Anybody install UFH and oil fired boiler? Experience & running costs

Folks,

Would appreciate hearing from anybody who has installed UFH and using oil as the fuel source. I'm increasingly becoming sceptical about the payback on either pellet (given the cost of the boiler & ancillaries) or heat-pump technology & am wondering if its not better to focus on spending €€'s on insulation and opting for oil? About to commence building a 3400 dormer....UFH downstairs (2600 sq ft) and rads upstairs (800 sq ft). Thanks in advance, one confused apple!

Hi,
Going for same setup myself on 2200 sq.ft. bungalow. Also very sceptical on pellet and geothermal with huge initial costs (and other issues particularly for pellet, eg. storage, fuel supply, price uncertainty). Hoping to put in a good condensing oil burner/boiler, good insulation, and see how it goes. Making provision to add geothermal in the future (flow/return pipes from outside, blanked off initially).
Got a heating consultant to design system. He has recommended use of a buffer tank to reduce on/off cycling of oil burner and tells me should help with efficiency/economy. Buffer tank has 2 coils (one for solid-fuel stove and other for solar).

Thanks ennisjim. Would like to know a bit more about this idea of a buffer tank. What is it, what is its capacity, how is it integrated in the system & where typically is it physically? As a result of a combination of scepticism & tight financial situation, I'm leaning towards this type of system. Thanks, apple1.

Hi apple1.

Haven't got this system installed yet. It's all on paper at the moment. There are actually 2 tanks. The DHW cylinder has 2 coils - 1 comes from buffer tank and the other from solar panels. This is 300litre I think. Buffer tank is 500litre and also has 2 coils. One is fed from solid-fuel stove and other from solar. Oil boiler heats water in buffer tank directly (ie. same water in buffer tank as oil boiler. Buffer tank feeds UFH. Putting some rads in attic space in case develop in future. These are fed from buffer tank too.

The reason explained to me by heating consultant for solar going to both tanks is that solar will primarily heat DHW cylinder (Mar-Oct realistically) and during summer months it can also heat the buffer tank to some extent. This may help a little with space heating on those chilly summer evenings. To be honest I'm a little sceptical about this but the extra coil in the buffer tank and the extra motorised valve are not adding much cost so I'm prepared to go with his recommendation.

Putting in quite a high-spec UFH control system with each stat having wall stat and floor stat. Latter has 2 purposes (i) limit heat to floor to avoid damage to timber flooring (eg. overheat situations) and (ii) avoid drawing heat to UFH if wall stat detects coolness (eg. draught when window left open etc).

I have a bungalow but we have large amount of space available upstairs so tanks are going up there (over internal block walls for support) along with water tank, pumps, etc - he calls this the 'plant room' which makes it sound like we are building an office block

All sounds good on paper - however only time will tell if this is a good design Haven't costed it yet either but inclined to put the €'s into it to make it future proof (eg. buffer tank suitable for geo/heat pump in future if switch to that). Quite a lot of pumps in the design though so hope I'm not letting myself in for problems down the line if there are failures, etc.

Have a look at image at
[broken link removed]
which is quite close to the design we are going with. Main difference is in our case buffer tank (one on left) has 2 coils and we have stove driving additional coil.

Thanks again ennisjim. Appreciate the detailed response. Like the idea of incorporating the solar solution, but budget may not stretch. Its a choice for us between sunroom or natural slate + solar or vice-versa. Have any good brand condensing boilers been recommended to you yet?

Haven't looked at which brand condensing boiler to go for yet. Plumber suggests Grant but no more detail at the moment.
Re. solar - yes they're expensive. Installers are in my opinion gobbling up the SEI grant which is a pity. Hard to justify from payback point of view I think - I just like the idea of getting 'free' hot water for 6 months+ (not really free when I've forked out €5K+ for the system

apple1 said:

Its a choice for us between sunroom or natural slate + solar

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Hi apple1,

I would go with the sunroom if I were you! If it's positioned right you'll spent a lot of time in there - a nice warm, relaxing room to read the paper, have a glass of wine or even just to snooze in!

Spicey

I have UFH and oil boiler- details as follows

House: 2 storey 2900sq ft - UFH both levels

Boiler: Firebird 90/120 Riello Burner (83% eff.)

Total costs to date 1800 litres + electricity costs to run 3 pumps and 17 actuators

I'm glad I didn't go for the GSHP based on these costs. They are for heating the downstairs to 19 degrees and upstairs 18 degrees.

