Radiators...Under floor heating...

[atlasfever]

Hi folks,

I have a question about radiators and underfloor heating.
Background: Total refurb of georgian flat, including lifting floorboards, so I have the opportunity to redo piping.

1. Radiators: My biggest room is 25 feet by 16feet by (height) 12 feet with 3 large 1st floor single pane windows about 9 feet high. I used one of those BTU calculators online and somehow arrived at almost 30,000 BTUs. At the moment, each window well has one radiator (ugly, 80s version, box shaped) which would be replaced. The width of the window well is about 1 metre i think, and height before the bottom of the window is likely only 2.5 feet. So, one can not fix the largest of radiators there. An architect suggested that 3 of those small radiators would not provide enough heating in winter. The kitchen is similar to the living room, but 2 windows wide so roughly 2/3rds the width, but same dimensions for the rest.
Question:
a. If I put in those old fashioned chunky metal ones, could I get away with just doing it in each window well? or, would I need to had a row of them along one of the back walls? I am not very excited about this idea. But, if a chunky one (2.5 feet wide, 2.5 feet high) only produces like 4000 btus, then I would only have less than half of what is required.
b. I saw a chrome version of the chunky ones. WOW. But, the price made me almost cry. Maybe black gloss paint instead

2. Underfloor heating (water, not electrical): I could do this option apparently, but am concerned the new wood floor I will be adding may warp, etc. I heard some walnut floors can take the heat (special engineered boards), but does anyone have any experience with this? Maybe this is a totally crazy idea, to add underfloor heating to a period property.

What do you think folks? Keep in mind that I have decided to lay a walnut or oak on top of the orig floor boards (incidentally, not original floor anyway) and have to lift the boards so that sound dampening can be added anyway. And, I got the impression that the cost of replacing all of my radiators is not that much less than underfloor.

Thanks, A

 

[worms]

atlasfever,
I have little expertise on this, but my understanding was that in these really big airy rooms, it was often not possible to put in enough normal radiators to adequately do the job without being too intrusive, so the better option was a fan assisted convection unit such as this. (You describe an 80's box-shaped unit, which may be an older version of this type of heater.)

Also, since underfloor operates with a lower temperature of circulating water, unless your room is well insulated and draught-proofed, it may not adequately heat the room.

But I am sure others with more knowledge will happen by soon!

 

[MdB]

It sounds like you have poor insulation so you need a lot of heat input. You can do this with underfloor but it will require high temperatures (though not as high as radiators) to get the required transfer. I've been told that this can cause problems with people finding it uncomfortably warm for their feet. Our underfloor runs off a heat pump at lower temperatures (40°C in, 30°C out, approx 25°C floor temp) and this is fine - in fact it is lovely. Unfortunately for you, this set up does require a very well insulated house - we have 6kW of heat output for the entire house which is a fraction of what most people have.

(oh and BTU's is a measure of Energy rather than Power so is useless for indicating how much heating your house requires - It should come with a time period to make any sense. I would guess per hour but you need to state this.)

 

[atlasfever]

Hi,

Ok, so I am still confused I think I need to do some reading on this one. You make some good points:

1. I don't think there is any insulation (1st floor georgian flat). I am pretty sure it's plaster on brick, and I have a corner flat, so 2 exterior walls. Grrrrrrreat for heat loss.
2. Single pane windows. I can't (for the life of me) figure out why I can't add double pane slimlite panes to my non-orginal window sashes (they are deep enough already), but I've been told that council will very loudly say 'no.' Whatever, I have to chalk that one up to 'crazy town.' Afraid if I ask too much, council will make me use fireplaces instead of radiators
3. I will be adding/refurbing the sashes to good draught proofing.
4. The convection ones sure are rather unattractive, but will keep an open mind.

Overall, I thought the issue with underfloor heating would be that the new wood floor could warp --- I never thought that maybe it just wouldn't be very effective too.

Hmmmmm......

 

[worms]

I've been told that council will very loudly say 'no.' Whatever, I have to chalk that one up to 'crazy town.'

I'd be careful not to believe everything you are told about what the council will say, far better to get it from the horse's mouth.

4. The convection ones sure are rather unattractive, but will keep an open mind.

Myson used to do a more attractive wood-framed version but it may be what you describe as an "ugly 80's wooden box"!

 

[MdB]

Overall, I thought the issue with underfloor heating would be that the new wood floor could warp --- I never thought that maybe it just wouldn't be very effective too.

It only won't be effective if run off a heat pump. Normal gas / oil will be fine - it is just that the floor temperature might be too high for comfort. I don't know this for sure but it is something I have heard can be an issue. Something to research.

And yes, floorboards warping is a potential issue too - speak to the manufacturer of the boards, they should know what is possible.

 

[AMc]

2. Underfloor heating (water, not electrical): I could do this option apparently, but am concerned the new wood floor I will be adding may warp, etc. I heard some walnut floors can take the heat (special engineered boards), but does anyone have any experience with this? Maybe this is a totally crazy idea, to add underfloor heating to a period property.

What do you think folks? Keep in mind that I have decided to lay a walnut or oak on top of the orig floor boards (incidentally, not original floor anyway) and have to lift the boards so that sound dampening can be added anyway. And, I got the impression that the cost of replacing all of my radiators is not that much less than underfloor.

