Efficient Hydronic radiators

Gcracker

Other than Runtal VX/VLX series, which are far outside my price range, what other highly efficient hot water radiators are out there? I am looking to replace standard CFT baseboard that I have too little of. Have a Bosch Greenstar 151 Mod-Con Combi and 3/4 PEX.

kcopp

You can add Higher out CFT.
Some examples are Sterling Senior, Sterling Petite 9, HE3 silent fin.
Or you could do panel radiators.
The key is to design/ Size them to run at lower water temps.

nicholas bonham-carter

Do a room by room heatloss, using the SlantFin App, and see where you are lacking radiation in each room, comparing the needed heat with the capacity of what you have.
Radiators only differ on their “Thermal Mass”, and mixing cast iron with baseboard is a bad idea for instance in the same room. Do you have room for more baseboard?—NBC

Gilmorrie

Hydronic radiators are, by their nature, 100% efficient - but they have different thermal output at rated conditions.

Brewbeer

I used the Heat Trim Plus model from Sterling in my system. I installed about 95 feet of this model, and with the ends and other finish trim pieces, it came to about $20 / foot for materials only, that I picked up from a supply house, using a truck. I also installed 30 feet of the smaller Heat Trim model in lower heat loss rooms. The smaller Heat trim puts out about 35% less than the larger Plus model, and was about $15/foot materials. (Just baseboard materials, no piping or fittings).

Smith's baseboards have some of the highest output, but the baseboard is very pricey.

Attached is a data table from the research I did on Sterling baseboards.

bob eck

HE3 Heating Edge and Sterling Synergy is a great copper baseboard to use with an condensing boiler / combi boiler.
Ecostyle aluminum radiant wall panel heaters. F W Webb sells them.

Solid_Fuel_Man

If you like and can source, cast iron which has been used on water or two pipe steam (connected on the top). I sandblasted and painted with automotive paint in my second floor. Very economical, just work and hauling them! Cast iron baseboard is also an option, but harder to come by in my experience.

Gcracker

Gilmorrie said:

Hydronic radiators are, by their nature, 100% efficient - but they have different thermal output at rated conditions.

Oh, yeah. That makes sense. I should have said higher output per foot.
I was looking at the VLX units, and got excited about the BTU/foot, even at lower temps. My home has too little baseboard to begin with, and after the factory and the HVAC company sort out who will fix what, I think I'd like to get enough higher output emitters to run true condensing temps.

Gcracker

bob eck said:

HE3 Heating Edge and Sterling Synergy is a great copper baseboard to use with an condensing boiler / combi boiler.
Ecostyle aluminum radiant wall panel heaters. F W Webb sells them.

Thanks for these brand suggestions.

Are the two factors affecting the output of these baseboards the two-pipe design and more fins closer together?

Also: Hot DAMN! There's an F W Webb two miles from me!

Gcracker

nicholas bonham-carter said:

Do a room by room heatloss, using the SlantFin App, and see where you are lacking radiation in each room, comparing the needed heat with the capacity of what you have.
Radiators only differ on their “Thermal Mass”, and mixing cast iron with baseboard is a bad idea for instance in the same room. Do you have room for more baseboard?—NBC

Here is the output from a heat loss calc I did a few weeks ago. I came up at 31,489btuh loss vs 21,521btuh the manufacturer performed. The red font shows what is actually installed, and output of installed baseboard at 130F. Green and orange colored fonts show how many feet of the same baseboard needed to achieve the calculated loss at lower temperatures, listed above the table



I am pushing for some changes by the manufacturer related to the amount (and possibly the type) of baseboard, but when that is said and done, I may add more baseboard of my own choosing to allow lower temps and add water volume.

Here is a very crude drawing of the heat loop and rooms. Note: Bedroom 2 is above the portion of the basement where the boiler is, so for simplicity I drew it there. It isn't in that bedroom.

bob eck

I would look at using the HE3 Heating Edge 3 copper baseboard.
One pipe going through bigger aluminum fin. This give more BTU heat transfer.
What F W Webb branch is near where you live?

Steamhead

You might also look at Slant/Fin's Multi-Pak 80. With the H-1 element it will give 840 BTU per hour per foot at 4 GPM and 180° F:

http://www.slantfin.com/wp-content/uploads/2015/11/MultiPak-80-Catalog-Sheet-718.pdf