Thanks all for the feeback. While I recognise the attractiveness of the renewables element, I do think the payback on the initial investment for these newer technologies may not be that well calculated.

Ted....any harm to ask what these quantities equate to in terms of €€'s and how long you've been running the system? Also would really appreciate if you could recollet what the approximate initial outlay was?

Approx 1000 euro to date from October 2006. System installed last April. Costs: UFH 17 circuits over two floors - 2 pump stations and 2 manifolds and I think 12 stats - 10K and boiler 800 euro approx

Hi Ted. Just interested to know if you are using a buffer tank or if boiler is driving the UFH directly ?

Hi Ted,

Looking at putting in a similar system to yourself - the one niggle I've got is the cost od running UFH off an oil boiler. Would you have any up-to-date running costs now that you are approaching a year of usage?

Many thanks

when costing oil versus woodpellet you will have to factor in the cost of transferring to woodpellet (or similar) in the future..... because one of the very few guarantees we have is that oil prices will continue to rise.

personally, i dont think it makes any sense to run UFH from oil.
UFH does not have a high responsiveness factor, which is one the main pluses of an oil fired rad system..... so a gradual heating system works better... also an oil fired system burns at higher temps than a woodpellet system.... UFH works at lower temps than rad systems.... see my point?

i think a lot of people have put UFH systems into their new build without making allowances for it in the general construction...

How many have installed UFH yet still have passive vents in the walls???? a complete contradiction IMO.......
How many have done airtightness tests and got a value of less than 2??
How many UFH systems have been incorporated into 'direct labour' builds??

There has been a huge amount of money wasted in this country over the last 2-3 years by people trying to be energy conscious yet not understanding the basic principles....

sydthebeat said:

How many have installed UFH yet still have passive vents in the walls???? a complete contradiction IMO.......

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Just out of interest, what are the alternatives to passive vents (by which I assume you mean just knocking a hole in the wall)?

I can't believe that they use these in (say) Scandanavia or other cold climate countries: what do they use?

Sydthebeat,

I revisited wood pellet boilers recently again after being put off them initially by pellet supply problems etc. I still have strong concerns about the supply of pellets. While the grant for these systems is (or was!) generous, the cost of putting in appropriate storage/feeding systems is a cost that also needs to be factored in.
I ruled out Geo and Aerothermal systems because the economics dont add for me - grants recently halved too. From an environmental point of view, their ultimate dependence on oil to generate the electricity to run pumps/fans etc is still a problem. Either I burn the oil to heat my house or ESB burn the oil to provide the electricity to heat my house. To be honest I would be concerned about putting a system into my house that will use so much electricity that its only economical if I run it on Night Rate.
So given as you say that oil prices are only going to rise from here on in, my strategy is to use a good modulating condensing oil boiler (suitable for low temp systems like UFH from advice I have received) in my house initially with the intention of reassessing a move to WPB in the years to come when the lifetime of the oil boiler is nearing an end. Of course depending on what oil prices do, I have to accept that this decision could be forced on me sooner.

As a matter of interest - what's the issue with incorporating UFH into direct labour builds?

lfcjfc said:

As a matter of interest - what's the issue with incorporating UFH into direct labour builds?

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Syd can answer for himself too but from my experiences there are 2 reasons people go direct labour:

1. To save as much money as humanily possible i.e. UFH is viewed as an unnecessary expense
2. They are building with something pretty unusual that most contractors would have limited\no experience with and would run a mile from while they can find work in their comfort zone. i.e you have no alternative to direct labour where you have a better chance of conving individuals to work with you on something new.

Most direct labour builds fall into category 1 in my end of the country.

ang1170 said:

Just out of interest, what are the alternatives to passive vents (by which I assume you mean just knocking a hole in the wall)?

I can't believe that they use these in (say) Scandanavia or other cold climate countries: what do they use?

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i would always recommed that UFH should be installed hand-in-hand with a heat recover ventilation system (HRV)

lfcjfc said:

Sydthebeat,

I revisited wood pellet boilers recently again after being put off them initially by pellet supply problems etc. I still have strong concerns about the supply of pellets. While the grant for these systems is (or was!) generous, the cost of putting in appropriate storage/feeding systems is a cost that also needs to be factored in.

