PEX and RIH

[Shelley]

I was moaning a while back 'cause I couldn't find a plumber interested in doing RIH.  Guy from Abq offered to come down, but schedules never worked out.  We let the locals beat us down and never got pex in the shop floor.  I was determined that the house would have RIH regardless of what I had to do.

Talked to Radiantec.  Altho friendly, helpful and professional...they were a little high for us.  Wanted the same amount for just the materials that I'm used to paying for an entire system where all I do is watch.

How hard could this be?  Famous last words.  Got the Wirsbo design manual and layed out  4 zones.  Got the supplies from an Abq supply house.  Posted a couple of questions on heatinghelp.com that were quickly answered by a RIH designer.

We did it today.  Four of us.  We'd only watched in the past...they'd never even done that.  Beer was cracked open in 4 hours, 3 minutes.  It really isn't that hard.  Easier than we thought in fact.  One of the few times I've ever said that.

I would have purchased the supplies from partsguy.com if I could have waited for shipping.  Came highly recommended and prices were slightly cheaper than I paid with a discount at the supply house.  Found another site that seems interesting but know nothing about them.  pexsupply.com.  Got several useful tips from radiantdesigninstitute.org.

There've been several threads in the past about RIH, so I know that some of you are thinking of this for heat.  Just wanted you to know that it's quite doable.

[Dustin]

I hope you don't mind, but I am planning radiant heat in my home and am looking at all the options.
What is your heat source (hot water heater or boiler, and what kind)? Is your system an "open" system or a "indirect" system with a heat exchanger?
How much did it cost and how many square foot did you cover?
Thanks for the info.

[glenn kangiser]

I did about 200 sq. ft. in my cabin as an experiment -- I had excess plain 1/2" pex so just put it under the floor in rows abut 12" apart.  I run my cooling water from my generator through it and pick up the heat from my generator when I charge batteries during off solar/wind times - I could hook it into my wood fired hot tub heater with another hours work.  It works fine but not real cold here so I don't worry about it much.

I probably used about $60 worth of pex.

[Shelley]

Dustin,

Heat source as yet undetermined.  Would like to avoid propane (gas boiler) if we can.  We'll probably do some kind of Glycol system for the RIH and domestic HW.  What to do about night?  Owner of AAA Solar says that with our climate and construction method solar should do 80% of it.  Last 20% will be very expensive if done with solar.  Since we're not zealots, we're considering just a pellet stove for backup....which Chuck says would be fine.  Haven't really decided.  We'll do whatever gets us the biggest bang for the buck, pays off in a reasonable time, makes sense to do.

Costs so far.  More expensive than they need to be.  We ran four <300' zones.  Could have done it with three.  Our choice. The pros on a house this size would put the bath and bedroom together.  We've had houses configured that way.  We've decided that we'd like the baths warmer than the bedrooms.  Then, since we have a manifold remote from the utility room, had to buy a 300' roll of 3/4".  Used hardly any of it.  The pex, strain-relief brackets, the twisties, some pipe insulation, pipe shields cost $1000 including tax and UPS from Abq.  With a different floor plan and doing it as three zones probably $500-$700 for the same square footage (1410).

Though I've seen plenty of applications where a HWH is used for a boiler.....CW around here is that the temp is hard to regulate over about 1000-1200sf.....and using it as a boiler tends to shorten the life.  Dunno, never done it.  Not talking about the combo systems.  Talking about using a regular HWH.

[Shelley]

Hey Glenn,

Since you said "had some pex left over"....assume you used the pex for supply lines.

That used to be OK here, but now against code.  People should check with their code people b4 they do that...assuming inspections are an issue.

