Hydronic: question about Argo & Runtal

[toffee]

Not sure where to post this question. Mod, if this is wrong forum, please move it. Thanks.

I am converting to hydronic. Lots of things to learn, one of which is:

I would like to know the difference, pros and cons of Argo vs Runtal, performance, noise, efficient, installation, etc. etc.

Argo calls their product baseboard. Runtals calls their product radiators and are costlier. Since Runtal also makes a product (their 8" and 10") that shares similar dimension to Argo, once installed, they look similar?

Any advise would be much appreciated. Thanks for helping.

[acwizard]

They are both very good products. You will need to know the heat loss calcs for each room , Once that is determined then selection of the radiators can be chosen.

[beenthere]

Moved to AOP Residential forum.

[skippedover]

Since you didn't specify any particular product numbers, I'll assume for the moment that you're talking about baseboard style products. The differences between Runtal and Argo are significant and should be recognized as two entirely different products.

Argo baseboard is a convection type of heat, meaning it uses a finned copper baseboard to transfer the heat from the hot (normally about 180°F) water flowing through the pipe to the aluminum fins. This raises the temperature of the air immediately above the fins and causes it to rise out of the baseboard enclosure to be replaced by cooler air that enters at the bottom of the enclosure. This continues for the duration of the heat cycle. The greater the water temperature, the faster the air circulation occurs. Since it requires air movement to heat, it is called convection heat.

The Runtal panels on the other hand are painted steel radiant heat panels. That is, they do NOT require air movement to provide heat to the room. Their output also varies according to water temperature but since they are radiant heat panels they can supply great heat over a wide range of temperatures, beginning with very low temps for the warmer days and increasing water temperatures for cooler/colder weather. As radiant panels they send out waves of energy that become heat when they strike an object. This is the same principle used for radiant floors/walls/ceilings.

The comfort levels achieved by the two products are different and distinct. The finned baseboard will be quicker on/off and will feel cooler during dwell cycles when there is no call for heat. The radiant panels on the other hand will warm just as quickly but will cool down much more slowly, thus providing heat even during the dwell cycle. The Runtal panels will also let you take full advantage of a condensing boiler in that you can heat your rooms at significantly lower water temperatures, thus allowing the boiler to condense for entire heat cycles rather than just the warm-up time of a high temperature application.

If your budget allows, I'd go with the radiant panels and a modulating, condensing boiler for best comfort and greatest long term efficiency/cost.

[toffee]

Thank you guys for helping out.

skippedover: I think that I will go with Runtal as Mysons are used in some other rooms. They are similar, aren't they? Both being radiators.

If the water temp is say 140 deg or so, wouldn't a tankless water heater be "workable" too to save some initial cost? Perhaps at the expense of longevity?

Thanks again for helping.

[skippedover]

Yes, a water heater could be used if allowed by code in your area. That's not allowed in mine except through a heat exchanger. There are many suitable boilers on the market and though they are pricey, they're designed specifically to do the job. A water heater is designed for an entirely different job and would typically used for only a small room where a boiler output would be way too much.

[CraziFuzzy]

Tankless would work, but many tankless water heaters say they are not designed for 'continuous flow' (like in a hot water recirc system). They also would not really modulate the water temperature like a more advanced boiler (I still hate using that term for these) would. Well, meaning, they would always shoot for 140°F, for instance, so the only way to modulate the heating to a given room is via a modulating control valve for the space.

[toffee]

Regarding water temp. For hydronic baseboard, it would be 180deg. For radiators, what would be the agreeable "low range" temp? Would 140 deg be too low? Radiator (Runtal and Myson) runs at about 60% output at 140deg vs running at 180deg.

I am how much saving would one realize by running at 140 deg vs 180deg for a home of 3000ft2, with winter temp around 40deg (Calif, Bay area)?

[beenthere]

I have a buddy who runs his water temp at 110 for his cast iron rads, and they heat his house fine. Even when its 0 degrees outside.

Copper baseboard still emits heat with 120 degree water.

Water temp is determined by type and how much emitter you have compared to the heat loss of the house.

[toffee]

Those Runtal and Myson radiators are fairly pricey, needs a lot more radiators if running at low temp. I am trying to figure out how much saving one can realize at the broiler/water heater to justify more radiators.

[tedkidd]

Lots. And an outdoor reset will allow for automatic water temperature adjustment. So if you are a little shy, adjust reset to provide higher temp water when it gets cold.

Look at Navien combi, it'll take care of heat AND hot water at only slightly more than a good condensing tankless.

[meplumber]

Just a note on Tedkidd's post.

The Navien Combi is not H stamped as a boiler. (As of my last inquiry). It is Navien's first model to separate the boiler and domestic waters.

In some jurisdictions, a boiler must have the ASME H stamp as a central heating boiler in order for it to be installed as much. The same problem exist with tankless water heaters.

Your contractor will know what is allowed in your jurisdiction. I personally will not install a tankless unit as a boiler. Never.

The key to the whole project is a proper heat loss calculation and a qualified knowledgeable contractor. Check references and talk to his other clients. Trust his experience and ask questions.

Good Luck.

[acwizard]

I would not even think of using a tankless water heater for your application. The maintenance cost of descaling the heat exchanger and additional repairs makes it not practical. Look into a Munchkin boiler , Noritz boiler, Triangle Tube boiler or you may want to look into a condensing water heater like Polaris, Phoenix or Vertex by AO Smith. Another issue is you will need to treat the water if using Runtal radiators do to their steel construction. This means a closed system. If price is the deciding factor , then hydronic heating may not be the correct choice for you. There are a 1000 different ways to heat a building.

[tedkidd]

2 good posts. Jumped to solutions too quickly without understanding lay of land, didn't I...

How is house heated now? Why are you changing to radiant? Have you had an audit to define deficiencies and assess opportunities, or is this going from your gut?

[toffee]

Not challenging your opinions as I am very ignorant about Hydronic. I have seen European homes used combi tankless water heater to provide hot water and warm house with radiators.

Different tankless or just homes are smaller?

[toffee]

2 good posts.

How is house heated now? Why are you changing to radiant? Have you had an audit to define deficiencies and assess opportunities, or is this going from your gut?

An Old flat roofed house, built 100 years ago with 6-8" of crawl space and no heating. We used electric space heaters for bedroom and gas fireplace inserts for living area.

relocating and putting this old house for rental. House in very high rent area, so lack of heating not a good idea.

So force air would be difficult due to lack of accessible space. Electric is one way to go but high operating cost? Thought 1/2" water tubes would be doable.

Just planning at this point.

[tedkidd]

Tankless water heaters are typically designed with 35-60f incoming water temp and 110-130 outgoing. This is a fairly consistent operating parameter that is NOT the situation a boiler deals with. Boiler may deal with 120f return temp (incoming), for example.

A wall hung boiler and a tankless water heater are not the same, although they may look the same to most homeowners.

[acwizard]

An Old flat roofed house, built 100 years ago with 6-8" of crawl space and no heating. We used electric space heaters for bedroom and gas fireplace inserts for living area.

relocating and putting this old house for rental. House in very high rent area, so lack of heating not a good idea.

So force air would be difficult due to lack of accessible space. Electric is one way to go but high operating cost? Thought 1/2" water tubes would be doable.

Just planning at this point.

Electric space heating is not an approved method of heating in Calif. Heating is required by building codes. Spacepak or a Unico heat pump may work for you, or even Mitsubishi or a Fujitsu mini split system heat pump. A lot more info is needed to steer you in the right direction.

[tedkidd]

Mini split.

There I go again...

Get an energy audit.