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This is a common issue from what im hearing, i can only go back to the point that oil is definately going to rise in price whereas wood pellets "should" become cheaper with mass production. Yes, i hear that the wood pellets in bags are costing as much as oil and delivery of pellets is approx half the cost..... this is something for the Minister of Environment to pump prime in the industry....

lfcjfc said:

I ruled out Geo and Aerothermal systems because the economics dont add for me - grants recently halved too. From an environmental point of view, their ultimate dependence on oil to generate the electricity to run pumps/fans etc is still a problem.

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You are completely correct with this statement, this is the main reason the grants have been halved and grants in other EU countries have been abolished for geothermal...

lfcjfc said:

my strategy is to use a good modulating condensing oil boiler (suitable for low temp systems like UFH from advice I have received) in my house initially with the intention of reassessing a move to WPB in the years to come when the lifetime of the oil boiler is nearing an end.

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that why i would advise to factor in the cost of converting down the line... it could be a false economy if you need to convert in the next 3-4 years...

lfcjfc said:

As a matter of interest - what's the issue with incorporating UFH into direct labour builds?

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My main problem with 'direct labour' builds differ from sas'. I see cases where clients choose to go down this route in order to budget for UFH and the like... this is completely wrong IMO.... in the vast majority of cases the clients have no or very little construction experience, they then think they can become project managers on a construction project??? They engage seperate groundswork, blocklayers, carpenters etc without any proper co-relation of these trades.... the client doesnt know by looking at a cill or jamb or head detail if its constructed correctly.. .they do not know what best practise is...... and more often than not they end up having to pay from their pockets to repair mistakes they did not forsee occuring.... the percieved savings can quite easily turn into unnecessary costs....

'Direct labour' IMHO is a complete disaster unless a competent, knowledgeable, full time project manager is appointed.....

while i understand sas' second point regarding challanging designs, i would also consider direct labour to be unsuitable for this situation, i would always recommend clients to go down the prefabrication route for unusual designs. mainly for the reasons as stated above.

I have ufh with an oil boiler installed 3 years ago it goes through appprox 2500-3000 ltrs of oil in an 1800 sq ft house / year, we are currently looking at changing to another heat source
Half the house is open plan so this is possibly why the cost is so high
also i think the regs for insulation back then were not as good as now,
and a lack of advice from our engineer to point out that even the reg's were too low,
I looked at the Wood pellet boilers and think the payback is to long for the more expensive ones, you still have the hassle of storing fuel and ordering it. I am now looking at a company "surface power" who do a solar heating package with an wind immersion back up, they say it can save 70 -90 % on your heating and h/w bills, you need no fuel storage and you dont need to ring up and order fuel,
Has any one had a system like this installed?
firstly i am going to increase the insulation level in the house
does anyone know if you can blow insulation into a 100mm cavity that already has 60mm of kingspan in it??
Personally i would not go for oil if i was building again, i would go for a more passive and better insulated house,
the underfloor heating is great though i could never do without it
Hope this helps

F.D said:

I have ufh with an oil boiler installed 3 years ago it goes through appprox 2500-3000 ltrs of oil in an 1800 sq ft house / year, we are currently looking at changing to another heat source
Half the house is open plan so this is possibly why the cost is so high
also i think the regs for insulation back then were not as good as now,
and a lack of advice from our engineer to point out that even the reg's were too low,
I looked at the Wood pellet boilers and think the payback is to long for the more expensive ones, you still have the hassle of storing fuel and ordering it. I am now looking at a company "surface power" who do a solar heating package with an wind immersion back up, they say it can save 70 -90 % on your heating and h/w bills, you need no fuel storage and you dont need to ring up and order fuel,
Has any one had a system like this installed?
firstly i am going to increase the insulation level in the house
does anyone know if you can blow insulation into a 100mm cavity that already has 60mm of kingspan in it??
Personally i would not go for oil if i was building again, i would go for a more passive and better insulated house,
the underfloor heating is great though i could never do without it
Hope this helps

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I would like to know more on the research you have done on the "surface pwoer" system you are thinking of going with. Who supplies it etc. I would also be keen to know if we can blow insulation into a cavity with insulation in it already. Opimistic

sydthebeat said:

i would always recommed that UFH should be installed hand-in-hand with a heat recover ventilation system (HRV)

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But what if this isn't suitable? I'm in the middle of adding an extension to a 100 year old house, and putting in UFH throughout (old and new).

It's not practical to add a HRV system. Are there any other alternatives for ventilation, other than knocking holes in the wall (which I can't believe they do in other countries)? Right now, ventilation is not a problem, as we have a howling gale coming up through the floorboards.....

Sorry for the slightly off-topic post, by the way...