How crutial is radiant in floor heating in the basement?

geboy

Hello all!

So long story short my wife and I are building a new (standard run of the mill) house in a development. My cousin said we should install radiant hydronic floor heating in the basement before they pour the concrete, cause thats the most cost effective way to install it, and provides the best bang for the buck. I didnt even consider it, and my contractor never mentioned it, so I just figured it was out of my budget. Well, my cousin insisted that it is pretty straight forward and the supplies are reasonably priced as far as the tubing and manifold are concerned. So I investigated it, and sure enough I have delved countless hours of research and reading into this idea of radiant floor heat. YES I did find radiantech and read all the back and forth with customers and professionals, and the discrepancies attached to that subject.
So basically this is where I'm at. My basement floor is being poured at the end of this month, and I've tried talking to my contractor about having either myself, or some hvac company JUST LAY THE PEX TUBING down before they pour, so it is there in case I ever want to hook up a heat source to it.
My question to you guys and gals is. How effective is having radiant in floor heating (properly installed) in the slab in my basement??????? Is it going help heat the rest of the house???????? Or is it just going to be an overly expensive way to justify spending a lot of time down in the basement? My cousin insists that basement in floor heating has helped keep his house a good comfy temp. He even initially ran pre-tubing under his 1st floor cause he was going to run radiant under his first floor also, but said that he never bothered cause the basement heat did a good enough job keeping the house at a good enough temp.
I'm just feakin out at this point cause I'm running out of time, and the hvac guy my contractor deals with has basically been trying to talk me out of it, saying that its expensive to install, and costs a lot of money to run and is totally pointless having radiant down in the basement?!?!?!
Please someone help!!! I just need some guidance from some pro's who know this stuff like that back of their hand. It appears my local hvac people are noobs!

Oh, BTW. House is a 2400sq, 2 floor, with 9' basement and 1st floor ceilings, and I am planning on finishing the basement, and the house will have 2 zone heat pumps.

Thanks!

JUGHNE

We have a heated floor in the basement. I believe it is the main heat source for the house. We know when it is been off for a length of time. We heat out master bathroom and my office which are on opposite ends of a house the size of yours.
The rest of the house is not heated and comfortable.
We have a 560 sq ft sun room which has floor heat which seldom needs to run.
The 1000 sq ft attached garage maintains about 50 degrees with no heat other than thru the basement wall on one side of it.

The basement floor heat makes that area livable and comfortable. We have painted concrete floors down there and can walk around barefoot.

It makes heat pump heat seem like milktoast by comparison.
What fuel would the boiler burn?

Your HVAC people just don't want to learn about anything outside the box. Where are you located?

geboy

I'm located in PA, near the Lehigh valley. I'm not sure exactly what the heat source would be, cause I have conflicting info, but I am getting a 1000gal LP tank in the ground, so propane should be plentiful.

Harvey Ramer

You only get one chance to put tubing in concrete. If you can afford it, do it.

Harvey Ramer

Just make sure you have 2" of Styrofoam under the slab and at least 1" of foam around the edge of the slab to keep the heat from conducting into the concrete wall. I wouldn't build a house without putting it in.

Gordy

I will add your hvac guy doesn't know what he is talking about in his assumptions about RFH.

KC_Jones

If you have to talk the HVAC guy into doing it and he has a negative opinion of it, I would suggest getting a new HVAC guy. If that is his attitude he doesn't know anything about it and if he does end up doing it will probably do it wrong. There are a lot of little details to get right and you will be very disappointed if it isn't done right. Those are probably the installs he has seen or done, the ones that don't perform properly.

hot_rod

Some builders install radiant in the basements of all the homes they build under the "Radiant Ready" concept, a selling feature over competitors.

If you plan on spending time in the basement inn the future there in no better or more comfortable way to heat a concrete slab.

It is not a tough DIY project, do a load calculation to get tube spacing and lengths.

While the basement will not heat the upper portion, it will lessen the heat load on the upper parts by keeping the basement area warmer. Heat goes to cold.