Thanks, A

Yes, you can add underflooring heating in a period house with wooden floors BUT...

I have underfloor heating and radiators driven by a air source heat pumps (ASHP). Parts of our house are very well insulated with the equivalent of a foot of mineral wool on the walls, others less so with solid walls but we're double glazed through out and all the floors are insulated underneath with copious ecotherm boards. In winter when the outside temp drops to 0C the heat pumps supply a flow temp of 55C which is more than they're really efficient at supplying but that's what it takes to keep the house warm. That doesn't result in uncomfortably hot floors here.

In many rooms we fitted new engineered boards with a deep "antique" oak veneer on the top, these have been floated over solid floors and nailed in the suspended ones. None to date has shown signs of cracking or warping after 3 heating seasons at comparatively high temperatures. They came from here http://www.vanillawoodfloors.co.uk/
In other rooms we kept the original wide pine boards and again they haven't shown any damage - but it's worth mentioning they have been "seasoned" by more than 100 years of being nailed flat to the floor!

We have radiators in a number of bedrooms which we were told would need to be replaced to deal with the lower flow temperature from the ASHP. In practice this hasn't been the case and they're OK with the radiators from the previous oil installation mainly due to running them at a higher than designed temperature.

A typical gas boiler will feed radiators at around 65C which is certainly too much for the wood so if you are retaining radiators elsewhere so you need a mix down valve to lower the flow to a suitable floor temperature.

It's worth bearing in mind that underfloor heating is generally better with solid ceramic and stone floors than with wood. Stone and tile conduct heat while wood acts as an insulator. Your plan to relay the floorboards then another floor over the top will significantly reduce the capacity of the floor to heat the room. We put a large rug down in one room with a wood floor and discovered it dropped the room temperature by over 1C!

You also mention sound insulation, my underfloor heating isn't very noisy but there is a sound of water circulating and it tends to run most of the time in the winter, often all night. I would seriously question if this is a good idea in a flat - or even if your leasehold allows it.

One point of good news is that the effectiveness of underfloor heating varies according to the size of the room. Larger rooms have more heating surface to edges which lose heat, so it actually becomes more practical with larger areas. e.g a 2m x 2m room with two external walls has 4m2 of heating to 4m of edge (1:1). A 4m x 4m room has 16m2 surface to 8m of edge (2:1) and onwards...

I wouldn't recommend underfloor heating unless your flat is pretty energy efficient already or you intend to make it so. We kept our original windows where they were still here and fitted secondary glazing behind them which is almost as effective as sealed unit double glazing and is often used in conservation areas and listed buildings. Serious draught proofing is needed and where you can insulating the walls is wise.

It might be possible to mix some radiators and some underfloor heating to meet the demands of your flat but it wouldn't be a simple solution and it certainly won't be cheap. My advice would be to speak to an underfloor heating specialist, in my experience plumbers can easily fit them but you need to be sure it will work. If you fit it, lay £1000's of flooring and then discover its noisy and ineffective it would be a real problem to put right. The balance between fitting an efficient underfloor system and fitting one that doesn't work is pretty fine. With a rads and boiler system plumbers generally over spec the boiler and rads by a factor and if the house is colder than the estimates then you crank up the flow temp. With underfloor you don't have the option of turning up the flow very much before you make the room uncomfortable and damage the flooring.
I used these people, I'm sure there are plenty of other suitably qualified companies out there, check the self building and renovating magazines http://www.renenergy.co.uk/product-detail.aspx?item=underfloor-heating

 

[atlasfever]

Wow,

Thanks so much for the feedback. I still have a lot to learn, but will discuss with the plumbers and will check out the links you sent.

Now, to find chrome chunky radiators at a reasonable price

 

[LadyArowana]

Now, to find chrome chunky radiators at a reasonable price

When you have accomplished that miracle could you turn your attention to diamonds please, some large ones of those at a reasonable price would be lovely, thank you :lol:

 

[JoceAndChris]

Hi Atlas

Robgil is the man for advice on how to turn scabby old heaps into beautiful gleaming period radiators cheaply. Hours of work though.

I also really appreciate AMc's wonderful post on UFH, as I still wonder about putting this in the bathrooms, but it really does sound unsuited to my sieve of a building and as though I'd be better putting the money into more cashmere and electric fan heaters.

Anyway, this isn't really my business, and your building has been chopped about so much I'm not really wearing my conservationist hat. But your floor looks fab, and you want to spend 1000s on a new one, when you need absolutely everything???

http://www.periodproperty.co.uk/forum/viewtopic.php?t=12829

I wouldn't give UFH another thought, I'd be thinking of replacing the rads with lovely ones, or even just covering the ugly ones with made to measure window seats with lovely scatter cushions, I'd be wanting the fireplaces working and I'd be ringing Toby Newell, who will be able to make your old floor look so lovely you won't believe your eyes:

http://www.floorsanding-uk.com/Gallery.html


And I agree with please don't jump on the bandwaggon of thinking the Council a bunch of nutters who won't let you at least secondary glaze your windows, such utter nonsense is talked about COs and there's a great deal of ignorance in the general population about what can and can't be done, as said above, it's best to get it from the horse's mouth.