SOLAR + OIL combo heating system -how much oil do you use in a year?

fressatty

just throwing this out there. I have 6m square THERMOMAX solar tube setup with a 500L tank -Space heating and DHW. Backup heating is supplied by 96% OFCH efficient condensing boiler. House is 3 bed bungalow, thoroughly insulated and approx 125m square floor space. I put 1000L in the tank in January and reckon i'll get another 2 months out of that before it needs a top up.

Anyone with a SOLAR + OFCH combo got info on their average OIL consumption?

is 1000L in a year good or bad?

glenkeo

Hi
1000l seems good.
I have 1000l water tank, with oil, 25kw back boiler stove. I have not hooked up solar yet, hope to do it in spring , the house is 280m2 will be in a year next month have gone through about 1000l oil and ½ tone coal (€140) and sticks in fire.
How did you find oil use over the summer, did the solar look after Heating and hot water, I never switched of the oil and only but fire on in evenings after work, and no fire from may until sept, quite happy with it so far has we have no electric showers and house is always same temp and 1 full of oil is not too bad.

fressatty

i'm happy with it. Despite the miserable summer I think i clocked well over 1200 solar water heating hours (according to the system) from February to present. Thats about 150 hours a month average (5 hours a day etc.) so that is usually enough to heat water up to 60 degrees without the need of a boiler backup to kick in. Even if the boiler does need to kick in, it will heat the water up to 60 degrees well within 15 or 20 minutes so it's not taking a lot of oil to do it because the solar may have got the water up to 40 or 50 before heavy clouds became an issue (it works through light cloud cover no probs).

On good days during the summer the system was shutting down due to over heating, i had to increase the water temp to 90 degrees to keep it running so to avoid overheating! I have Kingspan HP200's, 60 in total. I'd imagine you'd need similar or more.

It does what you would expect and surprisingly well too! It heats the water in the tank which is fed to your boiler which means the boiler works less in order to get the water up to right temp before circulating. I've only been looking into Oil usage and trying to compare systems without solar, i hope it's all been worth while because if i can get away with 1000L a year then i'll be happy!
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fressatty

Space heating is done via a Wood Pellet stove in the living room (this heats the whole house if i leave all doors open) so i really only use heating oil early in the morning and late evening before bed time.