Some other radiant myths dispelled here, thanks to healthy heating.com

http://www.healthyheating.com/Radiant_Mythology/Radiant_Mythology.htm#.WHDrl7GZO7Y.

geboy

Thanks everyone for your input. The frustrating part is the hvac guy says he has it on his house and uses it primarily for heating his whole house. The only positive he says about radiant is the comfort level, but he kept talking about how expensive it is for him to run. He also said that he likes to crank it up cause he likes the feeling of warm floors??? I thought that radiant did necessary heat the floor to warm feeling, more or less just not cool. Anyway he says he installed it like 13 years ago in his house. Maybe he has no clue how that crap works. He said that he installed it in a 9000sq house and it cost the owners 190k to install, and that wasn't enough money to do the job???
I am currently getting a quote from another hvac company, but I'm not super confident in them either. All the hvac people around my area seem to either be crooks, or can't seem to fix/install anything right. I wish there was a radiant pro near me.
I also asked my builder if I could just install the tubing before the pour, and he kinda fround on that.
Uhh, I'm so frustrated! This shouldn't be so difficult! But all the (experts) in my area seem to quiver at that thought of it.

Dave H_2

There is also your expectation of the RFH in the basement as in do you expect to feel warm,cozy floors when you are down there to make your toes toasty warm or just to heat the space?
Finishing the space, leaving some storage area but do you know the exact layout so that you don't heat the space you dont want heated....

I say this as to not discourage you from RFH, but the floor is not the only option to get RFH.

The basement has a very low heat load so therefore it is not going to require a high water temperature to heat it, you also won't feel it on your toes, especially if you carpet the space (which most do when finishing that space)
If you are not sure of the layout, it can be difficult to zone the space.

I have had both radiant floors and radiant ceiling/wall in my basement. While the floor was nice to have, it did add extra expense to the project, but I got the same feeling from the the ceiling or wall option.

Dave H.

hot_rod

I have had both radiant floors and radiant ceiling/wall in my basement. While the floor was nice to have, it did add extra expense to the project, but I got the same feeling from the the ceiling or wall option.


Dave, how much cheaper is a radiant ceiling compared to a slab, since the slab cost is already in the budget?

I would say materials and labor will be higher to do a radiant ceiling? If good quality transfer plates are used, especially.

The point is the slab is already part of the project, adding insulation and tube should not throw an "expert" for a loop. Pun intended.

geboy

Dave, to add to your comment. Now excuse me if this is a total noob question. Let's just say I heat the ceiling with RFH, to heat the basement. Would that be the same install procedure for installing RFH in the 1st floor, just with no insulation under the tubing?

Mad Dog_2

Worth every penny...the kids and cats LIVE down there in the winter. Mad Dog

Dave H_2

It is the expense of the insulation and maybe removing base to allow for the thickness of the insulation and then the proper thickness of the slab on top. Depends on where the level is already at and how thick a floor is planned. Being that time is getting close and decisions need to be made.......maybe the floor is not the best choice at the moment. Will it cost more to do a wall/ceiling compared to getting in the slab? Maybe, maybe not
I have worked on plenty of radiant walls for a basement space, you still get a radiantly heated space which is still the best a far as I am concerned.

Sometimes ya just gotta say "Design the radiant to fit the space, don't change the space to get the radiant" So if a radiant floor is not in the cards today, radiant walls/ceiling can easily be done tomorrow.

So thats the decision that needs to be made, @geboy if you can do the slab and it doesn't throw too much off, go for it!

And no, you cannot have a radiant ceiling for the basement AND have a radiant floor for the first floor. You can't steal form Paul to pay Mary!

Dave H.

Gooch

The biggest expense in a radiant slab is imo the insulation under the slab. I am baffled with all the insulation requirements for new construction that under slab insulation isn't required regardless of rfh or not.

Gordy

I can tell you a neutral floor temp is far superior to a chilled one.

74 verses 68 is a huge difference to bare feet.

jumper

I suggest no insulation under radiant slab. Over the decades soil underneath will warm up. Then when there's no electricity for weeks -happened in Toronto a few years ago- your family can comfortably sleep on basement floor. And your house,dark&cold,won't freeze.

Gordy

It's about getting as much of the energy you pay for into the space you need it.

However @jumper plenty of radiant slabs out there of old with no insulation that work, and still work. I do agree having that stored thermal mass can help in a pinch.

Paul Pollets

R10 is required under a radiant slab, as well as perimeter insulation. It's in most building codes and makes a large difference.

hot_rod

One of the major radiant manufacturer use to promote perimeter only insulation, leaving the center portion un-insulates, mainly on large commercial slab. The motivation was cost reduction, of course. Trying to compete with unit heater bids!

Huge mistake! It made for long start up and excessive energy consumption. Knowing what we know now, I would advise against un-insulated slab, anywhere. If the cost of adequate insulation is the deal breaker, I'd walk away from the job.

