Solar Panels UK - is it worth it?

[Avendit]

I approached Puredrive on 18 November 2021 for further details, and as they never bothered to reply to my webform enquiry, I decided I would not bother with them.

so.energy saying they can do installs with them in ~3 months, they may have preferential supply over retail plebs.

 

[PITA]

Cheers for that. So.energy are saying that both 5 and 10kw are capped at 3kw discharge . Although reading the data sheet, I wonder what it means by rated output power 3000/5000VA?

Now just to decide whether to put a 10 panel NE facing set in or not :/ An extra 1700kwh/year generation for £2700, but it really alters the output curve to start generating much earlier in the AM.

3kW is ok though, if you're just wanting 'base load' cheap electric coverage... lights, washing machine, kettle, hair dryer type of thing.

Anything bigger like electric showers, heat pumps, cookers, car chargers, etc... will take all the 3kW plus Solar Generation, plus Grid Power to make up the difference.

If your Solar Array is generating 3kW on it's own... then you'll have 6kW combined discharge capability...

Going for the bigger Solar Array is worth it, in my opinion, just to boost your power all year round (if you can comfortably afford it)

Having access to Sunrise Solar power can be all you get some days, once the Clouds come over or weather changes. Can set you up for the day instead.

 

[roadcred]

Not Passivhause, no. We just got a bit lucky, and then I found a trick...

Our detached house was built in 1996, so it already had cavity wall insulation. So that's a good start.

Then about 10 years ago, I bought some big plastic Keter Storage sheds, and moved all the loft 'junk' into those. Then started buying offcuts of Natural Sheeps Wool loft insulation. Padding out the loft space once it was all empty. I now throw old duvets on top as well. They seem to work.

Then I replaced all the external doors with Secured by Design and 6mm laminate glass. Followed by all the windows with 28mm profile and 6mm laminate heat reflective glass, no trickle vents. This reduced noise, draughts & heat loss.

I paid special attention to gaps & draughts, so the fitters got a hard time to be very exact, filling & trimming etc.

I removed the Gas Fireplace and sealed up the flu, leaving a trickle vent at the bottom. We now have a large flatscreen where it used to be, seating is 6 meters away so it's a perfect location for that 'movie night' experience. I then removed the Gas Hob and replaced it with induction cooker.

Our Solar Array was oversized at 7.2kWp... so this was the 'trick'... as it bought us loads of EPC Points. Then I added an emersion heater & Eddi Solar Diverter to power it.

So now, we're pretty much all electric. But with a 'massive' (by their calculations) Solar Generator. This is how we blasted the EPC Rating.

He told me they cannot calculate the Tesla Powerwall Storage, as their system just cannot allow for it... but, he acknowledged it was perfect with Smart Meters for low cost energy.

Then through the post a few days later, he awarded us with a score of 107 (A+ Rated)... Carbon Negative.

Now the weird thing is, we'd scored so much on our Energy Generation, that removing our Gas Boiler was the only recommendation... to give us an extra 3 EPC Points.

So we decided against removing the Gas Boiler, and instead installed an Air to Air Heat Pump. This works independantly, so we can now choose between Gas or Electric heating... or BOTH at the same time. Ideal to mix and match pricing options.

The Gas Central heating is managed by NEST and Thermostatic Radiator Valves for zone control. The Heat Pump wall units are thermostatically controlled in each room, and provide Air Conditioning in Summer... so Solar drives that comfort.

I'm now looking into a Mechanical Ventilation & Heat Recovery system to finish off the air-flow quality, although I am monitoring & controlling humidity with Uhoo Air Monitors, SensorPush & Pro-Breeze. Dry air is easier to heat, and reduce airbourne viruses.

All our lights are LED, voice controlled and time scheduled. So each room power is turned off at night, so no 'standby' leakage.

The EPC now lasts 10 years, so I got a good head start on it all...

Your air to air heat pump is interesting. I have a largish detatched house with two gas boilers and u/f heating. My so9.96 solar array plus Poerwall 2, Eddi to the heating cylinders works very well in the summer months, but an air sorce heat pump could never replace my gas requirement in winter. I had not thought of using an air source heat pump to replace some of my winter gas requirements and work as coling in the summer.
What specifically is your electric heating system alternative and what sort of areas is it serving?

 

[PITA]

Your air to air heat pump is interesting. I have a largish detatched house with two gas boilers and u/f heating. My so9.96 solar array plus Poerwall 2, Eddi to the heating cylinders works very well in the summer months, but an air sorce heat pump could never replace my gas requirement in winter. I had not thought of using an air source heat pump to replace some of my winter gas requirements and work as coling in the summer.
What specifically is your electric heating system alternative and what sort of areas is it serving?

