No br8ian. Its a big area so fundamentally it doesn't have to get that hot. Mine ran at round 25C in the open: bits covered in carpets/dogs/settees got up towards body heat. In fact the dogs learnt this...
Our supermarkets resemble the arctic IME!
The property has cavity wall insulation (installed just a few years ago) but the loft insulation isn't good. And below the T&G floorboards and laminate flooring there's a three foot void with the usual airbricks which must surely be a factor.
The renovation work includes a loft conversion, so better insulation will be incorporated there; and, whatever heating system I decide on, I plan to add insulation under the ground floor. New ground patio doors at the rear of the house will also presumably have better specs than the fifteen-year-old ones they're replacing.
The present heating arrangement (whatever its setting) can't combat a very cold zone by those rear patio doors. The new design will have such doors across almost the whole of the back of the building: if I go for a conventional system again I've been considering putting trench radiators along their length. Possibly UFH (together with increased insulation) would have the same effect, but there's no way of finding out until it's installed and if it doesn't work it'll be a bit late to change it.
Thanks to everyone for the thoughts and suggestions.
Have a look at the Speedfit videos. Rigid insulation should be laid supported by battens along the joists. Aluminium spreader plates are secured to the joist tops and the pipes run in pre-formed grooves. Not cheap and will still suffer from slow thermal response mentioned by others.
Wet underfloor heating best suits 24 hour occupation.
I work from home so I suppose I fit that category. During the day I leave the thermostat at around 20 degrees so the system doesn't kick in. If there's a sudden drop in the temperature outside (and hence inside) I adjust the thermostat upwards until the boiler fires.
I work from home so I suppose I fit that category, but given that I tend to use the thermostat more like a simple on/off switch, the rapid response time does seem to be central to want I need. Which does perhaps rule out UFH.
The underfloor heating in St Catherine's used to get quite uncomfortable after you had been sitting on it for half an hour.
*If and only if it's in-screed*
The OP mentions a suspended timber floor. If he lifts that, puts celotex between floor joists and lays pipes between, that's a very fast response UFH.
And will make the house a whole lot warmer anyway just from the insulation...
You only need rapid response because your house is poorly insulated
Houses do not 'suddenly drop in temperature when they are well insulated
In message , Bert Coules writes
It is normally controlled by local roomstats for each separate heated area. A large lounge might require 2 or more lengths of piping but controlled from one stat.
We have a modern annexe with underfloor wet heating in screed and find the temperature does not vary much from that set.
You can use weather compensation but I think overkill for a well insulated installation.
Mother in law had a flat in one of the London Barbican developments. That was underfloor electric which I found very uncomfortable. I'm not sure if they used the floor thermal mass and economy 7 or some other arrangement. It was not in the control of the occupier:-(
Tim Lamb wrote:.
Thanks for that. The overall footprint of the bungalow is a simple rectangle. The ground floor - currently the only floor - is completely open plan except for the bathroom, which cuts into one side of the space: broadly speaking the living area is in the shape of a very thick capital letter E with the central horizontal line missing. If it's practical, I suppose that could constitute two zones, one for the living area, another for the bathroom.
The new first floor will be essentially similar, so another two zones, perhaps.
What is the absolute minimum thickness required by UFH? As planned, the headroom on the new first floor is not generous: 2060mm on the drawings.
They do tend to have some areas which are dreadfully cold.
Many years ago, one of the supermarkets I used had a walk-through cool room section for dairy. Seemed quite a good idea but only seen it (so far as I remember) in two shops.
As the context is uk.d-i-y, and the topic was domestic underfloor heating, suddenly switching to large commercial premises was quite a jump. Still largely true - few supermarkets have good heating/cooling - tends to be too hot, too cold, too much draught, or too noisy. Even if it passed all those criteria, the stink from the bakery, pig cookery, chicken burner, etc., which will often fill the entire store, exemplifies why too much recycling of air round a building can be a bad idea.
From a similar era, our school library had electric underfloor heating. On some form of night tariff. Baking in the morning - windows wide open to let that excess heat out. Cool in the middle of the day. By end of afternoon, could be freezing.
Thickness of what?
As planned, the
I found that with UFH on ground floor, first floor without extra heating was a nice 3 degrees cooler.
20C ground in winter, 17C bedrooms..
Thickness of the whole installation. If the designed (bare chipboard) floor to ceiling height is 2060mm, how much will that be reduced by UFH?
Personally, I don't care to have a bedroom that's cooler than the rest of the house. I find that distinctly uncomfortable.
It can be very thin for the heating elements themselves:
or a bit thicker:
It all depends on how much insulation you have/want under the heating elements. I hadn't noticed you mention an upper floor before, just a single floor in a bungalow. Do you intend putting insulation under the tiles to keep the first floor warm?
FWIW, I have the first type of UFH (for laminate flooring) in a conservatory. It is on a screed floor over 50 mm Celotex and It can't keep the temperature at a comfortable level on a cold day less than 5 deg C outside or a not-so-cold day when it's windy,. So if needed, a fan heater has to be used as well. It is also bloody expensive to run.
Nor do I. But with an additional floor, much of your ground-floor heat will disappear upstairs unless there is a door between the ground and first floor. Any bedroom up there might well be warmer than the ground floor! With warm-air heating, it might be possible to recirculate the warm air which collects at the top of the building, so saving on heating and reducing temperature differences throughout the living areas. I don't know as I have not looked into that possibility. Don't "passive" houses use that sort of thing?
In message , Bert Coules writes
You can run the heating water through a towel rail. I'm told!
The laid over, pre-formed insulation is 25mm thick and is pre-grooved to take the pipe. Your flooring goes on top 18-22mm chip?
Otherwise, the fix from top system goes between the joists prior to laying the floor and does not raise the floor.
If you have just an inch of insulation underneath you will lose a LOT of heat downwards.
You MUST insulate under the floating floor with full 60-90mm of celotex
25 mm is fine for upstairs though
Underfloor heating with each room on it's own zone so each room has it's own programmable thermostat that you can set fallback (day/night un-occupied) temperature to depending on room usage. So office(?) set to
20 degrees and all others set to 18 degrees.Bedrooms on a 2nd circuit but radiators with TRV's rather than UFH So you have 2 system programmers or you could use a single programmer and use the H/W settings for bedrooms if you don't have H/W storage.
Our living rooms have very little thermal mass as the UFH is between floor joists with about 15cm of a sand/cement skim that I put in to provide a degree of heat spread also cheaper than aluminium spreader plates and I was concerned about spreader plates causing expansion/contraction noises at the time. Be aware you might need to re-run/re-wire at the same time as cables may be pulled through centre of joists which in my case was about an inch too high in some places.
It doesn't have a "rapid" response but now the house never cools down enough to cause a problem.
Having had no loft insulation for a few years after fitting UFH we had to have a halogen heater in the front room but after insulating I was able to drop the system temp to 50 degrees Max. and it's ample although because the boiler has weather compensation it's constantly changing flow temp based on outside temperature so a sudden drop in temperature can take the house around 36 hours to balance it's self again.
Beauty of weather compensation is the heating is never switched off. The boiler just won't run if the outside temp has reached a defined temperature e.g. 20 degrees and if it's say... 16 degrees the water might be circulating at less than 3 degrees which is perfect for both the UFH and the radiators.
Most important thing is having insulation up to spec. That way the heating will never need to heat from cold and you'll never need to worry about switching off the heating is you go away for a week. Or you could always lower the set-back temp to 16 degrees but for the few £ you'll save (if that) it's not worth it.
HTH Cheers - Pete
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