Same with the bubble foil options. Some reps and dealers still promote that, SAD

Zman

jumper said:

I suggest no insulation under radiant slab. Over the decades soil underneath will warm up. Then when there's no electricity for weeks -happened in Toronto a few years ago- your family can comfortably sleep on basement floor. And your house,dark&cold,won't freeze.

@jumper
Are you serious?
If you are trying to maintain a slab temp above 70 degrees and the earth in your area is in the 50 degree range, you will never heat the core of the earth an "store" the heat. You will just constantly be wasting energy to the ground. Sure some of the ground will warm up, thermal equilibrium is a hard thing to fight without insulation.
In other news, heat does not rise, double bubble does not work....

jumper

Zman,I told you what happened in Toronto. Without that thermal mass accumulated over decades,the family would have had to move somewhere. They might have have had to drain their system! And their plumbing. On second thought,an emergency generator may make more sense than warming the earth beneath one's basement.

And on third thought,industrial facilities used to use off-peak electricity to store heat in earth beneath slab.

geboy

Ok, so here is where I'm at currently. Concrete is being poured in 2 WEEKS!!! And my contractor keeps telling me that this whole in floor heat thing is just a waist of money, blah blah blah. But he said it is ultimately your decision.
So, next thing to figure out. everything is set as far as fill and what not, they are just waiting for the roof to go on so they can pour the concrete. If I go with crete-heat insulation panels, they are claimed to be 2 7/8th thick. So this will basically raise the floor about 3"??? I said this to my contractor and he was not thrilled about hearing that.
So, I guess the next question is. Is there another insulation that would work good under the slab, but wont raise the floor more than a 1"? I would like to keep the floor at relatively the same height, but I need insulation under the slab and around the parameter. I am concerned about installing the tubing without having insulation under the slab.
Also, I just read about the importance of having the tubing not at the bottom of the slab. Wouldn't crete-heat keep the tubing at the bottom of the slab?
FYI, My slab is going to be 4"

Thanks

hot_rod

Who is your contractor working for? You should be able to get what you want in your home. And he may learn some new tricks.

You mentioned a 9' ceiling height in the basement, so that 3" should not be a deal breaker.

Yes the pre-formed insulation panels do hold he tube down at the bottom, not ideal, but worth the trade off of trying to lift mesh and tube as you pour. That doesn't always come out well, especially if the concrete guys are anti radiant

IF you go radiant in the slab, I would not go below that Crete-Heat as far as insulation thickness.

It is a user friendly product for one timers.

It is critical that they rake the subgrade well or the panels will crack and you get an uneven slab thickness.

Gordy

Is "your contractor " doing the concrete work, or is it his sub contractor?

Abracadabra

i'm thinking the concrete contractor has experienced working with tube on a pour before and doesn't want to deal with the liability of damaging it

geboy

It is a sub contractor doing the concrete.

So basically 3" of insulation is what I would need, regardless of type?

Also, isn't it odd that your concrete floor will be technically "floating" on top of insulation foam??? This just popped into my head

Canucker

geboy said:

It is a sub contractor doing the concrete.



So basically 3" of insulation is what I would need, regardless of type?



Also, isn't it odd that your concrete floor will be technically "floating" on top of insulation foam??? This just popped into my head

No, that's how it's done when you're installing a thermal break for a concrete floor. It sits on top of the foam insulation, like a bathtub, if the sides are done too.

hot_rod

geboy said:

It is a sub contractor doing the concrete.



So basically 3" of insulation is what I would need, regardless of type?



Also, isn't it odd that your concrete floor will be technically "floating" on top of insulation foam??? This just popped into my head

In a basement, I think 2" would be adequate.

You could buy 4x8 sheets of 2" thick DowBoard and either foam staple the tube, or install a mesh then tie the tube to the mesh.

Once you do that and install a vapor barrier you may as well use the Crete-Heate. It is the insulation, hold down and vapor barrier in one easy to install system.

Are they planning on installing the mesh in the slab anyways? if so that takes on step out of your task.

geboy

I'm not sure if they use the wire mesh or not. What is the point exactly of the wire mesh?

Gordy

Usually in residential no wire mesh is used unless requested. Mesh will not prevent cracking. However if done correctly it will prevent adjacent sides of a crack from deviating from its plane.

Use fiber mesh if slick finish is not a deal breaker, or pins instead on f mesh. Mesh is going to create issues if this concrete guy has not done radiant.

hot_rod

Remesh, for radiant contractors serves one purpose, it holds the tube down and at the correct spacing Nobody likes walking across mesh as they pour out.

Plenty of debate on whether it adds any crack protection or crack control in slabs. Certainly at the very bottom of the pour it doesn't add much value. Like rebar it needs to be surrounded by concrete.

