Crazy heating costs

short_frank

I have a new build bungalow with Underfloor heating fitted. I have all the nescesarry insulation above, below and in the walls but I am using ( and have been since start up) about €200 every 3 weeks. My underfloor heating installer is blaming my boiler (a Firebird outdoor one) but then he would blame the one thing he didn't install. I paid €300 for new digital room thermostats and streched it from the original €200 in two weeks to as it is now. I am running around 19 degrees and it is comfortable.
Any help would be GRATEFULLY recieved.

Reyman

Something seriously wrong. I have an old bungalow with no insulation with gas fired radiator heating and I'm spending max €100 a month in mid winter.

Though I don't heat the bedrooms in the day time. That could make a difference

noby

I'd get on to the supplier of the boiler. Or get someone out to look at it/service it.

prospect

Frank,

I am in a similar situation. Our UFH installation was a disaster.

1. We discovered that the thermostats were mixed up. So our living room stat was controling the actuator for the bedroom, etc. etc.

2. We had to replace the boiler with a higher rated one, and increase its nozzle size. Theory, get the water (and then floor) up to temperature as quick as possible, and then maintain that temperature.

3. The stat that controled the circulation pump was set too low. This meant that when the boiler was off, the pump kept circulating the water (which is now cold) around the system, and this was actually cooling the floor down again!!! (This should be set to about 38oC AFAIR)

4. The timing was all wrong on ours. As it stands the boiler is set to 50oC, and it comes on at the following intervals:
- 6am to 9am
- 11am to 1pm
- 3pm to 5pm
- 7pm to 10pm

5. Do not allow the floor cool down. If you turn off the heating for a few days, it takes up far more energy to get the floor back to temperature. You should heat it, and themn nmaintain that temperature.

Hope this helps. We were burning 1000L a month, and I will let you know how this months consumption goes after all these changes have come into effect.

P

lomb

UFH is a very inefficient way of heating a house theoretically. itdoes look modern though.

aniascor

I lived in an apartment which had underfloor heating a couple of years ago. Our bills used to be around €400-500 every two months (the whole thing was run off ESB). No matter what we did, we couldn't reduce the bill amount, and I don't think we are usually that heavy on electricity.

I now live in an apartment with storage heating instead, and even though there are four of us in this apartment (there were just two in the other apartment), the bills are less than €200 every two months...and this is a bigger apartment.

I'm betting it is the underfloor heating that is pushing your costs up (although I have no technical expertise to justify this opinion, only personal experience).

yop

We have our UFH on both floors and it is running 8 hours a day at this stage, coming in about 15 euros per week. We are running off Geothermal.
What spacing is between the UFH pipes do you know, this has a lot to do with it, if the spacing is too wide then you are talking about less coverage of the room, therefore you are needing a higher circulating temp to achieve your thermostats temp.

Also try to keep your thermostats to a similar temp, ideally between 19 & 20 degrees C. As regards the inefficency, your rads run at about 60 degree C, if your UFH is done right it will run at 35 degress C, I would be interested to see how UFH can be seen as inefficent?

patrido

frank, prospect,
What UFH systems do you have? Was it installed by the supplier or by a specialised installer or a non specialised plumber?

I'm doing some work at the moment on development of UFH systems, and as part of that I'm researching why some people's UFH operates very well, while others costs them a fortune. I'm really interested in hearing/seeing some of the horror stories that are all too frequent. I need to identify how these problems occur and how they can be solved without major expense.

I can take a look at your system and attempt to work out what the problems are. I'm not selling anything, and I won't charge for it. There are several possible problems, some that are easily fixed.

Your boiler might be a problem (though not the first place I'd look), but it's more likely that it is cycling too much. Boilers run very efficiently when doing a long burn, and inefficiently when a low amount of heat is required. UFH in certain situations can cause the boiler to cycle. This is neither a flaw in the boiler nor UFH - it's a flaw in the design of the overall heating system. The UFH market is not very well developed in Ireland yet, and installers tend to look at it in isolation from the other components of the system.

Ideally the whole space heating and DHW systems should be designed in consulatation with the architect at a very early stage. Your UFH installer's "that's not my area" attitude stinks.

PM me is you're interested please

patrido

short_frank

It was installed by a specialist installer (who I won't name, libel laws and all that, but I wouldn't reccomend him to anyone). My knowledge of the system and the most efficiant way to run it has all been learnt from the internet or talking to others as my installers young surly worker commissioned the system he just walked out without any explanation of the system and I only managed to get him on the phone by threatening him with a solictor.
The boiler doesn't run for long bursts. The boiler is set at 75 degrees and the thing that seems most unusual to me is that no matter what time of day or night I have a full water tank of boiling hot water (40 gallon tank) which the system seems to draw from before it turns on the boiler. To my untrained mind the theory of the system seems to be good and I have been in houses that swear by the system but I really don't know what has gone wrong with mine. I live in Mayo Patrido and if you are willing to travel there you are welcome to look at the system.

yop

Short Frank - I think I might guess who you are on about who has a burst of useless young lads working for him, a load of vans by any chance?

Is 75 degrees not very high to have the boiler at by any chance? Would 60 degrees not give you plenty of heat and hot water?

Viking House

What kind of walls do you have in your house?

short_frank

Standard 4 inch cavity block with kingspan insulation.
I now have a broken circulating pump. I got a plumber friend of mine round and he said there was no air relief valve (that may be the wrong name but it was to allow any air in the system to bleed off before it reached the pump) and the pump air locked and ran dry. I am now at the hair pulling out position (if I had any to pull).

Viking House

Maybe the insulation in the walls is not tight up against the inner wall and you are getting Thermal Looping. This reduces the effect of the cavity insulation by 50% - 75%.
To avoid this, the gap between the insulation and the wall can't be more than 1.5mm at any one point in your walls.
This is really difficult to achieve.