replacing radiators

[Simon Finnigan]

Hi everyone, I'm looking to have my 35 year old radiators replaced with modern ones. A lot of the panels are only a single panel, and will be replaced with double panels where there is a need for more warmth - the hall way for example. The combi boiler is more than up to the job, but are the any issues to be aware of before I start getting people in for quotes?

Also I'm wanting to move a radiator to the opposite side of a room, to allow a patio door to be installed where the radiator currently is. The easiest way would be to run the pipes feeding the radiator horizontally along the top of the wall before running them down to supply the radiator. Taking them through the ceiling wouldn't be the preferred option as it would mean repairing or replacing a perfectly good ceiling, and the pipes wouldn't bother us being run visibly. Are there any reasons not to do it this way?

Thanks for your help.

[Tricky Dicky]

You need to give more details of the construction of your property before any useful advice can be given.

Richard

[Simon Finnigan]

Bog standard brick built house with cavity wall insulation fitted. Concrete floor on the ground level, with plasterboard ceiling onto wooden joists.

[Simon Finnigan]

Worcester Bosch 35 IIRC, but I'm not there at the moment to check. I'm looking to replace two singles with doubles, and the rest will be replaced like for like.

To run the pipes across the room would take quite a bit of messing about to tidy it up properly, and it would need to re textured to match the existing ceiling. Running them boxed in just below the ceiling would be a lot lot easier :-)

[Mike Barnes]

Not what you asked, but IME opposite the window is the very worst place to put a radiator. It creates a steep temperature gradient across the room, and the resulting air circulation makes the room feel colder than it is.

[Andrew Gabriel]

I would do a set of heatloss calculations for each room, and work out what power output you need. Then work out what radiator sizes you need to achieve this (possibly allowing for low temperature condensing operation, even if you don't have one at the moment).

Then look at how these sizes you have calculated compare with what you currently have - for example, this will hopefully show up your existing hall one as too small, by way of confirming your calculations.

Anyway, you will now have the power required for each room, and it's a matter of chosing the number and shape of radiators required to meet this.

The pipes will generate dirty heat marks on the nearby ceiling over time. Do the radiator pipes currently come down from the ceiling? If not, you will need a means to bleed air out of the two pipe runs, and also to drain the radiator as it won't be able to drain over the loops. Is there a nearer feed by taking the radiator supply from another room?

Radiators are ideally put against outside walls, because that would otherwise be the coldest part of the room. If you put them against an inside wall, you will create a larger temperature gradient across the room. If there's also a roomstat in that room, you also need to consider its position versus the radiator (not above or close-by, and ideally not on the opposite wall facing the radiator).

[Capitol]

I haven't found this to be the case. I did this in a room and fed the new radiator from a unit in the next room through a wall. This gave 2 radiators in parallel but in different rooms, worked twice.

[Nightjar]

You really ought to take the opportunity to do a proper heat loss calculation for every room and size the radiators from that. There is no guarantee that the radiators you have now are actually the right ones for the rooms.

If you have a suspended wooden floor and the joists run parallel to the patio door, you can get a radiator that drops into a trough between the joists and has a floor grille to release heat in front of the patio doors. It can be done with a concrete floor, but that involves a lot more work.

Dirty marks on the ceiling above the pipes. Can you not access the space above the ceiling by lifting floorboards above?

[Simon Finnigan]

It will be on the adjacent wall not the opposite sorry, the radiator will be the opposite side of the room from where the pipes currently enter the room.

The window (and replacement door) get a LOT of sun throughout the day and the room is consistently one of the warmest, even with the radiator turned off. The temperature gradient isn't something that will come into play in this room, but thanks for the idea.

[Simon Finnigan]

The house used to be fine, it's the change in use and having to keep all the downstairs doors closed that is causing the real issue, in that rather than the radiators in three rooms being able to heat the air rising up the stairs, now only the hall radiator is doing this job. A bigger radiator here would be useful (and is one of the main reasons for doing this) and the radiator in the bedroom could do with being better as well. And a radiator, not a towel rack thing, in the bathroom, so that the room can actually heat up :-)

I'll have a look at the calculations, can anyone suggest a good website to make life easy?

It's a concrete floor throughout, which is why I'm looking to take the supply pipes along the top of the walls rather then hide them under the floor.

It can be done, but not easily - it would mean moving a lot of heavy furniture to access the floor boards across the area the pipes would be running.

[Nightjar]

...

About par for a typical DIY job then :-)

[Simon Finnigan]

It would likely involve having to try and move either fully assembled double wardrobes, or a fully built double bed, out of the room entirely. Neither item of furniture is really up to being stripped down and rebuilt either.