Under floor heating. How efficient?

[Gfplux]

My daughter is in the process of buying off plan a one bedroom flat.
It comes with under floor heating as standard.
My knowledge or memory of underfloor heating is from 30 years ago when efficiency was questionable. I am assuming this is now state of the art but wonder if any one here on Lemon have experience or knowledge about this type of system.
The builder/developer claims the energy certificate will be AAA. The Windows will be triple glazed.
Thank you

[redsturgeon]

Is it a wet or a dry system?

I have a wet system (pipes under a screed) in my kitchen which runs off my CH boiler but my bathrooms have a more modern dry system (electric elements under the tiles).

http://www.thermogroupuk.com/electric-u ... ning-costs

The electric system is more likely I think in a new flat and this site gives running cost of 2.1p per square metre. I guess a modern one bed flat is about 50 sq metres, so that would be £1 per hour. In a small well insulated flat with triple glazing though I would be surprised if you needed the heating on at all for much of the year.

John

[Gfplux]

Thank you for your reply. It goes to show how out of touch I am not knowing there were two types.
Reading the specification I see it will be a wet system. It will be laid on an insulated floor covered with a screed. Then the floor will be finished with tiles although for extra price parquet (real or laminate) could be laid.
Are there any positives or negatives for underfloor heating with tiles, wood or laminate?
Thanks

[redsturgeon]

Thank you for your reply. It goes to show how out of touch I am not knowing there were two types.
Reading the specification I see it will be a wet system. It will be laid on an insulated floor covered with a screed. Then the floor will be finished with tiles although for extra price parquet (real or laminate) could be laid.
Are there any positives or negatives for underfloor heating with tiles, wood or laminate?
Thanks

A wet system will actual be cheaper to run and has many benefits over traditional radiators. As long as carpet is not laid then there should be no significant issue with either wood or tile as long as it is the right specification for UFH.

Benefits include a more even heat, fewer cold spots and no unsightly radiators taking up wall space this allowing more freedom in placement of furniture.

The big drawback of wet UFH is the cost of installation so in a new build it is a real bonus to have it fitted already.

John

[PrincessB]

The builder/developer claims the energy certificate will be AAA. The Windows will be triple glazed.

I am somewhat surprised to see that they are going to the trouble of installing wet underfloor.

A friend bought his first flat a couple of years ago. It is a relatively modern build (Within the last 10 years) penthouse (I should add it's only a one bedroom penhouse) with 10 foot ceilings and a huge amount of glass. The heating is delivered from storage heaters which also incorporate a fan heater for instant hot.

He claims to have never turned the heating on as the flat warm enough regardless of the weather. As a caveat, he's a very energetic friend so I often get quotes like 'I woke up at three in the morning and could not get back to sleep so I went for a 20 mile bicycle ride and then went to the gym for a couple of hours before going to work. My response is to tell him to run to the pub and get the first couple on the bar while I stroll there.

I have asked on here, or perhaps on the old board about underfloor heating and one response you've not had relates to the time it takes to warm up a room - My understanding from the advice was that you basically set a temperature and leave it on. If you come back to a cold flat after a few days away underfloor is not going to make it toasty warm quickly.

You might consider a baseboard heater for the kitchen/diner and a small fan heater for the bedroom for the odd occasions when it does get chilly. They might get very little use, but the ability to get a room warm fast is always a bonus.

B.

[niord]

We have the wet underfloor heating and I we love it.

We have wooden floors in the main rooms, carpeted bedrooms and stone floor tiles in the kitchen/bathrooms and it feels lovely underfoot especially on the warm tiles in the mornings

It does take some getting used to in that you do not get instant heat but we just leave the thermometers set to the desired level 24/7.

It also helps if the house is well insulated.

[Raptor]

A wet system will actual be cheaper to run and has many benefits over traditional radiators. As long as carpet is not laid then there should be no significant issue with either wood or tile as long as it is the right specification for UFH.

Benefits include a more even heat, fewer cold spots and no unsightly radiators taking up wall space this allowing more freedom in placement of furniture.

The big drawback of wet UFH is the cost of installation so in a new build it is a real bonus to have it fitted already.

John

What an apt topic. My architest called me to say the council building dept want the concrete floor dug up and made more insulated as the amount of glass we are having means the current floor does not come up to standard (there was I thinking that removing the conservatories and replacing with a permanent structure was simple, no all the walls are not up to standard so need knocking down and larger gaps and insulation) anyway thought if they are having to dig down then lets go for my first request and have underfloor heating, originally the builders said the expense of doing that was not warranted, but now? I like the idea of no radiators and my floor people (creative flooring) have said that the Kearndean floor would be OK if :-

Karndean Design flooring is suitable for installing over underfloor heating systems, providing they have been insulated so that the surface temperature does not exceed 27°C (80°F).

Not sure what the costs will be to install, but that is not a worry, the future costs maybe though. Anything is better than too hot to use in summer and damn cold in winter.

Raptor.

[BrummieDave]

Note also that there are two quite different types of dry (electric) systems: those that simply heat the floor (typically in a bathroom so the flooring does not feel cold, but the room itself is heated by a radiator), and those that heat the room (in lieu of radiators typically in a downstairs modern extension).

I have both, and the latter is (as you would expect) a great deal more expensive to run than the former, and a great deal more expensive to run than any form of gas central heating (again as you would expect, electricity being a product converted from a primary fuel such as gas).

[TonyB]

We also had a 'wet' UFH system installed when we had an extension built just over a year ago and love it.

The floor surface is Karndean and the system thermostat operates at a 'Day' level and a 'Night' level (recommended by the supplier to be a minimum of 4C lower). We've also just had an energy Smart meter fitted so can now easily see daily usage, for the month of December this has averaged about 85 kWh for a floor area about 90 m^2. The weather has been relatively warm so far.

We haven't found the UFH to be noticeably slower to warm up than our previous radiator system. It will be interesting to see from the Smart meter whether having 2 temperature settings makes sense.

Raptor, wrt Karndean, not sure what the floor people mean by the '...providing they have been insulated so that the surface temperature does not exceed 27C...' The 27C level should be achieved through the design of the system, usually carried out by the supplier of the UFH piping and controls and not by insulation which would seem to defeat the purpose of UFH: lots of insulation underneath the slab and minimum insulation above it.

The only problem we had with our installation was that the concrete slab took an awful lot longer to dry than we expected > 3 months

TonyB

[Gfplux]

I now know a lot more, than you all.
I have also learnt that there will be a radiator/towel rail in the Bathroom so the underfloor heating will cover the rest of the flat +/- 50 sq meters.
Later in the building process I will hope to understand what controls/thermostats will be installed.

We live in Luxembourg and many houses have basement garages with a sloping drive running from the pavement to the garage door. This can be "fun" in winter when the snow has to be cleared. The gradient is partularly steep in older houses in the centre of the city. In the last 12 months I have seen under floor heating (wet) being laid on the drive of a house being renovated and on a new build. An interesting and I imagine an expensive solution to an old problem.

[dspp]

Not as expensive as the electric pavement heating in many upmarket shopping streets (I first saw it in Telluride) !