Where to put radiators in odd shaped room?

[PointyDogs]

We are in the middle of an extension build, and need to figure out best location for radiators. I've attached a plan so it makes sense! We are definitely putting one (a vertical radiator) in location R1, facing into the room. DH thinks we need one facing into the top left area where we'll have chairs and floor-ceiling bookshelves on both walls, as he is convinced it will get cold. I think we should have the second one facing towards the kitchen, and the heat will circulate round. If we have it where DH wants, we'll lose bookshelf space (we have a lot of books). Both rads will be fairly high powered as it is a big space, but with good insulation in roof, floor and walls. The top part is single storey, the kitchen end is two storey, with doors opening to utility room and hallway.

I don't want the reading area to be a cold spot, but I also don't want to lose bookshelf space! Can't find any advice online so was hoping someone here had done something similar and could advise.

[PointyDogs]

Trying that image again...

[PigletJohn]

if you have a long low radiator, it need not run so hot and will give a more even heat. There are a few "skirting" radiators at great cost, but I think the smallest ordinary ones I have seen on the UK market are about 250 or 300mm high.

The heat from a rad is almost all convection, so goes up, not "forwards" in the direction it is "facing"

If the radiator is somewhat oversized and has a TRV on it, the TRV will throttle back the heat to maintain your chosen temperature. Like taking your foot off the accelerator. But if the rad is undersized, there is nothing you can do to make it give out more heat.

Your pics are too small and I can't read them. Except in small rooms, you get more even heat with a rad at each end than with a double-sized one at one end.

[PointyDogs]

Thanks, not sure how to make the image bigger, it expands when I click on it. The top end (back of the house) is a little under 9 metres, with two 3m bifolds and some velux windows. The right side about 6.5 metres, around 45sqm in total. So if we don't put a radiator in that top left area, will the heat still circulate around to it from the other areas? If so, then problem solved, I just don't want to create a cold zone!

[PigletJohn]

could you put a long low radiator along the end wall, top left? Or top left hand corner at least? It is a long way from R1. You don't want one end of the room to be cold. A room 9m long certainly needs a rad at each end.

I would put one in the lower position marked R2 as well.

How is the kitchen area heated?

Will you have thick lined curtains across the large window, and are the walls CWI?

You will need a 22mm pipe going into that extension, don't let the builder try to add it on to an existing 15mm for an existing radiator.

If the floor is not yet poured, have you looked at UFH? There will never be a better time to add it.

[PointyDogs]

Thanks for the help, its appreciated

We had considered UFH (we are having engineered oak flooring throughout), but last time the boiler was serviced we asked the engineer and he wasn't sure it would take it - its an old boiler we are planning on replacing in a couple of years probably, but are trying to avoid the additional cost right now. But thinking about it, we are removing three standard radiators from the rooms we are combining - is there much difference in draw on the boiler from 3 separate rads and UFH?

The only floor poured (concrete only, no insulation or screed yet) is the old conservatory, the top left part of the diagram, the brickies are still working on the new outside sections. Does wet UFH go into the screed, and does it affect the thickness of the floor, or is it incorporated within what is already planned to go down?

No separate heating for the kitchen, we were looking at 2 rads with the highest output we can find to do the whole area. The lower R2 would do the kitchen I thought. No curtains planned - we are lucky enough to look out over farmland, so privacy not an issue. Walls are filled, roof will have I think 110mm insulation in total.

[ChunkyHare]

I am sure on Pinterest I have seen where someone has a radiator with a radiator cover on it and above that a bookcase so you don't lose the wall above the radiator. Hang on,.....

here or you can get more modern versions of the radiator cover.

I would have a radiator in both those positions marked R2 if the boiler will take it, and then you can always turn them down if it is too warm.

Double radiators kick out some amazing heat so it shouldn't have to take up too much room and if you shelve above you aren't losing too much valuable book space.

[LizzieMacQueen]

I would have R2 facing the island. Any chance you can put a woodburner in between your two patio door sets?

[PointyDogs]

LizzieMacQueen I so wish you hadn't said that...it never occurred to me but I can picture it perfectly...sadly I think the budget and timescale (they have just started on the roof), not to mention DH, won't allow!

[PigletJohn]

the insulation slabs usually go on the raft, then the UFH, then the screed. But there may be other ways to do it. Suspended wooden floors have it on trays between the joists.

Due to the delay while the concrete heats up, it is common to set the UFH to come on an hour or two before the rads, so the boiler will not be trying to heat them both from cold at the same time. Unless your boiler is very old, it is not likely to be too small to heat the house. The total heat loss of the house will be the same whether you have rads or UFH or a combination, and modern houses often need less than 15kW, but you will have more power than that if a combi, because hw needs much more. If necessary you could have the upstairs and downstairs, or the cylinder if you have one, zoned for different start times. If you're thinking about it, you ought to consult a UFH specialist, even if you have to pay him to measure up and make a recommendation, the sooner the better.

[PigletJohn]

p.s.

With no curtains, you will get cold air flowing off the glass. Even the finest double glazing is nowhere near as good an insulator as a wall with CWI.

[PointyDogs]

Quick follow up - we're getting the plumber round next week to price up UFH for us. Apparently he also does woodburners, so he's going to talk to us about them too . Thanks for the suggestions.