Recommendations.............For new system

[cirks]

Ok, possibly a bit open ended but I'll clarify where requested.

We've recently moved and the house (1924) has a mixture of plumbing installed. This is predominantly joined by large bore glavanised pipes but in the extensions added in the '70s and the pipes to the showers etc are std copper. I know this mix is not exactly the best! The rads in the lounge and dining room are the old 'school' type (ie like the currently fashionable ones just considerably older and less efficient!) and others are pretty much single thickness non-finned ones (?20+years old). All upstairs rads are of this type

What I'm looking for are thoughts/recommendations on a system to replace what there is.

The current boiler is a Ideal Concorde. Hot water cylinder in airing cupboard. None of the rads have thermostats and there is no thermostat for the heating at all.

The house is good size 4 bedroom with decent size kitchen, large L shaped lounge (approx 25ft * 12min/18max), dining room (12*10), family/play room (18x12). The walls are part cavity filled (other parts are 8" thick).
As for plans, most of the house will remain carpetted but if/when we extend the kitchen (currently laminate floor) and extend to create breakfast area, utility room etc the floor is likely to be tiled. The hall will probably go to wood (not laminate) as might the dining room and family/play room.

Layout is roughly:

[code:1]
---wwwwwwww-------wwwwwwwwwww__
| | |
| | Family/Play |
|R | |
| | |
| |______ _R__ _|
| C |C |
/R | R\
|R Lounge | R |
\R | DR R/
| | |
| | |
|______________ __| ________|..........
| Hall | | .
|______________ _ | | .
| | | .
| | Kitchen | .
| |B | .
| | | .
|___| | .
|loo| | .
|___|____________| .

R are current rads (the ones in the bays are school type)
w patio doors
B boiler
C fireplace/chimney
... future extension

[/code:1]

As just about everything is going to be ripped out (we're getting wiring done too so floors will be up) what is the current 'best quality for sensible money' system that would be suitable for the above. I'd consider underfloor or electric as well if anyone on this forum believes in them!!

 

[oilman]

The rads in the lounge and dining room are the old 'school' type (ie like the currently fashionable ones just considerably older and less efficient!)

Don't confuse rubbish with fact. The radiators may need flushing out, but using words like efficiency is meaningless unless you state your conditions. They have a longer time constant, and the room temperature will fluctuate less than with pressed steel ones. I know which I'd have if I had the money.

 

[brumylad]

If possible I too would keep some of the old rads, especially if those in the bay windows were custom made . It might be worth investigating wether new valves could be fitted if the old ones are hideous. As for the rads themselves, if the aesthetics are poor, it might be possible to shot blast them and respray.

I would have underfloor heating in the Kitchen when you extend.

I would go for a good quality conventional system boiler supplying energy to the central heating and an unvented hot water cylinder. With a new installation you might consider putting solar collectors on the roof.

 

[ChrisR]

I'd agree entirely withthe above post. Underfloor heating is a very slow-to-react form of heating, but very comfortable and no ugly rads. If I was in a lot I'd have it in the lounge too.

 

[cirks]

Thanks for the comments so far.

Don't confuse rubbish with fact. The radiators may need flushing out, but using words like efficiency is meaningless unless you state your conditions. They have a longer time constant, and the room temperature will fluctuate less than with pressed steel ones. I know which I'd have if I had the money.

I'm happy to be told I'm talking rubbish as it means that I get good advice from here rather than someone telling me that I have to replace everything! I quite like the school type rads and if I can clean them up and flush them etc then would be quite happy to keep them. As they are all fed (and joined) by large bore pipe work is this a problem or can all/some of it be replaced with copper? The old valves are the large 'tap' type so I would want to ideally replace those.

I would go for a good quality conventional system boiler supplying energy to the central heating and an unvented hot water cylinder.

I know some of you will have different opinions but what is generally considered 'good quality' these days - I've had a look through a number of the other posts and Worcester etc seems to crop up a lot but not much in the form of rad makes etc. Any pointers etc?

Underfloor heating is a very slow-to-react form of heating, but very comfortable and no ugly rads. If I was in a lot I'd have it in the lounge too.

That I think is my biggest fear/problem. I would like some underfloor because no need for rads etc but both my wife (part-time) and I (full-time)work so aren't actually in the house a lot. Anyone tried the underfloor stuff under carpets etc (I know Nu-Heat do it) - can it be efficient (in these terms - actually warming the room in a sensible timescale!) or as cheap to run as a rad system?


Apart from the obvious problem of modern designs 'dating', what do people think of some of the 'more interesting' radiator designs available these days. Do they make sense from a thermodynamic point of view or are they just 'for show'? Which makes are worth looking at if any?

 

[oilman]

I'm happy to be told I'm talking rubbish as it means that I get good advice from here rather than someone telling me that I have to replace everything! I quite like the school type rads and if I can clean them up and flush them etc then would be quite happy to keep them. As they are all fed (and joined) by large bore pipe work is this a problem or can all/some of it be replaced with copper? The old valves are the large 'tap' type so I would want to ideally replace those.

I was not suggesting YOU were talking rubbish, it's that this view is proffered for all types of radiator, that one type is more efficient than another. Heat goes in, heat comes out, efficiency is not a good parameter. I have replaced a boiler and converted a system to fully pumped that was originally built to run on gravity with 35, 28 and 22 mm pipes (well, imperial equivalent) with the "school" type rads. I would leave everything that doesn't NEED replacing, and I'd keep the valves They will be expensive to replace unless you replace the pipework. You probably have many decades of life in the old parts of the system with appropriate maintenance.

 

[cirks]

Oilman, thanks for you comments.
With the large bore existing pipe work being galvanised is it an issue? With the type of mixed bore systems you've done do you have to replace the old pipes so that there isn't the mix of copper and galvanised? We've been told the mix is an issue.
So, if we try to keep the school rads then what would you suggest for the rest of the system etc. I know without seeing it it is difficult for you but anything I can discuss with prospective plumbers around here (where are you) would obviously help.
Not sure about whether we will be able to keep the valves as several have been leaking in the past and a couple of others definately need a good overhaul etc.
With the layout as I've drawn it, what is the best solution as far as thermostats etc are concerned?

 

[kevplumb]

you can still get valves for old cast rads
make sure you are sitting down when you get the price tho

 

[PTH]

As Kev says the replacement valves for large connections on rdiators are expensive but are available up to 1 1/2" BSP.

The mixture of galvanised steel pipe, chemical treated steel (panel rads), cast iron (cast sectional rads), copper pipework, gunmetal, brass fittings, all sorts of different metals in your new boiler is not really a problem as the system is effectively sealed. Once the water is in there it will gradually get de-oxygenated, helped by whatever inhibitor gloop you add to the system. It is the oxygen content in the water which accelerates corrosion.

Do be careful with any flushing chemicals, some of these are very aggressive to galvanised surfaces.

When you do start using descalers, inhibitors and other stuff make sure it is suitable for those materials.

As for advise on system types and efficiencies, you can only really consider the efficiency of the system as an overall installation. The heat that is derived from burning x amount of gas/oil/coal/peat/wood/elephant dung is tranferred to the water which is circulated. When that heat leaves the boiler in the water it is either given up into the rooms by the radiators and emission from pipework, or it is transferred to the domestic hot water in the cylinder or it returns to the boiler.

You can improve heat transfer rate by removing layers of paint from rads and you can improve your heat conservation by adding insualtion to the fabric of your house but radiators, old or new give out radiated heat based on surface area and convected heat on design. If you like the old radiators, keep them; they won't be any less efficient than new ones.