Solar PV

[Click4B]

and cost to buy and install?

It is the cost to buy that is about the same as solar.

install as long as it’s mono block can be done as a diy install as it just hooks up to heating circuit in place of boiler.

 

[Click4B]

Here's an account of Alastair McIntosh's experience of solar & heat pump combination
http://www.alastairmcintosh.com/general/energy/solar-heating.htm

Will have a read, this was my original plan, heat pump then add solar later on.

as long as I’m living in the house it’s fine, we will leave it running all day off the thermostat so it just keeps house a constant temperature... like we do now with nest, it sits on 23 and just tops up the heat throughout the day.

problem is, if we rent this house out later on... tenant might start turning heating off when they go to work, so house gets cold through the day... then they come home 8 hours later and switch it back on expecting house to warm up in a short period of time like a gas boiler... and when it doesn’t and takes significantly longer due to the lower heat output they might start kicking up about how it don’t work properly.

plus I’d imagine they are expensive to repair and parts aren’t readily available.

so that made me doubt the option of heat pump... but ironically it’s my favoured method due to running costs being similar to gas.

then stick solar on it and electricity bills stay low with it costing next to nothing to heat the house.

 

[JohnD]

Do you mean £6k for the solar and £6k for the pump?

 

[bsr]

Last year my unshaded South facing 4.5kw system generated 4200kwh so perhaps you could expect 9mwh over the year.

Have you seen iboost and zappi? They are a much cheaper way of getting solar energy into your hot water.

What heat emitters will you use? Heat pumps will work much better with underfloor than with radiators.

I don't think your worry about tenant complaints is a real issue. The tenant just needs to be told that the heating is very efficient but has to be left on 24/7.

Have you looked into hybrid boilers? My company is trialing some. They are an air source heat pump backed up by a gas boiler.

 

[Click4B]

Do you mean £6k for the solar and £6k for the pump?

wont be exactly £6k for each.

but material cost isn’t far off give or take.

just over 10kw worth of panels, 8kw inverter comes to a few £ over £5000, then add all the isolators, fixing kit for the roof, cabling and other misc parts and £6k probably isn’t too far off.

then look at a 9kw split heatpump with an internal and external unit, that’s £3k for an old model therma V from LG.

then to get best for hot water need to throw in a specific unvented cylinder with larger coil for heat pump due to lower temp, that’s around another £1000 so that’s £4K.

then all the pipework, electrical cable, isolators and misc components add another £1k like the solar panels. That’s now up to £5k. So about £1000 difference five or take as a conservative estimate.

 

[Click4B]

Last year my unshaded South facing 4.5kw system generated 4200kwh so perhaps you could expect 9mwh over the year.

Have you seen iboost and zappi? They are a much cheaper way of getting solar energy into your hot water.

What heat emitters will you use? Heat pumps will work much better with underfloor than with radiators.

I don't think your worry about tenant complaints is a real issue. The tenant just needs to be told that the heating is very efficient but has to be left on 24/7.

Have you looked into hybrid boilers? My company is trialing some. They are an air source heat pump backed up by a gas boiler.

will be underfloor heating regardless of which heating method, I don’t think Heatpumps work particularly well on rads, need to start oversizing them and considering aluminium rads. But never going to be same as the heat distribution from underfloor and it’s a smaller emitter surface area.

difficulty I have comparing the solar figures is when you look at installs on an east facing roof, you look at their energy generation in the colder months and it may well generate 3-4kw if lucky at peak and you see it start off around 7am in the morning; gradually ramp up.... then it peaks, hits midday and predictably as sun heads to the west side of the roof,.. energy production starts dropping back off again like dropping off a Cliff.

so you end up only producing for half a day and that ends up as very little.

but not so many people that have displayed their energy generation information online have a 50:50 split east west.

so 5kw per side.

and at least theoretically that alone could double daily energy production because it would ramp up from 7-8am in the morning, peak around midday but instead of dropping straight off a cliff it would hold it for a bit longer and carry on generating until late afternoon and gradually ramp down as the sun sets.

obviously south facing roof doesn’t have this problem so much but as mine is east west I need east west to compare.

i can’t comment on tenant issue as I don’t know, but I’ve seen some on some groups for tenants and landlords who just switch everything off before they head out because they worry about using electric while they are out and want to keep their bills down.