Baseboard heat install question.

ponjohn · Feb 22, 2013

A simple basement renovation turned into a new heating system and propane conversion (from oil).

I am getting a quote to install h/w heat in the whole house.

Contractor says that pex does not get the same heat transfer as copper and won't use pex for baseboard systems.

Anyone with experience on this?
Does it work as well as copper or subpar?

Thanks.

nehog · Feb 22, 2013

ponjohn said:
Contractor says that pex does not get the same heat transfer as copper and won't use pex for baseboard systems.

Anyone with experience on this?
Does it work as well as copper or subpar?

TO connect the baseboard units to the boiler? I don't see how one type would be any better than another--ideally they move the hot water to the baseboard and the baseboard radiates it. No heat should be transferred (radiated) from the supply lines.

Gary S · Feb 22, 2013

I would go with your contractor's suggestions. Yes, the baseboard units radiate the heat, but the copper lines between them do too, and radiating it all around the perimeter of the house will give you more even heat. That is your final goal.
And, copper can be expected to outlast plastic by many times over.

anotheroldguy · Feb 22, 2013

You mean I'm going to need to replace my Pex? What is the life of it before replacing. I was told it was the best thing to come along.

philjafo · Feb 22, 2013

anotheroldguy said:
You mean I'm going to need to replace my Pex? What is the life of it before replacing. I was told it was the best thing to come along.

Pex is the best thing to come around when you look at the other choices
Galvanized pipe- rusts from the inside out, difficult and time consuming to install
Black pipe - also subject to rusting, also difficult and time consuming to install
PVC or cpvc - cheap and easy to install, cheap and easy to break
Copper - durable and very well proven been around a long time, expensive.
Pex - low cost, easy to install, durable and flexible, hasn't been around as long as copper
So it doesn't have the track record of copper, not good where exposed to uv light or
sunlight

Copper is best for some situations, pex is best for some situations. I would never put copper in concrete, I see 25 30 year old hydronic systems that develop a leak in the concrete from the expansion and contraction of the copper. That is very difficult and expensive to fix. Your contractor has likely been doing this a long time, guys that do this for a living work very hard to stay up to date on what works and what don't. If you don't, you won't stay in business very long.

Bondo · Feb 22, 2013

ponjohn said:
A simple basement renovation turned into a new heating system and propane conversion (from oil).

I am getting a quote to install h/w heat in the whole house.

Contractor says that pex does not get the same heat transfer as copper and won't use pex for baseboard systems.

Anyone with experience on this?
Does it work as well as copper or subpar?

Thanks.

Ayuh,.... I'd think that any pipin' that's inside the baseboard panels would be Copper,....
Ya know, in the heated rooms,...

I also see No problem doin' all the tie-together's with Pex....
The stuff generally in the cellar, 'n the near boiler plumbin'...

ponjohn · Feb 22, 2013

This contractor is top notch, highly recommended and he is very meticulous.

When I get the quote I will ask him.

I didn't know if he meant the plastic didn't contain the heat enough and the water cools quicker vs copper.

Jackfre · Feb 22, 2013

The pex will do as well, but I think you have a good guy who prefers to work his way with materials that he prefers. I think you should hire the right guy and then follow his recommendations. I prefer to work with copper myself.

Tim The Tool Man · Feb 23, 2013

Here is my 2 cents: Either will work fine. PEX will most likely last longer in your situation. PEX will be more efficient than copper because it does not radiate heat like copper, - it is an insulator.

BUT PEX really looks ugly and cheap, especially when it is full of hot water and drooping between your exposed floor joists. Your installer sounds like he knows what he is doing so take his advice.

brewchief · Feb 23, 2013

A quick search and I found that much of the pex tubing is rated between 180 and 200 degrees at 80-100psi, a baseboard system would be well under the pressure rating but could come pretty close to the temp rating at times.

I personally try to avoid using any product right at it's rating.

I've run plenty of pex in radiant systems but have never used it on a higher temp baseboard system and I'm fine with that.

BadgerBoilerMN · Feb 25, 2013

Gary S said:
I would go with your contractor's suggestions. Yes, the baseboard units radiate the heat, but the copper lines between them do too, and radiating it all around the perimeter of the house will give you more even heat. That is your final goal.
And, copper can be expected to outlast plastic by many times over.

This is nonsense.

Uponor has been running a "test" on their he-pex for a couple of decades now, 180°F @ 100psi. PEX will last indefinitely.

As for more heat from copper. More rubbish.

It is true that copper transfers heat fast than PEX. It is not true that a hydronic designer considers copper distribution loss in the heating design. The fin transfers the heat where it needs to go (normally under windows where the bulk of heat loss and discomfort originates). The heat loss in distribution piping is just that, loss. In the perfect system there would be not heat "loss" except at the terminals (radiators).

Fin-tube is the lowest form of hydronic heating but if you must use it have it over-sized to take advantage of lower design water temperatures, use 1/2" PEX to supply the appropriate length of fin and use the smart contractor that knows how to perform a room-by-room heat load.

Better yet look into European style panel radiators. More comfort, more output and lower operating temperatures.

http://www.engineeringtoolbox.com/copper-pipe-heat-loss-d_19.html

http://www.engineeringtoolbox.com/physical-properties-thermoplastics-d_808.html

http://books.google.com/books?id=-E...page&q=heat loss per foot copper pipe&f=false

BadgerBoilerMN · Feb 25, 2013

I have 3000' of PEX in my 2100sf home, plumbing, heating and snow melting.

Copper costs more to buy and install without material benefits.

Gary S · Feb 25, 2013

BadgerBoilerMN said:
The heat loss in distribution piping is just that, loss. In the perfect system there would be not heat "loss" except at the terminals (radiators).

]

How do you figure that heat radiated from the copper between the radiators is lost? That is rubbish unless you are fool enough to run the piping outdoors. :eyecrazy:

Heat radiated into the house from the pipes is used to heat the house just like heat radiated from the radiators.

BadgerBoilerMN · Feb 25, 2013

This is old school. In the forced air trade, the code requires that all duct work be sealed with tape. Heat that doesn't go to the space being controlled by a thermostat may be "in the envelope" but is no t being efficiently delivered to the terminal (radiation).

Using copper at twice the cost of PEX in order to get a few hundred extra Btu's in places that you really don't want or need it is for the amateur. For those afraid of PEX, there are several manufacturers of PEX-AL-PEX with that extra layer of aluminum for the faint of heart.

Been designing hydronic systems long?

This link may help.

http://www.jlconline.com/Images/Hydronic Baseboard Basics_tcm96-1157045.pdf\

http://www.uponorpro.com/en/Technical-Support/FAQs/Plumbing.aspx

Baseboard heat install question.

ponjohn

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nehog

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Gary S

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anotheroldguy

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philjafo

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Bondo

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ponjohn

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Jackfre

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Tim The Tool Man

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brewchief

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BadgerBoilerMN

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BadgerBoilerMN

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Gary S

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BadgerBoilerMN

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