Hot water heating- What are my options??

Dante79

Hi,
I am planning to install solar panels/tubes next spring for hot water heating to reduce my dependence on oil. I am wondering should i go ahead with the solar or are there any alternatives worth considering? I built my house two years ago, i have good orientation for solar, i already have a stove with back boiler and an oil boiler. I also have a tripe coil cylinder installed.

My budget is around €2500, is solar my best option for this budget? I would like to hear from anyone who has experience of any alternatives. Thanks

MicktheMan

Dante79 wrote: »

Hi,
I am planning to install solar panels/tubes next spring for hot water heating to reduce my dependence on oil. I am wondering should i go ahead with the solar or are there any alternatives worth considering? I built my house two years ago, i have good orientation for solar, i already have a stove with back boiler and an oil boiler. I also have a tripe coil cylinder installed.

My budget is around €2500, is solar my best option for this budget? I would like to hear from anyone who has experience of any alternatives. Thanks

Any client that asks me something like the above is always asked the following:
How much do you actually spend now on heating hot water?
Generally the answer is "I have no idea but the salesman said blah blah".

Critically look at what you already have (stove, oil boiler, cylinder etc) and investigate if this can be optimised before wasting spending your money on eco bling.

BryanF

MicktheMan wrote: »

Any client that asks me something like the above is always asked the following:
How much do you actually spend now on heating hot water?
Generally the answer is "I have no idea but the salesman said blah blah".

Critically look at what you already have (stove, oil boiler, cylinder etc) and investigate if this can be optimised before wasting spending your money on eco bling.

your very negative on the aul solar panels there Mick:)
is 'ecobling' really how you see them?

MicktheMan

BryanF wrote: »

is 'ecobling' really how you see them?

In a lot of cases, yes (especially wrt how solar thermal is sold in this country).

In general, a lot of people don't really understand how they heat their water. All they know is if they flick that switch or turn that knob or light the stove then they get hot water.

Without first exploring how to optimise what they already have for generating hot water, getting solar installed is like buying an electric car to do the short trips to the shops in the summer while having a perfectly good conventional car in the driveway.

Dante79

Ok, so at the moment i am spending €1400 per year on oil for central heating and hot water. How much of this €1400 is actually spent on heating water is hard to calculate. The hot water is on every morning for 1 hour, this usually provides enough hot water for the day.
Thankfully my family supply me with turf so have no outlay fueling the stove. So my total heating bill is €1400.
I have a condensing boiler, Stratford stove and insulated triple coil cylinder, controlled with a System link HomeZone.

So would it be even cost effective to get 'ecobling' Solar or any other water heating system for that matter? If i install solar, how much would i be likely be saving a year? How long before i would see a return on my investment? My idea was not to be dependent on oil in the future, as prices are only going one way.

MicktheMan

OP, you heat your water similar to me. My hot water zone is timed to come on for an hour every morning and this does the hw needs for the day (3 teenage daughters in house). I have measured this consumption and it costs me approx. 300 euro per year.

Of the 1400, suppose your hot water costs you 400 in oil. Solar may give you all your hw needs for 6 months saving you 200. At 2500 investment, this give a 12 year payback. (Note; inflation etc not taken into account).
There may be ways of getting a better payback on the investment by, for example, reducing the space heating need (improving airtightness / insulation).

soundskin

I'd agree with Mick.

10-20% of that €1,400 will go on hot water. Therefore the majority of your bill goes to heating your house. It's much harder to heat a house of circa 1,800 sq ft than say 150L hot water cylinder.

Solar will cover 70% of your domestic hot water load. If you do the calculations then payback with be a very long time. However saying that, it will pay for itself, it's then free hot water and you are doing your bit for the carbon footprint.

You also have to account for service work, replacing antifreeze after 5 years and purging the system etc.

If it was me, then i'm get the best of what i have, try insulate the house better and reduce my heating load, that is where the majority of money goes and therefor will be saved in the long run.

saibhne

MicktheMan wrote: »

(Note; inflation etc not taken into account).
.

