New House - New Heating System

GTunney_2

Hi everybody,

Been browsing these forums for quite some time now but thought i'd finally sign up.

I've recently bought my first house and looking to exchange and complete the end of August Woo Hoo!

The house currently has a solar system, conventional boiler and water harvester. I was wondering if anybody has had any experiences with a solar system and conventional boiler? I myself have always had combi boilers so used to having water as and when I need it so not used to this whole tank business.

Does anybody have an pro's and con's towards this type of system baring in mind I havn't paid a penny for the system so don't have to worry about any payback time.

Would really appreciate your thoughts and experiences with running the same or similar setup.

Thanks,
Greg

Cardew

Welcome to the forum.

This is presumably a solar thermal system(i.e. produces hot water) and not solar PV(produces electricity).

Assuming the former, and depending on the size/number of panels, it can produce a good deal of your hot water in the summer months, but precious little in the winter.

The Government commissioned a test of a number of systems some years ago, and on average they produced around 1,000kWh per year. So if you have gas, that is a saving of around £40 a year. Bear in mind there is a small cost for the electronics and pump that run on daytime electricity. The electronics are to 'sense' when there will be no net gain from the panels and turn off pump - otherwise the pump will send hot water from the tank up to the panels to cool down!!

Solar Thermal systems were often sold by unscrupulous salesmen who completely overstated the potential savings - several 'Watchdog' type programmes and a WHICH report on this aspect; plus the trading standards offices are full of complaints.

So in summary, useful to have, but don't expect huge savings!

GTunney_2

Hi Cardew,

Thanks for the reply.

Yes it is a thermal solar system, I suppose thats better then nothing as I didn't pay for the system. My partner tends to have several showers a day so in the summer hopefully it'll save us a bit of cash as our recent gas bill was over £100 for the past quater which I think is a lot.

I know this is a very stupid question as you know nothing about the type of system installed in the property apart from what i've told you but I don't suppose you'll know if the heating will also be fed off the tank or will this be supplied by the boiler? Like stated previously I'm so used to living in a combi world and don't want to go back to the old days of my sister using all the hot water (cold showers, bad childhood memory)

TIA
Greg

Cardew

Heating is not 'fed off tank' but comes direct from boiler.

The normal system is for the boiler to produce hot water at whatever (water) temperature you have set on the boiler.

This water goes to a diverter valve that directs the water to either:

A. radiators only

B. hot water tank only - to a coil inside the tank.

C. both hot water and radiators.

When the hot water tank is up to the required temperature(set by a thermostat on the tank in most cases) no more water from boiler enters the tank coil.

The solar panels feed a second coil in the hot water tank.

To a certain extent you might be going back to 'the bad old days' when you can run out of hot water. Most Hot Water tanks will have enough hot water for one good deep bath, but you might have to wait for the boiler to heat enough water for a second bath(make sure the boiler is switched on and to 'HW'). However modern gas boilers have a huge output and warm the water very quickly.

The big advantage over a combi is that you can get a a much faster flow of Hot water - better for showers and the bath fills quicker - - and running another tap has no effect like it does with a combi.

GTunney_2

I never have baths as I can't stand them plus no bath is big enough for me as i'm 6ft 5 lol.

I think once we're in the new house it'll just be showers for us and baths for the kids so hopefully there should be enough hot water there for the lot.

Thanks for all your help Cardew, you've helped me understand it all a bit better.

skintmumof2

My next door neighbours have solor panels that heat their hot water. (Original neighbours have moved now and we have new neighbours that have not a clue how to use them and we dont know either lol)
The original people that lived there had 2 babys (twins) and no end of animals lol and they used to say they always had hot water. In the winter they had a woodburner so hardly ever used their boiler.
So id guess you should be alright for water as you dont need the 'sun' really sunny to heat your water. They said it worked well on all the overcast days too.

RRatchet

Hi

We now have a large farmhouse heated by solar hot water panels/2 wood/coal burning appliances with back boilers & underfloor heating downstairs only and even this summer the panels produced enough hot water for at least 2 baths per day (most days) although not back to back you have to wait for a while before running the 2nd bath. We have 4 kids & don't bath/shower them or ourselves everyday, but sometimes there were events that meant 3 separate baths per day. We very occasionally put the stove on for room heating which also boosted the thermal store. For us this system works except just last week we noticed the solar system had sprung a small leak; which is probably why the pump has been running hot (maybe knackered - but hope not). Now that it's getting colder weather & less sun & dodgy pump we are running one stove from about 6pm until we go to bed. We chop our own wood well they say it heats you twice and the exercise doesn't go amiss. When it gets very cold we'll fire up the one stove for longer and when baltic we may have both stoves going. We are sort of at home all day (farming so outdoors a lot generating pour own heat) & so can give this system the attention it needs. A pal has a similar system to yours and reckons it has saved her money (no figures though to back it up but I do believe her).

It takes a while to learn how to react to/control? such a system. Yours sounds like it will be much easier as the conventional boiler will probably be able to be set to automatically top up the hot water stored in your tank the solar panels effectively acting as a pre heat
taking the edge of the cold water coming into it. As you say you 'didn't pay for it' and so don't have to make the same efficiency/cost effectiveness decisions as the person who installed it.

Cardew doesn't much rate solar hot water but he is 99.9% right on everything he posts and is very knowledgble on all things heating wise. Don't ask ne for the .1% he gets wrong cause I haven't conducted a full statistsical analy but no one gets it rught all the time.ysis of all his posts. You know what it's bloomin late, my typings gone to pot and I can't be botheres any more.

Enjoy your "free" soalr boost.

R

Cardew

RRatchet wrote: »

Hi
Cardew doesn't much rate solar hot water but he is 99.9% right on everything he posts and is very knowledgble on all things heating wise. Don't ask ne for the .1% he gets wrong cause I haven't conducted a full statistsical analy but no one gets it rught all the time.ysis of all his posts. You know what it's bloomin late, my typings gone to pot and I can't be botheres any more.

Enjoy your "free" soalr boost.

R

My 'rating' of solar thermal should be put in context.

The main objection is to the 'cowboys' who sell systems making outrageous claims, and charging equally outrageous prices. There have been countless complaints to trading standards offices and several 'Watchdog' type programmes on this subject.

The government commissioned tests of 10 solar thermal systems(both types) - that the solar industry(unsurprisingly) don't seem to publicise! The results gave an average output of about 1,000kWh a year(and this was in Southern England. savings of £40 pa or so if you have gas.

Even with that modest output, the vast majority was in the summer months and precious little in winter, plus the electricity to run the electronics and pump is at daytime electricity rates.

It simply didn't make financial sense to spend thousands of pounds to save tens of pounds.

Also everyone assumes that the system will run forever. It will be interesting to see how much your repair of a leak costs. Scaffolding(health and safety!!) etc - if on the roof you could be talking £hundreds.

Of course the new RHI proposals(if adopted) will add a whole new dimension. However the cowboys will be back to make another killing - watch prices increase.