Sorry yes KWH. I get 46.81p for each unit as a feed in tariff an extra 2p per KWH as I am with Utility Warehouse. Then I get an export tariff (50% is assumed to be used) of 3.3p from the company.
I generated 3700 kwh with an annual pay back of £1800ish plus export tariff of £63.
I used 5700 kwh of electric in the last 12 months at a cost of 13.25p each but my standing charge is only £2-90 a month this can make a big difference. With predicted annual cost of £832-25.
I used 7449 kwh of gas at 4.185 each and a standing charge of £1-40 a month. With predicted annual cost of £344.97.
I know my gas is low for a large house but I do have the best insulation and top of the range pressurised condensing system.....but it's still cheap but I won't complain.
My plan is to get a 4kw system and an immersion heater to utilise all the power. I also am at home most of the time so will use washer/drier etc when it's sunny and they are all efficient Miele appliances.
Is this what most people do?
Yes thats what I do but bear in mind the feed in tariff has gone down to something like 16p per unit so not as lucrative.
This, or working shifts and having time off during daylight hours at home is the key to benefiting from the free systems. IMO. If your house is empty from 8-4 Mon - Fri then there is only one real benificiary, and thats not you
If you get a system to run your immersion it would be pointless really running your appliances in the day.
The chances of you getting surplus energy on top of a 3kw immersion heater with a 4kw pv system is pretty slim.
I'm not sure how long it will take to heat up the water - but I can't imagine it taking more than a couple of hours.
Are you basing your calcs on a constant 3kw being diverted to your tank? It won't happen trust me. Well maybe once in a while but not very often.
Do you know how much electricity you use in standby? 4 - 500w I'd say is average. Don't forget to take this into account.
How big is your dhw tank? How much hot water do you use?
Without knowing these variables it's impossible to work out how long it will take to heat your tank but I'd say it's pretty reasonable to presume that you won't be satisfying your tank in 2 hours of sunlight.
I don't expect much during the winter months but want to use as much as possible. I will set the gas to come on at tea time to finish off the heating.
I am on smart meters so will be able to tell how much is being saved and the immersun shows on the display how much it has used.
I haven't had the smart meters/solar fitted yet but would expect it to heat the water in the summer months on a sunny day as the hot water isn't used during the day as all washer/dishwasher are cold fill.
How does the immersun record it's info to work out how much surplus you have at any one time? What can it tell you on its display?
Thanks.
It just has a small display - LCD display shows energy saved, output power and operating mode
It basically works out how much you're exporting and uses it all - it makes sure you export nothing or vey close. It also has relays so when the hot water is up to temp you can run something else off - say a storage heater.
http://www.immersun.co.uk