PV to replace solar hot water panels

[Marvin]

After much deliberation I am removing the solar hot water panels from the roof and replacing the area with PV. 

 

I have heard others say on Buildhub that the solar hot water idea is dead and I tend to agree as we have an ASHP.

 

Also it reduces the amount of systems in the house to be maintained.

 

 

 

 

 

[Bramco]

I wish PV had been cheaper before we installed solar thermal (our PV came a few years after the s thermal) - I'd have done the whole roof in solar PV rather than half solar thermal and half PV.   With PV divert and more than one immersion you can get a tankful of hot water with a much simpler installation.

 

It's also a bit of a nightmare when it comes to selling. Our current house will go on the market next month as we hope to be in the new build early next year.  

 

You should see the looks our heat bank gets from some of the locals who know we'll be selling who have asked for a preview.  I can see most prospective buyers thinking - you know what I'll save the space, put in a combi and I'll be fine.   Of course they'll lose the mains pressure how water, the fact that we get as much in FiT payments as we are charged for gas and electricity....

 

Simon

[Nickfromwales]

KISS is the way forward   Electricity is abundantly more useful than an ever hot DHW cylinder all summer. 

[Marvin]

Yes our solar HW was years before PV and I kind of got the habit. However now installed ASHP it's a completely different situation.

[Bramco]

3 minutes ago, Marvin said:

However now installed ASHP it's a completely different situation.

Yep, new house will be ASHP, Solar PV with divert to 2 immersions. Much simpler.

 

Simon

[Fly100]

Our Solar diverts any spare power to the Immersion. We rarely have the boiler on from April until October for DHW. seems a no brainer to me.

[ProDave]

What nobody has mentioned is you need a bigger area of solar PV to give the same output as solar thermal.

[SteamyTea]

11 minutes ago, ProDave said:

What nobody has mentioned is you need a bigger area of solar PV to give the same output as solar thermal.

But PV can produce effective power for a greater part of the year, and in lower light levels.

[ProDave]

2 minutes ago, SteamyTea said:

But PV can produce effective power for a greater part of the year, and in lower light levels.

Nobody is disputing that.  All I am saying is don't just replace your (probably) 2 solar thermal panels with 2 similar sized solar PV panels and expect as much hot water from them.  You will need more of your roof covered in solar PV.

 

Personally if I had solar thermal and it worked I would keep it and add solar PV as well.

[Onoff]

On 29/08/2021 at 14:26, Marvin said:

After much deliberation I am removing the solar hot water panels from the roof and replacing the area with PV. 

 

I have heard others say on Buildhub that the solar hot water idea is dead and I tend to agree as we have an ASHP.

 

Also it reduces the amount of systems in the house to be maintained.

 

 

 

 

 

 

Ahem...I tend to visit the IoW once a year and have a roof rack...what's the plan for the ST panels once removed? ?

 

Could bring my lad and maybe finally get him a flight with Butterfly Dave!

[Gone West]

The house I recently moved into has a 4kWp PV system and a 1.4kWp ST system. I wouldn't remove the ST system because it works well and I may get an EV which would soak up excess generation. Adding PV may involve changing the inverter, losing FiT payments and going above the G83/G98 limit.

[Marvin]

1 hour ago, ProDave said:

What nobody has mentioned is you need a bigger area of solar PV to give the same output as solar thermal.

Very true. The only thing is I had 4 times the heat in the summer when I didn't need very hot water, where as I can use the PV to produce cooling, and not enough heat in the winter when I need hotter water.

 

Also it's another system to maintain.

[Marvin]

40 minutes ago, Onoff said:

 

Ahem...I tend to visit the IoW once a year and have a roof rack...what's the plan for the ST panels once removed? ?

 

Could bring my lad and maybe finally get him a flight with Butterfly Dave!

There yours if we can sort out some time in the not too distant future.  ?

[Marvin]

Solar panels down in one piece.

 

Working on Mvhr coil design 

Edited September 6, 2021 by Marvin
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