sky so the solar power heating the air and the ground you get from it is weaker.  And the days are shorter so you don't get the sun's power for as long.  This gives us colder weather and much less power from our solar panels.  Here is a chart of my generation versus date.   

[Deleted User]

ZZaffy said:

Reed, thank you.  It is a complicated system. No gas here, so we have oil to heat the Aga downstairs and the radiators upstairs and the hot water tank. The kitchen is always warm from the Aga.  The wood burner in the lounge has an inadequate back boiler and is supposed to heat the radiators downstairs but doesn't.  However it heats the water.    The bathroom downstairs has a towel rail but the wood burner has to be roaring to get it to heat up and so we have had an electric element connected to it.   This is why I avoided your query first off.  
I thought the new solar panels worked in the winter as well as the summer because of photovoltaic cells, whatever they are.  

Most PV solar array owners can only self-consume 25 to 50% of the generated electricity unless a battery is purchased. The reasons for this are clearly explained above.

For simplicity let’s assume that you have a 4kWp array of panels that generates 3900kWh/year. If you self-consumed 33%, then your Grid import would fall to about 2000kWh/year saving you 1333kWh of imported electricity at whatever tariff price you pay. The remaining 66% of solar output would go to the Grid generating up to 2600 x £0.15p/kWh of income. Add the Grid savings and income together and you can work out how long it would take you to pay off the installation cost of your new solar array.

the_lunatic_is_in_my_head

OP we have a similar set up to you, no oil but a wood burner with back boiler to the hot water & radiators with an immersion on the water for the summer months.

In the last 10 months we used 3189kWh of electric, during the winter that's about 250kWh per month, last spring it started off high at 450kWh per month but over the summer dropped down to 350kWh per month (probably due to being more careful with what we use) so it should average out at around 3500kWh or £1400 a year (at 36p per kWh).

I don't think the size of the house matters as we aren't heating with electric but we are using it for cooking where as you are presumably using the oil via the Aga so I guess our electricity overall should be higher.

You say your downstairs radiators don't heat up, do you have thermostats to control how much heat from the stove is sent to the hot water cylinder and the radiators? I can turn ours down so the pump kicks in sooner to send the hot water from the stove round the central heating meaning less heat goes to the water and more ends up in the rooms. It does take a lot of wood to heat the house and water this way, about a stacked cubic meter every two weeks but our house is large and difficult to heat. The fire doesn't really have to roar, it just needs a constant supply of fuel. 

Have you looked at evacuated tube solar for your hot water? If we had the money I think we'd go with this option to help heat the water in the summer months, it's not just the cost of the electric but having a more ready supply of water would be more comfortable as well. 

Reed_Richards

the_lunatic_is_in_my_head said:

Have you looked at evacuated tube solar for your hot water? 

There are two ways you can heat your hot water using solar power.  If your hot water tank has an immersion heater you can use the electricity from solar PV panels to power the immersion heater.  This is good because you should not need any modifications to your existing plumbing and the electricity from solar PVs can also be used to power anything electrical in your house or exported for an income for yourself.

Evacuated tube solar will require additional plumbing to interface with what you have already and can only be used for hot water so they are not much in favour at present.  The only advantage that I know of is that because they are tubes I believe they are less sensitive to the angle at which the sun hits them than a solar PV panel.   

Apodemus

ZZaffy said:

The wood burner in the lounge has an inadequate back boiler and is supposed to heat the radiators downstairs but doesn't.  However it heats the water.    The bathroom downstairs has a towel rail but the wood burner has to be roaring to get it to heat up and so we have had an electric element connected to it.   

Sounds as though that system could be made to work much more efficiently.  Is the hot water tank upstairs?  Depending on the arrangement you might have a pump, thermostat or possibly a zone valve problem.  Cost to sort this out should surely be much, much less than solar panels.