Having cold feet about underfloor heating: please share your wisdom!

[BellaGallica]

We are extending the kitchen/diner of an old house and we're having second thoughts about installing underfloor heating. The UFH would be wet pipes installed in a timber floor (ie not concrete) and we want to put engineered wood on top.

The more people I ask about this plan, the more confused I am getting. The plumber has previously installed UFH only with ceramic floors. He reckons that UFH would probably need supplementing with radiators as the space is large (about 40 m2).

I've spoken to a couple of engineered wood suppliers. One said engineered wood is absolutely fine with UFH and the flooring should cover the whole room and go under all appliances and units. He did say though that he never gets involved in UFH; his business is just the flooring surface.

Another wood supplier said that engineered wood must not go under the kitchen units and appliances where there's no UFH because otherwise there will be temperature differences. He also said we'd need a thick ply underneath so the full floor thickness would be about 3cm and wouldn't let that much heat through. He's not a fan of UFH with wood floors!

I'm starting to think that if we will need radiators as well then the UFH is an expensive and complicated extra which we don't really need. Has anyone got experience of this to share?

[OnTheBottomWithAWomansWeekly]

Not sure about your issues, however a friend of mine is a teacher in a school which got UFH and every teacher keeps a pair of slippers or bigger shoes under their desk, as by the end of the day in winter everyone's feet have swollen up a size!

Also, if you have a bin on the floor, it will go smelly v quickly.

Just some more info to add to the mix.

[BellaGallica]

Thanks -I'm not so worried about being too warm; I always really feel the cold! I'm more bothered about spending loads of money but still needing radiators, which seems to kind of defeat the object of the exercise...

I had heard about the smelly bin issue; the bins will be under the sink & not heated.

[nocake]

An interesting article about the pros and cons.

I've been researching UFH for a garage conversion and have pretty much decided against it for two reasons. Firstly, it takes longer to heat up so you really need it on a separate circuit from the boiler with its own valve and controller. Secondly, you shouldn't put floor mounted furniture over it which is a problem if you have free standing wardrobes, bookcases etc. in the room.

[BellaGallica]

Thanks nocake; useful article. I think it confirms my suspicions that wood is not ideal because of its insulating properties. The last thing I want is to spend a fortune heating up the underside of my floor!

[AViewFromTheFridge]

I'm not sure whether the pun in the title was deliberate or not, but it made me chuckle!

[matilda101]

We have water ufh with engineered wood in on our ground floor and I cannot rave about it enough. I love it, it doesn't take long to heat up and it's such a nice heat compared to rads (we have rads upstairs). We are in the process of building a new house and we will be having ufh everywhere. It's easy to install, cheaper to run (you only have to heat the water to 55 degrees c rather than 75/80 which you need to do for rads. We have wall space as we don't have any radiators which makes a massive difference as we can put furniture where we want! All of our rooms are a separate zone so have separate thermostats which is great as we can set the living room at a higher temp than the kitchen etc.

Our wood is from broadleaf www.broadleaftimber.com/products/wood-flooring

They also do a really nice floor which we have in our kitchen called Byron squares - might me worth a look. We'll be using broadleaf on our new house as well!

[BellaGallica]

Thanks matilda; do you mind my asking if you have solid concrete floors under the UFH or do you have a timber suspended floor? From what I can make out, the sub-floor seems to make a difference as to how the heat is transferred.

AViewFromTheFridge: yes, intentional pun in the hope of getting some interest in a fairly boring technical subject!

[MrsTaraPlumbing]

Interesting thread.
I have some ufh in my house - but under tiles and not under furniture.

I notice a couple of points in the thread.
The water temperature can be a lot lower than rads - it could be about 30-40 or even lower, over 50 sounds quite high. But if you are having a new GCHwith rads system installed from scratch the water in your rads will be lower (probably between 40-70) compared with older radiator systems.

• another person said about hot feet - their temperature is definitely set too high.
  

Yes long warm up and long cool down times are associated with UFH - but varies because there are many different ways of installing it. Many people think of it as something you just leave on all the time - so use differently from GCH with rads.