This is incredibly important, the payback calculation absolutely needs to take into account inflation etc.. particularly if you are on carbon intensive fuels. Oil, gas and electricity have all doubled in price the last ten years, that's about a 7 -8% annual increase. Some increase, even basic inflation at 1- 2%, has to be factored in to give an accurate cost projection. Making a decision on a simple payback calculation is unlikely to give you a true picture.

By applying this calculation two things change, the payback time drops obviously but importantly the running costs of an existing system on oil, gas or electricity increase exponentially as 7% is added on every year. The big question to ask is whether what happened to prices over the last ten years will continue at the same rate - my guess is yes.

See the EU statistics site for historical energy prices in Ireland and the EU. Link below and graphs for Irish gas and electricity prices attached. Oil prices can be seen here: http://www.cheapestoil.ie/articles/trend.aspx but I can't vouch for the info, seems consistent with other prices though.

http://epp.eurostat.ec.europa.eu/portal/page/portal/energy/data/main_tables

MicktheMan

saibhne wrote: »

This is incredibly important, the payback calculation absolutely needs to take into account inflation etc.. particularly if you are on carbon intensive fuels. Oil, gas and electricity have all doubled in price the last ten years, that's about a 7 -8% annual increase. Some increase, even basic inflation at 1- 2%, has to be factored in to give an accurate cost projection. Making a decision on a simple payback calculation is unlikely to give you a true picture.

By applying this calculation two things change, the payback time drops obviously but importantly the running costs of an existing system on oil, gas or electricity increase exponentially as 7% is added on every year. The big question to ask is whether what happened to prices over the last ten years will continue at the same rate - my guess is yes.

See the EU statistics site for historical energy prices in Ireland and the EU. Link below and graphs for Irish gas and electricity prices attached. Oil prices can be seen here: http://www.cheapestoil.ie/articles/trend.aspx but I can't vouch for the info, seems consistent with other prices though.

http://epp.eurostat.ec.europa.eu/portal/page/portal/energy/data/main_tables

You are correct of course but my point to the OP was that such as small fraction of the carbon intensive fuel used goes to heating water. The majority of it goes on space heating and if this element could be reduced then the payback would be better and the OP would be more comfortable.

saibhne

MicktheMan wrote: »

You are correct of course but my point to the OP was that such as small fraction of the carbon intensive fuel used goes to heating water. The majority of it goes on space heating and if this element could be reduced then the payback would be better and the OP would be more comfortable.

The OPs house was built 2 years ago so his insulation levels are likely to be high assuming building regulations were met, his oil boiler would be new and of high efficiency so there is unlikely to be any easy savings to be made there and it sounds like a heating control system is in place. Once a house is well insulated the proportion of energy dedicated to heating water increases and is probably 30% or more of their spend - Solar is a good option for the OP particularly because he wants to get away from oil. However the impression given was that a solar thermal system will pay for itself in 12 years but it will be better than that if you account for price increases. More like 8 years..

MicktheMan

saibhne wrote: »

The OPs house was built 2 years ago so his insulation levels are likely to be high assuming building regulations were met, his oil boiler would be new and of high efficiency so there is unlikely to be any easy savings to be made there and it sounds like a heating control system is in place. Once a house is well insulated the proportion of energy dedicated to heating water increases and is probably 30% or more of their spend - Solar is a good option for the OP particularly because he wants to get away from oil.

However the impression given was that a solar thermal system will pay for itself in 12 years but it will be better than that if you account for price increases. More like 8 years..

A 2 year old house insulated and built according to the building regs may not be as good as you outline above for various reasons and, unfortunately, I come across this daily.
For this reason I advise clients to first monitor/measure how much actual oil they use to heat their water before deciding to go solar as the results may indicate that the money may be better spent in the long run on improving the heat retention properties (and thereby comfort) of the house. If the house fabric is optimised for heat retention (not just insulation but airtightness & ventilation too), then by all means go for solar. Of course, the next question is what type (thermal or PV) but that's another storey:)

So, to reiterate, imo anyone thinking of going solar thermal should do their own homework and not rely on the salesman's "expertise".