underfloor heating question

daludo

hi folks,i have a 3 zone system at home,upstairs rads,downstairs u floor heating and then hot water.the 3 settings i have my timeclock set for the u floor are 12am-6.00am,9am-4pm and 8pm-12.is this too much??or not enough??we are spending 1900e a year to heat a2200sq foot house,is this normal??rads are on for 2 hrs in evening.hot water zone 3hrs a day.what do ye think??(by the way uf is zoned with room stats in each room)

TPM

It depends on alot of things. likr your insulation levels, the loop lengths, the pipe centers, the depth of the screed
I would leave all loops open and try something like
4am-6am
12pm-3pm
8pm-11pm

After that you can adjust the running time up or down according to the heat level in your house.
IMO you can only use timed heating or temperature control with underfloor heating not both, when you use both you can end up with a room not calling for heat when the heating is on only to look for heat when the boiler isnt on resulting in the floor temperature dropping low and requiring alot of heat to bring it back up.

freddyuk

The whole point of underfloor heating is to heat up a large mass ie. conrete and insulate underneath and around the edges so all the heat goes up into the room space. Getting that mass to temperature takes a lot of energy but once it is in there and once the room is up to desired temperature and if there are no massive heat losses due to drafty doors/wndows or poor insulation then all the boiler is doing is keeping that heat level topped up with occasional boosts of energy at very low water temperatures. You let it cool 4-5 degrees in the evening so it is cooler overnight and then early morning you boost it up to daytime requirement. Remember there is a time lag between switching on and actual benefit in room temperature.
Letting the whole mass cool down for a few hours with no heat input means the whole thing has to be re heated to get it to a useful temperature which makes no sense to me and is why the heating bill goes up. Get decent programmed room stats and let them run the system. Any residual heat will find its way upstairs so the rads, which run at much higher temperature will not need to heat so much. What do the under floor experts say?

daludo

thanks guys.il look into changing the analogue stats to programmable ones.might tinker around with leaving the uf on constant and just control by room stat,turn down hall and rooms we dnt use often etc.insulation/drafts is a prob i reckon too.