[Dustin]

Been wondering because I'm moving to a cold dry mountain enviroment that gets about 45" of snow a year. I have never lived in such a climate before, having spent most of my life in balmy southern CA and just recently in freaking hot central AZ. It might be a bit of a shock for us, but I think I will enjoy having seasons where I live.
I have been looking into Radiantec and others and have been getting differing opinions about which system to use. I would like to do solar but am daunted by the cost, so I figure I should be able to design a system where I can add solar input later if needed and I can pay for it.  Radiantec says the best way to go is a super-efficient HWH in an open system, where the HWH heats your tap water and the house. I have read in other places that this is a recipe for death by legionella disease and other places it isn't. I don't know who to believe on that topic, so I think I might want to be safe and buy an efficient propane boiler and a heat exchanger, even though it's more expensive. I have to talk to more people who've "done it" first.
Our house will be a two-story woodframe 1700' sq ft. with a 750' sq ft. basement.
I was thinking I would put in radiant in the basement slab and staple-up on the first floor. I'm not sure if I'll need to do the second floor too, relying on the warm air from the basement and the first floor to travel up to the bedrooms. I need to consult with someone on this. I plan on putting in a woodstove for backup and recreation as well.

So in NM you can't use PEX for regular plumbing supply lines? I asked a plumber in Utah and he said the standard there is PEX and I would have to pay extra to do copper. My first house was PVC and the house I have now is copper.

[Shelley]

No, pex for supply lines is OK here.  But, there's differing pexes.  What's now illegal here is to use the aquapex (supply line stuff) for RIH.  The RIH pex has an oxygen barrier.  Aquapex doesn't.

I think that Radientec makes sense if you live in their part of the country.  Prices there for installs are way higher than here.  Makes sense to pay a little more than I to get all the support that they offer.  But, they wanted 6k for the parts.  I'm used to paying 6k for everything from pex to thermostats...sitting in my lawn chair watching.

If you're using a regular system with maybe solar in the future....last one I had was a Weil-McClain combo thing.  HWH was a tank within a tank.  No heating element.  Boiler water pumped into the inner tank which became a heat exchanger.  Very simple.  Super insulated.  Think the specs on it stated that the water temp only dropped 10 degrees in 24 hrs.  No complaints about that one.  HWH cost $500 instead of $250.  Very reasonable.  80 gal tank.  

Surprised that you think that heating water with solar is expensive.  Pretty old established technology.  Straight forward.  Have you checked AAA Solar?  In business for years.  See references to them on the solar/alternative sites.  Think their site is aaasolar.com.  They're into simple.  More I think about it, guess it is expensive.  Good cast iron boiler <1k.  Solar panels are $1200 each and they'll be more than one.  But there's the lack of gas bill.  Guess I'll be happy if I can make it payback in <5 yrs.  If not, have to rethink it.

All this solar stuff is a bunch of theories.  Maybe more than one will work.  That's what makes it so confusing.

[glenn kangiser]

In our area PEX is approved for hot and cold as it is in Oregon where my cousin is a plumber.  The entire apt. complex I just worked in in Sacramento was plumbed in it - a different brand but same stuff I think.  Fire sprinkler lines were orange pvc of some sort in parts of the complex also.

Some of the plumbers unions in Southern Cal. were trying to keep it out due to the fast installation time.  I guess they could just do more and make the same money the way I see it.

Do they give you legitimate reasons for not allowing it or just made up reasons to support some official's cousin who is a plumber, Shelley?

[glenn kangiser]

I've got you now--- I knew that the floor stuff had the oxygen barrier - I didn't ever find out what it does - the local supplier here thought it would be OK for experimental and is totally separate from my domestic system.  May be codes here if I asked- in fact I guess there are--must have forgot -- I'm just playing anyway. :-/

I do go by the codes for my customers though.

[Shelley]

I think it's the oxygen barrier thing.  Air getting into the system can cause pump failures, pinhole leaks at the expansion tank, sludgy buildup in the system, boiler failures.  Oxygen getting in causes rust and all its inherent problems.  That's why they outlawed aquapex here for RIH.  It's less expensive, plumbers were using it 'cause it wasn't prevented by code, homeowners were unaware and stuck with the repairs.

Pex I used had printed on the side "not for potable water".  HEpex by Wirsbo.

[glenn kangiser]

That sounds fair -at least a good reason for the prevention of standard PEX use -

I guess if there wasn't a problem Wirsbo wouldn't make the other product.