Yes exactly... good idea isn't it

We have a Toshiba Haori system (Air to Air Heat Pump)

1 x wall unit in Living Room
1 x wall unit in Master Bedroom
1 x wall unit in Office
1 x wall unit in South Facing kids room

So basically all the key living spaces.

Each internal wall unit delivers 2.5kW cooling and 3.5kW heating. But each unit can also be Power Modulated at 100%, 75% and 50% power. So Small rooms can be at 50% etc...

We use a single Compressor sited outside on a spare wall (very quiet) feeding all 4 internal units. It's called a split system, where all the internall wall units have to be in either Hot or Cold mode.

But you can have a seperate outdoor compressor for each unit, and independently control each one for hot or cold in each room, if you don't mind all that hardware outside.

Each internal wall unit is fed through pipework in the loft space. This means the internal wall units can be sited anywhere in the room (not just the external walls). The drain pipes go back up into the loft and each bedroom unit has it's own Peristaltic water pump in the loft space, which drains the water outside. Completely silent inside the bedrooms... it's very nice. Being able to site the wall units exactly where you want inside, means you can control where the heat/cooling is being delivered. We avoid directly overhead to stop 'cold drop'...

Our system can be in Heat Mode, Cooling Mode, Fan Mode or Dehumidifying Mode.

The internal wall units also filter PM2.5 particles with a Plasma Ionizer...

Fully voice controlled using Alexa, Smart Phone App control for scheduling & remote access and a nifty backlit hand controller.

My Wife absolutely loves Air Conditioning at home, the reason being, you can open all the Windows and enjoy the Summers Day... then when you've had enough and want a cool bedroom, you get a good nights sleep.

Plus if your Neighbour fires up the BBQ with smoke drifting your way... you can close all your Windows, slam on the Air Con and not overheat inside.

Like being on holiday, you can just cool down on your bed for a bit, then go back outside.

 

[roadcred]

Yes exactly... good idea isn't it

We have a Toshiba Haori system (Air to Air Heat Pump)

1 x wall unit in Living Room
1 x wall unit in Master Bedroom
1 x wall unit in Office
1 x wall unit in South Facing kids room

So basically all the key living spaces.

Each internal wall unit delivers 2.5kW cooling and 3.5kW heating. But each unit can also be Power Modulated at 100%, 75% and 50% power. So Small rooms can be at 50% etc...

We use a single Compressor sited outside on a spare wall (very quiet) feeding all 4 internal units. It's called a split system, where all the internall wall units have to be in either Hot or Cold mode.

But you can have a seperate outdoor compressor for each unit, and independently control each one for hot or cold in each room, if you don't mind all that hardware outside.

Each internal wall unit is fed through pipework in the loft space. This means the internal wall units can be sited anywhere in the room (not just the external walls). The drain pipes go back up into the loft and each bedroom unit has it's own Peristaltic water pump in the loft space, which drains the water outside. Completely silent inside the bedrooms... it's very nice. Being able to site the wall units exactly where you want inside, means you can control where the heat/cooling is being delivered. We avoid directly overhead to stop 'cold drop'...

Our system can be in Heat Mode, Cooling Mode, Fan Mode or Dehumidifying Mode.

The internal wall units also filter PM2.5 particles with a Plasma ironizer...

Fully voice controlled using Alexa, Smart Phone App control for scheduling & remote access and a nifty backlit hand controller.

My Wife absolutely loves Air Conditioning at home, the reason being, you can open all the Windows and enjoy the Summers Day... then when you've had enough and want a cool bedroom, you get a good nights sleep.

Plus if your Neighbour fires up the BBQ with smoke drifting your way... you can close all your Windows, slam on the Air Con and not overheat inside.

Like being on holiday, you can just cool down on your bed for a bit, then go back outside.

Thanks for that...indeed a brilliant idea! Great details thank you. However more info leads to further queries so if you dont mind
the rough cost of the installation?

rough floor area of rooms covered? I have 6 large rooms facing due South?

Was your designer/installer national or local?

 

[PDB33]

Yes exactly... good idea isn't it

We have a Toshiba Haori system (Air to Air Heat Pump)

1 x wall unit in Living Room
1 x wall unit in Master Bedroom
1 x wall unit in Office
1 x wall unit in South Facing kids room

So basically all the key living spaces.

Each internal wall unit delivers 2.5kW cooling and 3.5kW heating. But each unit can also be Power Modulated at 100%, 75% and 50% power. So Small rooms can be at 50% etc...

We use a single Compressor sited outside on a spare wall (very quiet) feeding all 4 internal units. It's called a split system, where all the internall wall units have to be in either Hot or Cold mode.