I don't think you would need rads if you have UFH. Rads can striggle to wam a room because of air movement and furniture, but UFH does not have this problem.

Sorry - can't answer all your questions, just had a few things to through in. There are many UFH system manufacturers in this country and it could be worth getting in touch with them with your questions.

[MrsTaraPlumbing]

Interesting thread.
I have some ufh in my house - but under tiles and not under furniture.

I notice a couple of points in the thread.
The water temperature can be a lot lower than rads - it could be about 30-40 or even lower, over 50 sounds quite high. But if you are having a new GCHwith rads system installed from scratch the water in your rads will be lower (probably between 40-70) compared with older radiator systems.

• another person said about hot feet - their temperature is definitely set too high.
  

Yes long warm up and long cool down times are associated with UFH - but varies because there are many different ways of installing it. Many people think of it as something you just leave on all the time - so use differently from GCH with rads.

I don't think you would need rads if you have UFH. Rads can striggle to wam a room because of air movement and furniture, but UFH does not have this problem.

Sorry - can't answer all your questions, just had a few things to through in. There are many UFH system manufacturers in this country and it could be worth getting in touch with them with your questions.

[Eastpoint]

We have just been working through this process for our kitchen. We have decided against underfloor heating as we cannot get enough heat from it, there is a formula you or your plumber can use to calculate it. We would have ended up with less than half the amount of heat we needed.

[Cosmosim]

My relatives have this (and their winters are routinely -15c)... They love it. It's especially great with kids who play/crawl around the floor as the floor feels wonderfully toasty without the room feeling stuffy and hot. They love it.

[YoniOneWayOfLife]

One of the builders we were considering refused to use wet UFH without radiators, he said it would never work. Well, it does We have two rooms with wet UFH in screed and real wood over (and I did lots and lots of research over engineered vs real and went for real and I'm glad, we have engineered elsewhere and it does not look as nice) We also have an adjacent room which has a suspended wooden floor - so ground/earth, suspended joists with wooden floor on top. There is some arrangement with celotex either side of the pipes. I think it's sheet of ply/celotex/pipes/celotex/floor but I'm not entirely sure. Compared to the screed floor, it's not as warm, but that is toasty. In fact, the part of the house that is new (i.e. properly insulated) with UFH is so much warmer than the rest of the house with radiators.

[Deux]

We went through this dilema recently for a large openplan space with lots of glass.

I could not get a definitive answer as to whether UFH on its own would be enough or rads would be needed too. We were using engineered wood as the space included the kitchen.

My fear was that it would be OK for most of the year but in the depths of winter it would be chilly. And I hate feeling cold.

In the end we decided against UFH and I don't have any regrets at all. We saved about £12k by not having it.

We went for tall, slim aluminium rads with a very high BTU output and they are fabulous. They heat up super fast and we had to turn the thermostats down. We'll definitely be toasty in the depths of winter.

We were able to site the rads in places where we would not have put furniture anyway eg gap between the wall and where the bifolds start.

[musickeepsmesane]

we went for UFH in our extension. The floor is concrete. We used laminate on top as it lets heat through. I am not sure about a timber floor as the best bit about the concrete is it heating up. We never put pipes where we knew there would be permanent items.We also have lots of glass. The glass also heats the room so in summer we don't use the underfloor at all. In winter it is on very low and it is a very comfortable even temp. No hot feet! You do lose a little bit of wall for all the 'gubbins' technical term I am very pleased with the way it heats a large space. The only downside was the christmas tree! It lasted 2 days

[BellaGallica]

Thanks so much everyone for your collective wisdom. It does sound as if UFH is much more effective in screed than with a timber suspended floor. I've reviewed my plans again and found some suitable spaces for rads so I think I'll scrap the UFH option and save the budget for somewhere else.

The point about the Christmas tree is also a bit of a clincher. DH and DDs are total Christmas romantics and they would probably opt to switch off the UFH for a few weeks rather than give up their beloved real Christmas tree. That's a risk too far for me...