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[D2082]

We are about 1/2 way through building a new house and I've purchased a OWF to heat the water and the house.  It'll be hooked up to the hot water heater, HVAC and ran through the basement slab for (hopefully) good radiant heat through the house.  I bought a Hardy H25 and it should be installed in the next couple months.  Didn't research these things too much before purchasing but have a couple of buddies with Hardys and they are pleased with them.  Looking forward to discussing these things on here and learning - I'm def a novice with these things.   

[hondaracer2oo4]

Welcome to the forum! I have a hardy too and while they are not the most liked owb in this site they do their job and hold up well. The manufacture date on mine is 9/91!!!

[D2082]

Nice!   My dealer just replaced his Hardy and I believe he said he installed the old one back in 1988!  That was enough "proof in the pudding" for me.  Appreciate the welcome, I'm looking fwd to learning from this site.  And yes I've noticed that Hardy isn't the most popular stove on here.  That's interesting.  It's good to know that I'm not on the Hardy island by myself! 

[cartod]

I did the same thing you are doing.  My one question is will you be using your basement or will it be unfinished.   Here is why I ask: 

The basement slab heat (radiant) is nice comfortable heat but I'm not sure it's the best way of heating (or most efficient) if you won't be living down there.   You are heating an extra _____ sq ft for null.  The warm slab in the basement does NOT mean warm floors on the main floor.   In fact, I don't know if attributes to any warmth upstairs as radiant heat does not rise, hot air does. the closer to the slab the warmer. 

I'm doing a little experiment. I was keeping my basement at 69 degrees.  Yesterday I pushed it up to 72.  It took a lot of wood to move the 3000sq ft basement up just 3 degrees.  I measured my main floor drywall temperature at 66 degrees yesterday which is about what we keep the main floor at.  I will give it a week and take the temp of the drywall and see if it raises any.  The slab temp of the basement needs to be apprx 78-80 in order to keep the basement thermostat (4.5' above the slab) at 72. 


For me the jury is still out.

[D2082]

The basement will be unfinished and is approx 2800 sq ft.  I had been wondering how much, if any, it would contribute to the main level heat.  There will be no bat insulation in the floor joist above, only R10 on the basement walls (per my county's building code).  My builder had mentioned that it would be pre - zoned in the slab incase we ever finished any of the basement in the future.  I believe it will also have a shutoff so that we could cut off the entire basement lines if needed (?) I will ask and confirm that.  Thanks for the info. That is good to know. 

[caper]

wow, so that would mean your entire home is almost 6000 sq ft, well I hope your furnace is a 10,000 unit, I would insulate the walls more and I hope your putting foam in your under your slab.....if so you shouldn't have any issues, I have radiant heat in my basement approx. 1800 sq feet, heats no problem and the floor only calls for heat every two days or so, just make sure the water temp is only set for approx. 120 degrees, just my two cents worth,however there is a lot of heat smart guys on this forum, so stay in tuned...

[D2082]

Thanks Constable.  Yes the main floor is about 2800 sq ft with the full unfinished basement being the same.  I put R5 insulation on top of the gravel and plastic and placed the pex in PVC in case of any leaks so I wouldn't have to jackhammer up my basement slab to fix.  Ill have access panels to be able to replace the pex should I ever have to.  My dealer says it may take a little longer to come to temperature being in the conduit but once there it shouldn't take much to keep it there. I upgraded to the H25 from the H5 I was going to purchase once I decided to run through the slab. It's a chunk to bite off at once but I'm hoping the investment will pay off.  I will keep the 120 degree figure in mind, thanks that's helpful. 

[Sluggo]

You ran your infloor heat tubing thru conduit???  And only r5 under the concrete???  We put in about 200 basements a year and I've never heard of such a thing.  Put pressure on the lines before you pour the floor and then you know if and when you hit a line.  Of the thousands of basements we've poured we only once cut thru a tube.  That was when we were cutting the control joint.  I wonder how efficient your infloor heat will be with conduit around it?

[D2082]

That's correct.  Pex inside of 1.25" pvc, so that expansion and contraction can occur. R5 is all the insulation required.  Have you heard of any of those basements leaking from expanding lines against concrete?  How deep do you put your pex from concrete surface?  Always curious to learn from other's experience. 

[aries9245]

I have to agree with Slluggo.. On this we also pour many basements and installed pex lines under the slab but have never heard of putting pex in pvc..pipe ? Is this something the heating contractor told you to do ? Not trying to insulte you I just never heard of doing it like that

[Sluggo]

Never had one leak.  We grade the floor out depending on floor thickness,compact,lay r10 Dow board down over 6 mil poly then staple our lines to that.  So it's under 3,4,5" of concrete depending on floor specs.  Every once in a while we get a customer who reads to much on the Internet and wants it suspended in the concrete,say 2" under it and 2" over it.  What they do in Europe is grade the floor,Dow board and lines,then put 8" of sand over that and then the concrete.  This is probably the best way to do it by creating a larger thermal mass.

[D2082]

Sounds like a good plan.  More than 1 way to skin a cat, I guess.  I'll be sure to report back once the system is hooked up and running. 

[yotehunter66]

Welcome to the site.

[D2082]

Thanks yotehunter.  Appreciate it.  Really learning a lot so far.