Underfloor heating - thinking of getting UFH in ground floor with concrete floors

Browneyedgirl4

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Thinking of getting UFH in ground floor as part of a retrofit of a 1970s house (gas boiler). The downstairs floors are concrete and I don’t want the hassle of digging them up to insulate them. Did anyone do this recently and how was it done ? Was it worth the hassle and is the house much warmer ?
 

newirishman

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If you are planning to put in UFH, I strongly recommend to dig up the concrete and floor and insulate properly.
Everything else is a waste of money.
 

Baby boomer

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Don't know about retrofitting but we got UFH and heat pump with a new build. Very comfortable, very pleased with it. Gives a very constant all day heat but that also depends on having good insulation. Apart from the heating side of things a huge advantage is that the lack of radiators gives far more flexibility when laying out a room. Go for it, I'd say.
 

ashambles

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I think you're going to have to completely dig the floors up anyway to put the new UFH piping down into a new screed. I don't see how you can avoid it, unless you're happy to raise your floor level by several centimeters.
 

noproblem

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Thinking of getting UFH in ground floor as part of a retrofit of a 1970s house (gas boiler). The downstairs floors are concrete and I don’t want the hassle of digging them up to insulate them. Did anyone do this recently and how was it done ? Was it worth the hassle and is the house much warmer ?
Serious work involved and would imagine in the present times high cost also. If you're thinking of doing this, you'll have to take up all the floors and do serious insulation too. If it's part of a retro-fit and grants involved you'll need to get all the rest done too if it hasn't already been done. By that I mean cavity wall insulation, attic insulation up to at least 300mm, windows, doors, possible roof panels, new cylinder and making sure you get a draught survey done too. You may need to change your upstairs rads to ensure efficiency along with considering a heat pump as well. There are companies out there who will give you a proper quotation for all this. You won't get the survey/quotation for nothing, but if you go ahead and do it they'll take the survey cost off.
 

Leo

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UFH driven by a gas boiler without digging up floors just isn't practical, you would have to lay insulation, pipes, and then a screed over all that to a depth of a few inches. Even without insulation, you're adding 1+ inches to the floor level and you'd lose a lot of heat to the ground. Either way you will have all the disruption of adjsting doors, architraves, skirting, built-in furniture, bathroom fittings, etc., etc..

You could install electic UFH with a lower thickness, but that would be horrendously expensive to run.
 

Alkers86

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Thinking of getting UFH in ground floor as part of a retrofit of a 1970s house (gas boiler). The downstairs floors are concrete and I don’t want the hassle of digging them up to insulate them. Did anyone do this recently and how was it done ? Was it worth the hassle and is the house much warmer ?
Total non runner. UFH shouldn't feel any warmer than radiators with a correctly setup time and thermostat control.

Are you planning to stick with a gas boiler or get a heat pump?
 

bstop

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354
With radiators you have a rapid response heating system. With underfloor heating you have a slow response system, slow to heat up and slow to cool down, it is basically a large storage heater. Ireland’s climate is more suited to a rapid response system.
In the winter when you get sunshine for a few hours often this is enough to heat a house. You can turn off the radiators if the solar heating is sufficient and they cool rapidly. If you have underfloor heating the house will probably overheat.
On a chilly summer evening you can turn on radiators for a short period and get quick heating. This would be impracticable with under floor heating.
 

Leo

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Ireland’s climate is more suited to a rapid response system.
Slow versus rapid response system choice is more down to occupancy patterns and insulation levels. Slow response works perfectly well in our temperate climate as we experience much less significant temperature swings than many other regions.
 

Buddyboy

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We have both. UFH in the living room, where we......live. All day comfort also with programmable stats.
Radiators in the bedrooms and bathrooms where we have rapid heating for 1st thing in the morning when we get up, and last thing at night when we go to bed, all rads with TRVs.

Best of both worlds.
 

bstop

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354
Slow versus rapid response system choice is more down to occupancy patterns and insulation levels. Slow response works perfectly well in our temperate climate as we experience much less significant temperature swings than many other regions.
Ireland is at a very high latitude. This results in massive winter solar gain in any rooms with southerly facing windows due to the low position of the sun in the sky.. These rooms can become uncomfortably hot for a few hours on sunny winter days and underfloor heating cannot be adjusted rapidly enough to maintain a comfortable room temperature.
 

Leo

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These rooms can become uncomfortably hot for a few hours on sunny winter days and underfloor heating cannot be adjusted rapidly enough to maintain a comfortable room temperature.
Solar gain is slow acting. and southerly facing windows would experience greatest effect during the afternoon. Underfloor heating should be thermostatically controlled so as not to call for heat, and it would be a poor installer who would site the thermostat in the northern side of the house.

I've a lot of ESE-facing glass in the kitchen / living room area that gets the full effect of solar gain on a clear day from sunrise through to early afternoon. Solar gain is easily managed via cross ventilation and occasionally in the heigth of summer, drawing the blinds a little. It's rarely an issue in winter due to the lower angle of the sun in the sky meaning solar energy is diffused as it passes a greater distance through the atmosphere.
 

Buddyboy

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I've 3m high X 10m wide south facing windows in my living room. Solar gain in the winter is a godsend as it really heats up the UFH slab, back to the back wall. It saves me a fortune in winter. And the insulated slab is a massive heatsink. In summer, UFH rarely if ever comes on as the room stays above 20degrees. sometimes, if it goes to 26, I open doors and use ventilation and passive stack ventilation (bungalow with a velux up a column), to cool it down. I've never had an issue with the room/house becoming uncomfortable.
 
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Baby boomer

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Solar gain is slow acting. and southerly facing windows would experience greatest effect during the afternoon. Underfloor heating should be thermostatically controlled so as not to call for heat, and it would be a poor installer who would site the thermostat in the northern side of the house.

I've a lot of ESE-facing glass in the kitchen / living room area that gets the full effect of solar gain on a clear day from sunrise through to early afternoon. Solar gain is easily managed via cross ventilation and occasionally in the heigth of summer, drawing the blinds a little. It's rarely an issue in winter due to the lower angle of the sun in the sky meaning solar energy is diffused as it passes a greater distance through the atmosphere.
Agree entirely. UFH with thermostats in each room will adjust for winter solar gain as the floor (gradually) heats up. In summer, you won't have central heating on anyway, and you can dump excess heat by opening windows. Anyway a high sun angle tends to minimize the amount of solar heating so it's rarely a problem. (It's Ireland after all - on how many days exactly are we too hot?!!!!) You can also leave internal doors to North facing rooms open to better distribute the summer heat.
 
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