wet underfloor heating with baxi combi 105 HE

19 Mar 2009
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United Kingdom

Im thinking of installing wet underfloor heating to an extension which will be around 35sqm.

I have a newish Baxi combi 105 HE boiler, will this boiler be beefy enough to run the UFH & my other rads & hot water?


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I would think boiler will manage that little task
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The boiler is not the problem!

The question is if you understand the controlability issues with UFH !

Next its if there will be enough heat output. UFH has a maximum output of about 50-60 W per m² and thats not always enough on its own so may need a rad as well!

The main issue is the running cost is likely to be much higher if you only need heating for a short time.

If you are retired or work from home and will have the heating on all the day then its fine. But you cannot just put it on for 30 minutes because it takes two hours to heat up and some time to cool down ( wasting heat ). In that case it gives great comfort and is much the same cost as other heating.


thanks for the info, there will be someone at home, mainly the wife with 3 kids to look after.

I was thinking of going for electric UFH but ive heard the running costs of electric is more, then again ive heard that gas prices are on the up.

Do you have UFH ? If so what do you have?
You multiply the floor area by the output per m² I did it and got 1.75 kW.

I dont work in BTU as they our outdated since before I was born but think there is about 3412 BTU in a kW or so.

UFH is fine in libraries and old peoples homes but as it is unsuitable for efficient timed use then I would not want it where I live as I like to keep costs to a minimum.

It does not respond to changes in temperatures either!

Bedrooms are a particular problem! You want it warm when you go to bed but then want it cool a few minutes later to go to sleep. You only get that when you open a window.

Conventional warms up in 15 minutes which is what I like.


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