Solar PV - [not] Great Expectations!

[Ollyfp]

I've just had a basic 2.5kw solar PV system installed with no battery. It's up and running and looks impressive enough, but how much can I (realistically) expect to save on my electric bill each month? Typically, I'm paying £60 including my standing charge during the summer months, so I'm thinking that WHEN the sun shines, my fridge and washing machine might just about be running on 'free' electricity, which I'm guessing might save about £5 a month?
Does anyone run a similar system?
Personally, I've always been a solar sceptic, but when my wife gets an idea... well, you know.

 

[JohnD]

It will make useful amounts in the summer months. Mine face due South and generate between about 9.30am and 4pm.

Without getting obsessive, use your tumbledrier and immersion heater between those times. It will cut the cost of air conditioning on sunny days.

If you have a gas boiler, the cost of summer gas for HW is so low that there is no profit on buying an Immersun or similar.

Generation in winter is negligible.

If you have an electric car, charge it during the day.

 

[Brigadier]

I've just had a basic 2.5kw solar PV system installed with no battery. It's up and running and looks impressive enough, but how much can I (realistically) expect to save on my electric bill each month? Typically, I'm paying £60 including my standing charge during the summer months, so I'm thinking that WHEN the sun shines, my fridge and washing machine might just about be running on 'free' electricity, which I'm guessing might save about £5 a month?
Does anyone run a similar system?
Personally, I've always been a solar sceptic, but when my wife gets an idea... well, you know.

I've just had a (functioning) monitor display for my utility use.

Even at full chat, my A-rated washing machine uses less than 2.5kw and, even then, only for fleeting parts of the cycle.

A full cycle (2.5 hrs, 60 degrees) cost under 40p, at 36p/kwH.

That's the sort of scale of cost I've seen, so work from there.

As regards an EV, it'll be far cheaper to charge at night on an economy 7 - type tariff.
At 7 kwH charge rate, my night tariff of 6p/kwH costs 42p/hr.
During the day, that goes up to c. £2.50/hr.
Even if saving a third of that for full - sun replenishment, night charging is loads cheaper.


Long and the short of it then, unless I was running a commercial boil wash laundry, the costs aren't going to concern me.

 

[Ollyfp]

That's good to know! With no gas in our area, we're committed to having an ASHP system fitted very soon. We've been relying on our old immersion heater since decommissioning the old oil boiler in January due to a final (and terminal) malfunction.
We put a one-touch plug-in 15 min interval timer on the immersion heater and it's actually been very cheap to use. Hmmm... Lol

 

[Ollyfp]

Maybe I can buy solar panels for my 2005 Ranger! Lol

 

[motorbiking]

Without a battery they don’t make much sense as a 2.5kw system isn’t really going to produce enough power at the right time to make a difference. In the peak months you might generate 12-15kw most of which will be exported.

Any reason you didn’t opt for a battery?

If you have an EV, you are still better off charging on a night tariff than charging during the day with probably 1kw out of 7kw coming from your panels.

 

[JohnD]

Even at full chat, my A-rated washing machine uses less than 2.5kw and, even then, only for fleeting parts of the cycle.

My washing machine, and my dishwasher, and my ovens, only use significant electricity when heating from cold, which takes around ten minutes. If it's sunny, the panels cover it.

The dishwasher heats again for final rinse, and the oven ticks on and off according to the thermostat.

The motors and pumps are not significant.

Only the tumbledrier heats continously. So when possible, I run it during daylight. The panels cover other usage during daylight, except in heavy cloud.

I have a friend who heats his home office with electric radiators during the day using solar.

 

[Ollyfp]

Without a battery they don’t make much sense as a 2.5kw system isn’t really going to produce enough power at the right time to make a difference. In the peak months you might generate 12-15kw most of which will be exported.

Any reason you didn’t opt for a battery?

If you have an EV, you are still better off charging on a night tariff than charging during the day with probably 1kw out of 7kw coming from your panels.

I'm semi-retired, so I'll be heating the house during the day, but we're happy at 18°, which should be achievable with the ASHP. As the fully South facing PV panels will be supplimenting the mains, I'm hoping the running costs won't be too eye-watering. I opted not to have the battery purely due to budgetary restrictions.
Oh, and EVs aren't the thing to have out here in the sticks! My old Ranger has saved the day on many occasions!
Thanks for your input and advice!

 

[fourtytwo]

I would have my old oil boiler back in a flash! No ripoff standing charges, buy energy when the price is right, what's not to like (sadly I moved house & left it behind).
I would be very very wary of ASHP, is your house exceptionally well insulated ?
Are you intending to have new radiators and pipework ?
Are you aware you will probably still need the immersion for proper hot water ?
Have you got a clear idea how much heat it will produce on a cold frosty morning and how much time it will spend defrosting ?

In your situation I would just buy a new oil boiler.

 

[Ollyfp]

I would have my old oil boiler back in a flash! No ripoff standing charges, buy energy when the price is right, what's not to like (sadly I moved house & left it behind).
I would be very very wary of ASHP, is your house exceptionally well insulated ?
Are you intending to have new radiators and pipework ?
Are you aware you will probably still need the immersion for proper hot water ?
Have you got a clear idea how much heat it will produce on a cold frosty morning and how much time it will spend defrosting ?

In your situation I would just buy a new oil boiler.

Thanks! And those were my thoughts a year ago, but having given the matter a great deal of thought, I changed my mind, based on the fact that we are very well insulated and the entire oil system needed replacing. It was over 40 years old. Time will tell if I've made the right decision. I think it boils down to whether your heating system works with your particular lifestyle. I'll keep you posted!

 

[diy_fun_uk]

How much did it cost to install?

 

[Murdochcat]

We have a 4kw system and it’s reduced our electricity consumption by about 40%

To get the most out of your solar you need to change your habits and run your washing, dish washer and tumble dryer during the day

Slow cookers help too

Do you have a hot water tank ? If you do you should seriously consider getting a divertor to send all excess energy to your hot tank - free hot water all year and you will be surprised sun you get during the winter


Ps - we’ve not had the best summer and that affects the output a lot

 

[Ollyfp]

How much did it cost to install?

We were quoted circa £8k plus rads for the complete new oil boiler system, and with the grant available to us (because we're in an area where there is no gas) the installation costs are comparable.
The oil boiler did used to burn hot and it worked well, but I never really liked that faint oil smell hanging around, so that's a little plus for me personally. The smell doesn't bother my neighbours, but maybe they're just used to it.

 

[Ollyfp]

We have a 4kw system and it’s reduced our electricity consumption by about 40%

To get the most out of your solar you need to change your habits and run your washing, dish washer and tumble dryer during the day

Slow cookers help too

Do you have a hot water tank ? If you do you should seriously consider getting a divertor to send all excess energy to your hot tank - free hot water all year and you will be surprised sun you get during the winter


Ps - we’ve not had the best summer and that affects the output a lot

Great advice! Thanks!

 

[Harry Bloomfield]

If you have an EV, you are still better off charging on a night tariff than charging during the day with probably 1kw out of 7kw coming from your panels.

Some systems, can be set to only draw the power, created by solar for charging during the day. Alternately, the solar output could be setup to heat the immersion heater. Batteries are expensive to buy, expensive to replace.