Price has no relationship to performance

ECW

Seems I am an iconoclast ... using panel rads instead of in-floor or staple-up radiant. No one seems to know much about panel rads (no problem getting info on in-floor and staple-up) - or no one is talkin'. 

There's little panel rad stock-on-hand in NA  (some great brochures but 3 months to get the product into the US). Distributors, including ones recommended on the Wall, have limited stock-on-hand.

No one provides a list of features for evaluating and comparing. Price and aesthetics are the main focus but for regular rads, all brands' stock-on-hand is basically the same shape, visuals and color).  BTW - Runtal has lousy BTUs' per panel area, volume and $. 

It takes some time for a green-horn to figure out (by studying the product catalogues) that the main differences in rads (other than price and that seems to be based exclusively on aesthetics and what the specif product line's target market will bear) are the <span style="text-decoration:underline;">lbs/ft, gal H2O/ft and pressure drops</span>.

These might be related: <span style="text-decoration:underline;">mass, volume, pressure and their impact on output</span>? But no one is talkin' about these features at all, let alone how they interact or affect performance.

<span style="text-decoration:underline;">$'s/BTU is simply not reflected in price</span>. Being limited in building space, I wanted the highest BTU's per panel (wall surface area).  If product data can be believed (i.e. BTU's and CF's are accurate), there is no relationship between BTU's and price. 

Getting straight with correction factors -  Correction factors are established based on factory measurement of output of a given rad design at a design temp. CF's cannot be cross applied to different rads (with different H2O/ft, lbs/ft, flute and panel shapes) or compared to CF tables developed based on different baselines/design temps. 

I am willing to pay more for a rad based on explained logic, field experience and research; a business case that justifies paying more for lower heat bills; for faster reaction time; or longer retention time; corrosion resistance (i.e. life cycle costs). 

Weight per linear ft (thickness of steel, quantity of material)

Water volume per linear ft

Heat transfer rate (from supply H2O to room)

Radiation emissivity

% space heat due to radiation vs convection

Radiation diffusion patterns into a room based on rad surface texture, color and shape

Man, am I naive.

 

Charlie from wmass

Buy cast iron then

It lasts it works and they are prettier. Of course I am bias. Try Burnham or Governale

ECW

Blast from the past

I am using a condensing boiler and average temp of 130F - the Burnham and Govrernale don't show performance below 150 average temp so I have written to them.



Can those beautiful and endearing cast iron rads work at this lower temp?  Also, we are piping (pexing) to/from the wall cavity, not below. I have been warned off cast iron by low temp/low energy promoters but frankly  I like them stream beasties a lot



I am not sure that quality and price go hand in hand in the panel rad business (its a commodity business) - whereas they may in the cast iron rad business they do.

Ted_4

You bet!

Cast iron rads work beautifully at lower temps.  My home system was orginially gravity (converted to pumped hot water in the 30's), so it was set up to use cooler water.  The radiation is about twice what would be needed with water at 180 degrees.

I now use a modcon with outdoor reset.  The system target temps range from 100 to no more than 150 (at zero outside).  Heats well and is very comfortable.

Charlie from wmass

They are heavy

This is one reason. Also used rads can be iffy. THe cast iron can be bad for some mod con boilers but not others, check with boiler manufacturer to confirm if they are compatible. Heating alternative has valves to use radiators and connect to pex or other small pipe and give thermostatic control. also it would keep pipes on one end of the radiators. The high thermo mass of the radiators would be great with low temp water if sized properly.

CMadatMe

This Should Anwser Your Questions

Check out the attachement

NRT_Rob

you are way overthinking this.

panel radiators are currently, practically identical in terms of output for area as long as the radiators are similar in dimensions. Generally price differential IS based on aesthetics or other factors. Runtal, for instance, is a much more rugged radiator than most of the "white rectangles" out there. It'll hold up to junior throwing things at it much longer. and it's customizable in every dimension. so it has benefits. but for the low end cost range, it wouldn't make much sense.



But cost and output are not even passingly related in radiator land.



these are visible emitters. Are you really surprised that aesthetics matter and change pricing?



Your whole $/BTU metric is not terribly helpful. Beyond Runtal and a handful of other high end radiator manufacturers, all the rest are in the same price and performance ballpark, typically. If you're going high end, you're going high end for aesthetics or durability, unless you just can't get the output you need without a custom sized radiator.



Mass, volume, pressure.... not very helpful. Personally I like more mass in my radiators. because I use reset and flow controls, it's not a problem. But there are arguments for less in the radiator and more in a buffer tank.



If you want the best cost/output characteristics, I'd do a lightweight plate radiant ceiling.



Good luck!

ECW

perhaps ...

Linear foot compared to linear foot - if I can believe the brochures and the company provided CF's, Runtal doesn't have the BTU's, so its not even in the running.



Hard to put a ceiling radiant system in a cathedral ceiling after its designed and built.

NRT_Rob

why the meta-data?

size the radiator in each product line if you're going to do that far and compare pricing and features and appearance.



probably faster to do that than it has been to have this conversation. Not trying to be flip, I guess I'm just trying to say the "level of surety" you are going for is not achievable without an independent test laboratory. I applaud your desire to get there, you just can't at this time.