Pex for return and supply lines for a hydronic baseboard system

Any quality PEX will do. We use PAP for applications where rigidity helps but all are rated for the same 180°F, more than enough for a properly designed fin-tube system.

We use very little fin-tube since it requires higher temperatures (more fuel) than any other hydronic emitter.

BadgerBoilerMN said:

We use very little fin-tube since it requires higher temperatures (more fuel) than any other hydronic emitter.

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Good point. If I was to overhaul my baseboard system, I would look at panel rads first, or some good old fashion cast iron rads. As it is now, I am on the lookout for some decent used ones to swap in, in place of short sections of Slant Fin in the bathrooms on the ends of my zones.

Also not sure I would use Pex for near-boiler stuff? Not sure how near to boiler the OP is talking, but it's not all that uncommon for a system to see temps up to 200 near the boiler - and maybe even into the syetem a bit.

We use copper for near-piping, mostly to support the trim--pumps, valves etc.--but most of our work is with condensing boilers. No reason to run a cast iron boiler beyond 180F so the PEX will still work. We regularly run DHW supply pipe to indirect water heaters at 180F, no problem.

Panel rads, radiant walls and ceilings are my favorite for retrofit.

BadgerBoilerMN said:

Panel rads, radiant walls and ceilings are my favorite for retrofit.

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Great thread. Would love to see some photos of these retrofits like radiant walls or panels.

I have no ducts or heating water system in my home, just electric wall heaters. Minisplits look dumb on a wall and I can't power a minisplit with wood!

But you can't cool wood!

They do make high efficiency baseboard convector units one of them is: http://smithsenvironmental.com/html/he.html

No, I have no experience with that.
I started a thread once and it has some good info, I think, anyway: https://www.hearth.com/talk/threads...s-work-well-with-gasifier-and-storage.125502/
You can always add more baseboard convectors, especially if you're starting from scratch.

I would also consider some used old-fashioned cast iron rads. They can put out some heat.

Mothra said:

Anyone?

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I've installed the Dianorm brand, although Mysom, Runtal, QHT, Buderus and others are very similar.

I like using PAP or Viega Fostapex. Both have an aluminum wrap so the tube maintains it's shape better and less expansion contraction that can lead to noise.

Delta T of 30- 40 is common and workable with panel rads, no real hard and fast rule for that. Look into TRV controls if you want individual temperature control.

Here is some good info on panel rad piping and derating, pages 9-11.

http://www.caleffi.com/sites/default/files/coll_attach_file/idronics_6_0.pdf

www.hydronicalternatives.com imports their panel rads directly from a manufacturer in Belgium. We've used tons of them and in fact have a house full going in next week.
They come 12,16,20 and 24" high X 18-60" in 6" increments. You can find the price list and btu outputs on their website along with anything you need to know regarding installation.
Drop me a PM if you need some help figuring things out but is just basics.......... What is the heat loss in a given room and how many of what size do you need to equal what you're losing. By all means, use a TRV on each rad or at least one per room. They will help get the T up as high as realistically possible.

The only rad I have had problems with is Buderus. We had a couple house that several rads rusted through and Buderus would do nothing for us on them. I heard they had a bad batch of metal that caused the problems but because they left the customer and myself hanging I have not tried them again.

We like PAP for panel or baseboard installations due to the fact the expansion ratio is far less than PEX although with panels you don't get the constant on/off cycling as you would with BB.

Mothra said:

Thank you everyone for your responses! Heaterman, I will send you a PM shortly. I've attached the heat loss calcs that i did by hand...

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An interesting "next step" just for information gathering is to calculate the btu/sq ft of floor space in each room. Use your 80* numbers.

If you look at the BTU ratings on the rad list here........

http://www.hydronicalternatives.com...6b/Stock-Flat-Steel-Panel-Radiator-Price-List

........You can easily select how many and what size you need for each room and go from there. Some of your rooms are going to require a pretty large rad or else 2 of them.
You have to figure out locations and wall space available. We find the 12 and 16" heights work best with decor and under windows but you may have to bump up to the taller models to get btu's needed.

We like to run them "home run" style from a multi port manifold like you would use for a radiant floor application. Rads require a relatively low flow rate which can easily be attained with a normal manifold capable of 1GPM per loop. When using a single loop per room remember to up size the rads because of lower temps going to the second one if fed from the first in the series. Makes for a very simple installation from a mechanical standpoint. You can run the whole house with a single pump, controlled by a central wall thermostat. Then dial each room to the desired temp. Not uncommon to see 20-30* T with this set up.

Take your dining room for example which needs roughly 12,000 btu. You're going to be hard pressed to do that with a single rad but a pair of 22 series 500x900 rads will do nicely at approx 6,000 per rad.