But you can have a seperate outdoor compressor for each unit, and independently control each one for hot or cold in each room, if you don't mind all that hardware outside.

Each internal wall unit is fed through pipework in the loft space. This means the internal wall units can be sited anywhere in the room (not just the external walls). The drain pipes go back up into the loft and each bedroom unit has it's own Peristaltic water pump in the loft space, which drains the water outside. Completely silent inside the bedrooms... it's very nice. Being able to site the wall units exactly where you want inside, means you can control where the heat/cooling is being delivered. We avoid directly overhead to stop 'cold drop'...

Our system can be in Heat Mode, Cooling Mode, Fan Mode or Dehumidifying Mode.

The internal wall units also filter PM2.5 particles with a Plasma Ionizer...

Fully voice controlled using Alexa, Smart Phone App control for scheduling & remote access and a nifty backlit hand controller.

My Wife absolutely loves Air Conditioning at home, the reason being, you can open all the Windows and enjoy the Summers Day... then when you've had enough and want a cool bedroom, you get a good nights sleep.

Plus if your Neighbour fires up the BBQ with smoke drifting your way... you can close all your Windows, slam on the Air Con and not overheat inside.

Like being on holiday, you can just cool down on your bed for a bit, then go back outside.

Completely agree about air-air HP. We installed a split system with wall units in main bedroom (2.5kW) and spare room (4.2kW – room is larger and always cold), initially with cooling in mind. They are great on the very few days when it’s uncomfortably hot at night, but are used mostly for heating. In winter, we leave the bedroom unheated at night and turn on the air-air a few minutes before getting up for shower and dressing, then turn off again. It warms the room in five minutes.

I would like to add it to the kitchen/dining area and the upstairs lounge, probably it would need another external unit. Does anyone have experience with floor standing indoor units (i.e. fixed at bottom of wall, like a conventional radiator) to avoid units higher on the wall?

 

[Avendit]

Do the air to air measure performance the same as air to water, ie COP?

 

[Lx2m3]

I’m a newby to solar and battery storage, just requesting some quotes for a PW and PVs.
This might seem like a daft question, but if I have 1 PW with a maximum continuous output of 5Kw and the demand goes over this, is the total energy supplied by the grid, or only the remainder?
Q2: Powerwall spec says charging or discharging is 5Kw, but I’ve seen mentioned a lower level for charging, is this just from PV?

 

[Dilly]

I’m a newby to solar and battery storage, just requesting some quotes for a PW and PVs.
This might seem like a daft question, but if I have 1 PW with a maximum continuous output of 5Kw and the demand goes over this, is the total energy supplied by the grid, or only the remainder?
Q2: Powerwall spec says charging or discharging is 5Kw, but I’ve seen mentioned a lower level for charging, is this just from PV?

Excess will come from the grid or solar. PW will do the 5kW
PW will charge from solar from 100 watts upward

 

[PITA]

Thanks for that...indeed a brilliant idea! Great details thank you. However more info leads to further queries so if you dont mind
the rough cost of the installation?

rough floor area of rooms covered? I have 6 large rooms facing due South?

Was your designer/installer national or local?

We're in an average 3 bedroom detached house and our full cost was £6,500 all in.

But... the guys we had we're totally not prepared for the job, as they were a Commercial Air Conditioning company and it showed. Lads were good, but supply delays turned a 3 day quoted install into 3 weeks with no regard for the disruption it caused.

So I wouldn't recommend them again for one instant. In fact I'm pretty confident they'll never do another Domestic installation again

But... the end result (eventually) is serving us very nicely, and I 100% recommend the proof of concept.

Your install costs will depend on way too many variables to even guess.

 

[Lx2m3]

Thanks Dilly,
Another question:
Do PV panels reduce in output efficiency over years? And is there any way a user can detect this reduction as sunlight is continually variable?

 

[PITA]

Completely agree about air-air HP. We installed a split system with wall units in main bedroom (2.5kW) and spare room (4.2kW – room is larger and always cold), initially with cooling in mind. They are great on the very few days when it’s uncomfortably hot at night, but are used mostly for heating. In winter, we leave the bedroom unheated at night and turn on the air-air a few minutes before getting up for shower and dressing, then turn off again. It warms the room in five minutes.

I would like to add it to the kitchen/dining area and the upstairs lounge, probably it would need another external unit. Does anyone have experience with floor standing indoor units (i.e. fixed at bottom of wall, like a conventional radiator) to avoid units higher on the wall?

Yeah, I used to use two floor standing units years ago, vented through a Window.

They work, but are very noisy... VERY noisy. As the compressor is inside the room as well.

