Baseboard water system temperature question

Tom Elam

Hey,
I need to insulate the pipes for my hot water baseboard heating system that run through my crawl space. Our Weil-Mclain Ultra boiler stops firing when the outlet temperature is about 186 degrees F. I believe I can change that set point by about 20 degrees in either direction.
I have investigated my insulation options. Closed cell ½” thick has an R value around 2.6 and can withstand more than 220 degrees. The double foil insulation with the bubble wrap core has a much higher R value, the only problem is the bubble wrap will start to melt around 180 degrees. From a cost standpoint the foil is about 1/4 as much as closed cell.
I could lower my temperature set point to 170 degrees to prevent damage to the foil’s core. but what effect will that have on the system’s ability to heat the house? I read somewhere a hot water baseboard heat system needs to run from 160 to 200 degrees. There is the option of wrapping the foil around the closed cell insulation.
What would you recommend?
Thanks,
Tom

Weezbo

my thought is,' insulate the crawl space....unless on perma

frost buh even then i insulate anyway and as of date no home that i have insulated on permafrost has melted its way through the earth or whatever the engineers would have the bankers belive

Ken_8

Neither of your pipe insulation options are

appropriate.

They make fiberglass pipe insulation specifically for this application that is durable, high in R-value, easy to install and less expensive.

Knauf is just one of many brands available. Various wall thicknesses are available and a tough white pre-glued adhesive covering is included. They even make transition pieces to do tees and elbows.

Check it out http://www.knaufusa.com/index.cfm?fuseaction=prd.dspProdDetail&ID=1.

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Constantin

I second the call to insulate your crawlspace...

... that's the first thing you should do. Take a look over at Building Science Corporation on the how and why, they maintain a fantastic web-site, chock-a-block full of useful building-related data. They also publish a great series of builder guides for different climates... my builder is still digesting my copy...

Once the house is tight, and insulated from below, it's not just your pipes that will benefit... I am a fan of XPS since it's very resistant to picking up water and has a reasonable R value (5/inch) that therefore can be relied on.

As for the pipes, I'd avoid bubble-wrap at all costs. The stuff works great in outer space and anywhere else you have primarily radiant heat transfer. However, as a barrier to conduction and convection, they have been shown to be wholly ineffective... Since your house is not in outer space, may I suggest the more pedestrian options like quality fiberglass wrappers?

Dave_16

insulation

Briefly, why isn't closed cell foam appropriate? We moved into a house with foam wrapped on most of the hot water lines to the baseboard (<190F) - and I was wondering if fiberglass would be better...

elamcup

Hot water baseboard heat uses radiant heat to warm my house, I want to keep it in the pipes in the crawl space. My crawl space it 10 degrees warmer than my living space. To me that is wasted money.

elamcup

Thanks Ken,
I checked out thier site. I like the fact that foil is used in thier insulation also. You are the man!
Tom

Weezbo

heat goes to cold dark bodies,first.

any thing about cold dark bodies resembeling the crawl space? insulating the pipes to me is reactionary (run go fix it responce)you insulate the pipes and then the crawl space becomes cooler? then what?serrendipitously the laws of physics will change?

elamcup

heat to cold

is that by conduction, convection or radiation?

Constantin

No question...

... warming that crawlspace is wasting heat down there. Furthermore, there is no question that insulating the pipes is a good idea. However, consider the benefits to your house of insulating the crawlspace to prevent the migration of water and heat...