Best time to heat DHW with ASHP

[PhilT]

1 hour ago, AliG said:

I have consistently argued that people should not make PV investment decisions based on recent inflated electricity prices.

Absolutely right to be cautious about this, same for batteries, however some say the outlook for energy prices to be at least double the 5 year pre 2021 average until 2030

https://www.cornwall-insight.com/press/energy-prices-to-remain-significantly-above-average-up-to-2030-and-beyond/

[dpmiller]

47 minutes ago, JohnMo said:

Just had a look on money saving expert and they did a writeup on the benefits or otherwise of E7. Unless you are using a min 40% of your all electric on cheap rate, you are loosing money by having E7.

 

https://www.moneysavingexpert.com/utilities/economy-7/

 

Depends on the standing charge surely?

[SteamyTea]

45 minutes ago, JohnMo said:

Just had a look on money saving expert and they did a writeup on the benefits or otherwise of E7. Unless you are using a min 40% of your all electric on cheap rate, you are loosing money by having E7.

 

https://www.moneysavingexpert.com/utilities/economy-7/

My usage is usually over 80%. Harder to do in summer as the usually day usage, around 1 kWh stays the same  but the night usage goes down from around 10 to 14 kWh to around 2 to 3 kWh.

[JohnMo]

1 hour ago, dpmiller said:

 

Depends on the standing charge surely?

Why? Standing charge is small compared to usage. It's the price difference between day and night and standing charges on E7 and that compared to standard rate electric with its standing charge.

[SteamyTea]

22 minutes ago, JohnMo said:

Why? Standing charge is small compared to usage. It's the price difference between day and night and standing charges on E7 and that compared to standard rate electric with its standing charge.

At around 60p a day, part of which is to bail out people that don't pay their bills, I think it is expensive.

Yesterday I used 4 kWh, 3 at night, so 45p for that, 50p for the day unit, and 60p for the privilege.

£1.55, a third is the rental. 

[TonyT]

I would get a cheap night time tariff and run the hot water during this window.

[dpmiller]

34 minutes ago, SteamyTea said:

At around 60p a day, part of which is to bail out people that don't pay their bills, I think it is expensive.

Yesterday I used 4 kWh, 3 at night, so 45p for that, 50p for the day unit, and 60p for the privilege.

£1.55, a third is the rental. 

11p/ day here.

[SteamyTea]

1 hour ago, dpmiller said:

11p/ day here.

How do you heat hot water?

[dpmiller]

1 hour ago, SteamyTea said:

How do you heat hot water?

depends. ASHP tops the tank up- and catches better half's morning shower- during the E7 period in winter. Currently the PV is diverting to it.

[SteamyTea]

I would think if I had PV there would currently be days when I literally import nothing at the moment.

[sharpener]

1 hour ago, SteamyTea said:

I would think if I had PV there would currently be days when I literally import nothing at the moment.

 

[Johnbhoy80]

Is it best to heat the DHW on economical mode (No immersion and set to 48 but probably rarely gets above 43) with a timer set for 1 to 2 hours overnight on E7 or am I better to heat on standard DHW mode? (And does that require the immersion to be on?)

[JohnMo]

I am just running mine to heat between 6am and 7.30am (E7) to 50 degs, normally takes 45 mins, purely from the heat pump, no immersion.  Keeps us in hot water all day. No need to do legionella at that temp either, so immersion only runs if we have excess solar, not likely to happen for awhile though.

[Johnbhoy80]

Hi JohnMo, thanks for the response.  I think I will try to run my system on eco with no immersion and a 2 hour timer with DHW set to 50.