Worth paying extra aluminium radiators?

[bobgroups123]

Hi,

We are modernising a bedroom i.e. changing the wooden flooring adn while doing this want to change radiator - room is a bedroom. Looked on the net and read about Aluminium radiators being quicker to heat up and more energy efficient as they use less water.

Looking to go for 652 height x 800 wide. Saw one on the internet for £126. Was told it is rated as 1072 watts.

Any views on aluminium radaiators as we are replacing thought of putting aluminium in - main reason more energy efficient and quicker to heat up.

Please advise anyone.

Thanks,
Bob

 

[JohnD]

yes, it's a marketing gimmick intended to separate you from your money.

£126

Since the heat is carried into the radiator in the water, if the radiator contains e.g. 50% less water, the water will have to move through it twice as fast in order for the boiler to deliver the same amount of heat to it.

 

[GuessMan]

If you can afford them, I would go for the aluminium ones.

Fondital would be my choice, and here are the reasons why:

High quality powder coat finish
Sectional design allows for easier handling
10 year guarantee which can be extended to 20 if you have them internally coated.
No sludge build up through rotting iron in the system
Built in Auto air vent option
And the big one, they are designed to work on a flow temperature of 50 degrees. Which is perfect for modern condensing boilers and even renewables.

Heating technology has moved on and the big plates of iron no longer fit the bill

I don't work for them but have fitted them for two happy customers.

 

[JohnD]

I can see those points would fit perfectly in an advert.


Where does the idea come from that they are more energy efficient?

What is the customer gaining for his extra money?

Does aluminium corrode?

 

[Agile]

So muich marketing hype!

All rads work at any temperature!

They are all 100% efficient. All the heat they lose heats up the room!

Aluminium may have a higher thermal conductivity but in rads it has to be much thicker so thats irrelevant.

In any case there is virtually no temperature gradient between the water and the air because air is such a poor conductor of heat.

Any decision to choose ali rads should only be based solely on their appearance!

Tony

 

[mickyg]

i would say if your were changing all your radiators definitely if you can afford it. They dont cause the corrosion in systems like steel panels.
We have an estate near us with 25yr old alu rads in townhouses, about 16 rads in each property, were all open vent for first 20yrs or so, some still are. Been to numerous properties, no inhibitor in most of them and the water is crystal clear. They use them alot in germany, which may explain why they dont bother with inhibitor. For just one rad though, not sure you'll get the benefit, they do heat up quicker(metal transfers the heat quicker) and look nice.

 

[bobgroups123]

hmm thanks all for the info so far. Can anyone advise if i am working out the BTU correctly. Room is 10'6 (3.2m) wide by 13'6 (4.11m) long x 11 feet high (3.35m) and there are no external windows. Had an extension done and kept this as a bedroom so this room still has a patio door that simply leads to another bed room. Therefore no external windows. Room is on ground floor. Flooring is going to be solid wood flooring on top of wooden floorboards. Therefore what BTU output of a rad can i go for as a minimum.

One calculation site gave me 4202 BTU's reqd /1231 watts, although i put one window on the calculation criteria.

 

[bobgroups123]

Just wondering if anyone has a chance to reply to my BTU question. Any feedback greatly appreciated. Thanks

 

[SimonH2]

Was told it is rated as 1072 watts.

One thing to bear in mind is that radiators don't have "an" output rating (singular). If you look at manufacturers specs, they will give multiple tables - and you choose the table that corresponds to your flow & return temperatures. Alternatively, they will give one table for a single flow & return temperature, and a set of factors to apply - eg if running at 50/30˚C instead of 70/50˚C, they may say to multiply the values in the 70/50˚C table by something like 0.5 to get the output with a flow temp, ie the rad only puts out half the heat.

The output also varies with room temp (if the room is colder, you'll get more heat out of the rad) - and the effect will become more significant with lower water temps.

 

[Onetap]

No sludge build up through rotting iron in the system

And the big one, they are designed to work on a flow temperature of 50 degrees. Which is perfect for modern condensing boilers and even renewables.

Aluminium is further down the galvanic series than steel, so you'd expect more corrosion of the radiators in a galvanic corrosion cell. Why don't they corrode?

They were banned by a local authority I worked for, a long time ago. Some of the acid cleaning solutions could have an unhappy outcome.

The heat emission would depend mainly on the surface area. You can get steel radiators that work (give a rated heat emission) at 50 degC. It has virtually nothing to do with the material.

 

[Dan Robinson]

I would say my cheapy steel rads give off far more heat per unit area/volume than the ponsy designer ones we have made from aluminum.

Could be down to design though as the steel ones all have fins and the pretty ones don't.

Personally I like the standard flat panel ones like like thee Monza range, but they are still over priced for what they are.

 

[big-all]

as has been said the output can be no more no less than the input
all systems should be balanced so each radiator it taking the correct amount/percentage off the input if your radiator was taking out more than its fair share then it it would need to be rebalanced/flow reduced

more efficient in this respect means the radiator steals heat from elsewhere in the system so the only gain means possibly a smaller radiator can do the same job

in other words unless the radiators are cheaper to buy they are less cost effective and more expensive throughout there lives so increase installation costs with no reduction in running costs

 

[Agile]

Aluminium is further down the galvanic series than steel, so you'd expect more corrosion of the radiators in a galvanic corrosion cell. Why don't they corrode?

Perhaps its because of its ability to form protective oxide layers?

Copper and steel are probably about the worst combination of common metals!

 

[JohnD]

Big-all's mention of cost effectiveness is highly relevant here

People speak (inaccurately) about expensive radiators being more "efficient" than cheap ones (in fact they aren't, but let that go for now)

If a rad uses heat costing, say, 5p per hour x 10 hrs x 7 days x 20 weeks, say, in a typical winter, £70, and you hoped for a 10% efficiency saving = £7 per year

then a flashy radiator costing you £100 more than a cheap one, would take (£100 / £7) 14 years before your "efficiency" started to save you money (in fact, since expensive radiators are not more efficient than cheap ones, you would start £100 down and stay £100 down for ever)

If you consider expensive radiators to be more beautiful, then you are of course at liberty to spend your money on them as domestic ornaments, but don't be fooled into thinking you are doing it to save money.

 

[mordim]

A very interesting discussion.

Anyone linked any scientific studies to the properties of Aluminum?

It is used for it's non-rust properties and if anodized even more so yes?

How much do system flushes and constant use of inhibitors cost?

The corrode side of things relates to it's pitted oxide layer which stays put no? as in external cases takes age to scrape off.

It reaches a certain depth and stops depending on the mass it is attached to.

Thermal conductivity of Aluminum is darn good no? only copper gold etc. better.

If it is the thickness of the Aluminum for strength that negates it what about fins as used by heatsinks?

If anyone can elaborate on these issues that would be great.