Fiber mesh is common around here and if they use a power trowel, they can burn off any fibers that stick through,so it doesn't look like dog hair across the slab.

A power trowel may not be in the plan for a small basement job, especially if it is already housed over.

Gordy

Using pins instead of fiber gives like results for strength, and is power troweled finish friendly. One draw back to pins is rust spots in a damp unsealed environment. Concrete sealer helps prevent that.

Zman

2" Insulation should be adequate. It is unfortunate that the contractor did not prep the slab for insulation. It really should be insulated regardless of in floor heat.

Ideally the tubing should be centered in the slab. Good luck with that one. The concrete guys may well kill you .

The only time I have realized the dream of centered tubing, I convinced the structural engineer to spec rebar on chairs. Then you just sympathize with the concrete guy and blame the engineer. It does cost more money.

ChrisJ

Gordy said:

I can tell you a neutral floor temp is far superior to a chilled one.

74 verses 68 is a huge difference to bare feet.

Na.
My 38-40° kitchen floor is perfectly comfortable, I never complain about it, right @KC_Jones ?


In all seriousness to the OP, please be sure who you hire to do this knows exactly what they are doing and has a good rep. We see too many concrete jobs with new pex either leaking, or simply not producing enough heat and it turns into a complete disaster. What are you going to do, jack hammer the entire floor out and start over?

When done right, it's the best heat money can buy.
When done wrong, it's money down the toilet.

It's good you're doing the research. If you understand what needs to be done and how it needs to be done you can keep an eye on things.

Gordy

ChrisJ said:

Gordy said:

I can tell you a neutral floor temp is far superior to a chilled one.

74 verses 68 is a huge difference to bare feet.

Na.
My 38-40° kitchen floor is perfectly comfortable, I never complain about it, right @KC_Jones ?


In all seriousness to the OP, please be sure who you hire to do this knows exactly what they are doing and has a good rep. We see too many concrete jobs with new pex either leaking, or simply not producing enough heat and it turns into a complete disaster. What are you going to do, jack hammer the entire floor out and start over?

When done right, it's the best heat money can buy.
When done wrong, it's money down the toilet.

It's good you're doing the research. If you understand what needs to be done and how it needs to be done you can keep an eye on things.

I think I would move the kitchen, and make that room the meat locker.......

Gordy

You could throw some radiant in there. It is the best heat money can buy. If done correctly with a loop off the titanic in the basement

hot_rod

Who is doing the actual tube installation? You, the builder, concrete guys, plumber?

geboy

Me and my cousin's husband who builds houses and has installed radiant multiple times.
So I finally got my contractor on board with it. He is going let me and this guy go in and install the tubing. I'm thinking of just going with the Crete heat just to make things easier for us.
My contractor said that the concrete guys run some 1" foam board around the perimeter before they pour. I asked if it was insulation board or some other stuff. He said that it basically provides a thermal break and helps to keep leaks from running onto the slab. He says it's an old school method, but he still does it. Is that 1" foam board going to be enough for insulating the perimeter? Or should I ask them to get a thicker board?

ChrisJ

geboy said:

Me and my cousin's husband who builds houses and has installed radiant multiple times.

So I finally got my contractor on board with it. He is going let me and this guy go in and install the tubing. I'm thinking of just going with the Crete heat just to make things easier for us.

My contractor said that the concrete guys run some 1" foam board around the perimeter before they pour. I asked if it was insulation board or some other stuff. He said that it basically provides a thermal break and helps to keep leaks from running onto the slab. He says it's an old school method, but he still does it. Is that 1" foam board going to be enough for insulating the perimeter? Or should I ask them to get a thicker board?

Please,
Take a lot of pictures and post them here before that pour,just for good measure.

hot_rod

That edge insulation is a tricky detail in a basement slab. It should sit on the footing and be the same dimension as the slab thickness.

Thicker is better, but you see the exposed foam around the entire slab. sometimes a 45° bevel is ripped on the top of the edge insulation so you don't see that exposed 1 or 2".

I found a dap of foam adhesive every 12" helps keep the edge insulation in place so the finishers has a good edge to screed to.

It takes some time and patience to get the small details, but the pour will go much smoother if you get it right before the mud flows. Hard to make corrections once the trucks start dumping.

Is this going to be pumped or are the wheeling the mud around, if the house is framed already? Wheelbarrows or Georgia buggy add another challenge to radiant pours.

An air test is a must, so plan on manifolding all the loops together.