They have to expel water into a trough, which needs emptying... or a hose for gravity feed.

But the unacceptable issue is in the design. As they vent out the hot air through a pipe... the unit has to draw replacement air back into the room... which is warm air... doh !!!

So they're noisy, inefficient and not maintenance free... but they can blow cold air onto you.

 

[PITA]

Do the air to air measure performance the same as air to water, ie COP?

Yes, I'm sure they do.

 

[PITA]

I’m a newby to solar and battery storage, just requesting some quotes for a PW and PVs.
This might seem like a daft question, but if I have 1 PW with a maximum continuous output of 5Kw and the demand goes over this, is the total energy supplied by the grid, or only the remainder?
Q2: Powerwall spec says charging or discharging is 5Kw, but I’ve seen mentioned a lower level for charging, is this just from PV?

Yes, as @Dilly said, the Powerwall will supply up to 5kW and then the remainder needed comes from Solar or Grid.

Grid charging speeds can be limited by your DNO or Tesla. Depending on what your cabling infrastructure can handle.

So yes... it may be limited.

My two Powerwalls were accidentally limited to 5kW charging by the installer... quick call to Tesla and they corrected the issue, inline with the DNO paperwork signoff.

So now we can charge & discharge at 10kW

 

[PITA]

Thanks Dilly,
Another question:
Do PV panels reduce in output efficiency over years? And is there any way a user can detect this reduction as sunlight is continually variable?

Yes they do degrade over decades... but it is slow.

We have a SolarEdge system with Sunpower Maxeon 3 panels with Power Optimizers.

In the Smartphone SolarEdge App, it shows every single panel... and its performance. So you can sort of compare each panel with it's neighbour.

If a panel stops working completely, or is severely reduced compared to it's neighbour panels... then you can raise a concern with your installers.

I don't know if every system is like this?

 

[RedMod3]

Our air-air system is similar to PITA's. We live in a 4-bed bungalow built in 1989 that used to have storage heaters, and we now have:

A 7.5kW Toshiba split outdoor unit with ceiling cassettes at the southern and middle end of our long hall with a quiet wall unit in the main bedroom which has IT that gets hot and needs cooling in summer.

A 5.0kW Toshiba split system with ceiling cassettes in northern end of our long hall with the other being in the lounge.

All other rooms have no heating/cooling units and rely on natural air-flow from our MVHR system.

The 5 units have individual Toshiba RB-RXS31-E remotes fixed to the walls near them, and they are coded A-B-A-B-A so the IR doesn't interfere; these are programmable.

One thing I learned is that to get effective heating in winter is not to leave them on AUTO, but to manually set the fan speed to one of the higher 5 settings.

These will be ideal for when our Powerwalls and extra PV get installed as the power consumption of our property is steady, we are now consuming 2.08kw while heating.

FYI, we moved from a smaller 4-bed house to this bungalow and I modelled the heating requirements by calculating the extra % heating needed using u values for all 6-sides of each room with known outdoor air temperature. U values are key.

Air to Air is the way to go IMHO.

 

[Dilly]

Thanks Dilly,
Another question:
Do PV panels reduce in output efficiency over years? And is there any way a user can detect this reduction as sunlight is continually variable?

@Lx2m3 I believe that like anything electrical, they and the inverters do lose efficiency Over time.
In summer, the panels and inverters slow down when they get hot. A really sunny day in May is more productive that an identical day in August.
my older panels are 6 years old and no drop off yet. I keep a daily record so I’d spot a drop in production. That’s the best way. Just read the meter daily. Sad really. I can look out of the window and know what the kWh value is I must get out more…

 

[RedMod3]

@Lx2m3 I believe that like anything electrical, they and the inverters do lose efficiency Over time.
In summer, the panels and inverters slow down when they get hot. A really sunny day in May is more productive that an identical day in August.
my older panels are 6 years old and no drop off yet. I keep a daily record so I’d spot a drop in production. That’s the best way. Just read the meter daily. Sad really. I can look out of the window and know what the kWh value is I must get out more…

I give my panels a wash with a hose/brush attachment once a year to reduce losses. The frame is connected to an earth rod, so I won't get a belt if the panels go live.

 

[RedMod3]

Just a thought, if there is a PEN fault, I reckon the Tesla Gateway will disconnect from the DNO Supply and go into back-up mode? Any thoughts?

 

[Mr H]

I'm not bothering with solar, i'll just wait for a power cut

Northern Powergrid sorry for Storm Arwen trillion pound compensation error

Customers hit by power cuts in Storm Arwen erroneously received cheques for trillions of pounds.

www.bbc.co.uk