Hi - help needed with PV - Heating - AC - Battery

[RonnyUK]

Hello - I am not native in English, so please forgive me for any grammatical or other errors

I am in the process of buying a house, 3 storey. currently a gas boiler for water and heating around 15 years old which is a guess for the lifespan of such. In the medium term, I plan to replace it.

I would now like to have a PV system installed on the house and the garage roof. What size do you generally recommend? Possible some more information would help?
The garage is a shared building, detached from the Main Building, i have sole access to the middle Garage from the rear.

Family of 4 (2 adults, 2 children) The car is currently a plug-in hybrid - in the long term it will probably be a BEV.

The garage is currently not connected to the mains electricity from the house. Cable needs to be laid down.

Also, I would like to have an AC for chilling at least floor 2 and 3 (bedrooms). The air conditioning should also be used for heating in the shoulder months, or at least reduce the load on the boiler ;-) (if thats possible) .

Although I grew up with solar thermal for hot water as a child, I understand from the first reading that you can probably heat the water cheaper with a PV and an immersion heater?

House and garage face south-east (~135 degrees)

How can I insert an image here?

looking forward to replies ;-).

 

[bladerunnerpv]

Hello RonnieUK, welcome to the forum.

Questions are probably best asked in the solar PV forum, you'll find lots of useful questions and answers there which will help you. Suggest you make a new thread there.

I'll do the easy bits here:

For Solar PV, there are some things you need to find out
i) How big is your roof? Think of it like a rectangle, what is the width and and the height? This is so you can work out how many solar panels will fit onto the roof. General recommendation on the forum is to install as much kWp per metre squared as possible!
ii) What is the tilt angle of the roof (and the garage) from the horizontal?
iii) How far is the garage from the house?
iv) You will get the most out of solar PV by adding some batteries so that you can store unused solar energy and use it later in the day
v) How much electricity do you use per year - family of four is commonly around 4000 kWh, with a battery you may get to about 50-70% of that from PV,
vi) Solar PV is unlikely to provide much energy in winter, take a look at "PVGIS", for example, to make some initial estimates of PV generation for your property.

It's probably wise to find out as much about the garage from the legal people whilst buying the house - is there anything legal which might prevent you from installing PV panels on the roof? (I have no idea if this is a real potential problem, I'm just guessing something similar to a party wall agreement may exist? I don't know the correct legal words) Also is it possible to lay a cable on your land directly between the house and the garage? A cable would not go across someone else's land?

 

[BorisJ]

Solar thermal is much more efficient for heating water than solar PV.

 

[RonnyUK]

Solar thermal is much more efficient for heating water than solar PV.

cost wise as well? installation cost of let`s say 4000£ vs savings annually of?

 

[johnb2713]

Solar thermal is much more efficient for heating water than solar PV.

It's not quite that clearcut.
If you want to run your tank at 85 deg C for example, you cant get there with Solar Thermal, you struggle to reach temperatures in the 60's. Solar Thermal is also nowhere near as flexible as solar PV and an immersion heater. Solar thermal is also more complex to install.

Apart from that, it's great

 

[Murdoch]

What is your current lecky consumption per year?

If your garage is some distance from the house and you want PV panels on both then best you get a local PV company round.

As for using surplus PV generated electricity to heat water - yes a good idea as the extra kit isn't too expensive but if you go for battery storage you may want to consider carefully how many days you will get any excess PV per year as it might be very few.

Make sure the installers don't use a circuit on a shared RCD too

 

[RonnyUK]

What is your current lecky consumption per year?

If your garage is some distance from the house and you want PV panels on both then best you get a local PV company round.

As for using surplus PV generated electricity to heat water - yes a good idea as the extra kit isn't too expensive but if you go for battery storage you may want to consider carefully how many days you will get any excess PV per year as it might be very few.

Make sure the installers don't use a circuit on a shared RCD too

sorry, what is RCD?

current consumption is not really helpful, as I am moving from a different house.

 

[RonnyUK]

Hello RonnieUK, welcome to the forum.

Questions are probably best asked in the solar PV forum, you'll find lots of useful questions and answers there which will help you. Suggest you make a new thread there.

I'll do the easy bits here:

For Solar PV, there are some things you need to find out
i) How big is your roof? Think of it like a rectangle, what is the width and and the height? This is so you can work out how many solar panels will fit onto the roof. General recommendation on the forum is to install as much kWp per metre squared as possible!
ii) What is the tilt angle of the roof (and the garage) from the horizontal?
iii) How far is the garage from the house?
iv) You will get the most out of solar PV by adding some batteries so that you can store unused solar energy and use it later in the day
v) How much electricity do you use per year - family of four is commonly around 4000 kWh, with a battery you may get to about 50-70% of that from PV,
vi) Solar PV is unlikely to provide much energy in winter, take a look at "PVGIS", for example, to make some initial estimates of PV generation for your property.

It's probably wise to find out as much about the garage from the legal people whilst buying the house - is there anything legal which might prevent you from installing PV panels on the roof? (I have no idea if this is a real potential problem, I'm just guessing something similar to a party wall agreement may exist? I don't know the correct legal words) Also is it possible to lay a cable on your land directly between the house and the garage? A cable would not go across someone else's land?

Hi Bladerunner,

it`s Ronny ;-)

1) good question regarding roof size, I cannot answer tbh.
2) house is around 45degree, garage more like 30degree i would think
3) let`s say around 25m walking distance via the garden
5) almost impossible to say I would think, as I am not living in the house yet, and the house I am currently living is is terribly insulated
6) what is PVGIS?

maybe the below will help understand with the garage? surrounded by red is the property I am buying.


Access to the garage is via the garden, there is a small alley for my sole use.

 

[bladerunnerpv]

Hi Bladerunner,

it`s Ronny ;-)

1) good question regarding roof size, I cannot answer tbh.
2) house is around 45degree, garage more like 30degree i would think
3) let`s say around 25m walking distance via the garden
5) almost impossible to say I would think, as I am not living in the house yet, and the house I am currently living is is terribly insulated
6) what is PVGIS?

(oops) Hi Ronny
1 perhaps work out from property details from estate agent. To start with assume 30deg roof pitch and do some trigonometry
6 free PV generation estimation tool

 

[Murdoch]

sorry, what is RCD?

current consumption is not really helpful, as I am moving from a different house.

RCD - Residual Current device

If both properties use gas heating, I suspect your consumption will not change much ...........

 

[RonnyUK]

RCD - Residual Current device

If both properties use gas heating, I suspect your consumption will not change much ...........

moving from a 2BR with bad insulation with to a well insulated 4BR townhouse - you might be right !

 

[Murdoch]

moving from a 2BR with bad insulation with to a well insulated 4BR townhouse - you might be right !

if you're not heating with electricity and the number of people remains the same then there should be very little change