Radiant under Kitchen Cabinets?

Constantin

As I don't have Dans book handy, I thought I'd bring my question to the well/wall of wisdom...

IIRC, I thought it was a no-no to install radiant heat under kitchen cabinets that will contain foods... or refrigerators. Yet, that is what I see my installer did today. It's still an easy fix, so what do I do?

From the other left field comes the following question: Has anyone installed a vent for AC under fridges to "help" them? Cheers!

Jim waide

Pantry as well?

Along with kitchen cabinets,what about a pantry with shelves of food. Wondering how to do mine.Basically a long narrow closet(10 ft by 4 1/2 ft.)outside wall and with it`s own entry door.Sounds like to much area to skip putting radiant under it,but worried it will stay cold with the door shut and an outside wall. Thoughts?

hr

I still feel

IF the cabinets are on outside walls you should have at least one loop of radiant under them. Especially if the kitchen sink is in an outside wall cabinet! Need to protect the water supplies and lines to the dishwasher.

Is the tube installed on top or below the floor? Slab? Pretty easy to reduce heat output by moving the tube away from the floor if installed below.

Some guys wrap pipe insulation on radiant loops as they run down interior hallways in slab radiant to prevent overheating a small interior space.

Often times kitchens need all the loops you can get in the floor space if they have outside walls. Look at the heat loss calc and determine the heat flux for that room before you remove any tube.

hot rod

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Weezbo

Listen to Hot Rod on that one.

on an outside wall...protect the plumbing...

Carl PE

agreed.

My house had electric radiant in the ceiling. Guess what froze while it was sitting vacant before I bought it..

Now, how exactly is the heating guy supposed to know which cabinets are going to have food in them? Will the next owner keep his potatos in the same spot? I'd put the tube under all the exterior cabinets, and keep the perishables somewhere else.

Regarding the fridge, I wouldn't put tubing under it. It generates heat on it's own.

I like the a/c vent idea, but I'm skeptical of how much overlap you'd get in the run times..

Unknown

ever smelled a kitchen garbage pail under the sink with radiant there?

We avoid cabinets like the plague and have never even begun to have a freeze-up issue because of it. The radiant is at most 2 feet away from the plumbing under the cabinets. Some heat gets there, certainly enough to prevent a freeze concern. You don't want to cook the garbage or take any unnecessary puncture risks and the heat isn't too helpful under there anyway.

Balancing it out, I don't see a compelling arguement to heat cabinets. If you can't meet the heat load with the exposed amount of floor, I wouldn't count on heat gain from the cabinets to make up the difference.

As for pantries, we usually put them on their own loop if possible to allow it to be cranked down in flow relative to the rest of the zone. A lot depends on the PSF heat load differential between the pantry and the rest of the zone as to how to handle it if it's a very small space.



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Weezbo

i belive .....:)

the interior partitions and the floor will keep the stair way size pantry warm... if you have a good vapor barrier no window in it and have insulated the exterior wall and the home has no piping running in that room other than a supply air from a hrv you would likely not even discerne any temp diff at all.

Carl PE

eeew!

I hadn't thought about the garbage. Do you have one of those slide-out things?

I keep mine outside the back door.

How about radiant countertops?

John MacGregor

Cabinet heat

Have you always heated your kitchen cabinets? Have you put or seen standing radiaters in kitchen cabinets? Did you put baseboard heat in your cabinets before you started radiant panel heat? Do you put ductwork into your cabinets (assuming you have the ability to also do sheetmetal)? You probably never have done any of the above, so why start now? As Tom Silva said, "I thought a heated countertop was a good idea, until the butter melted".

Barry E. LaDuke

Aren't we talking about really low temperatures here?

If the floor surface area is a maximum of 85 degrees for only the highest heat loads, and given the reduction of temperature as it makes its way along the conductive path of the cabinets, is it really that big a concern to have heat under the cabinets?

Also doesn't heat flow slow down when the delta T is smaller (like it would be in a cabinet area) so the majority of the heat would just continue on its merry way to an area (outside the cabinetry) with a higher delta T?

Finally, don't the cabinets actually become low level contributors to the heat replacement (albeit at lower temps than the floor surface), thereby aiding the floor in replacing the heat.

It appears to me to be no great risk and some small benefit to heat under cabinets; and no great benefit and some reduction of system performance to keep tubing out from under them.

Barry E. LaDuke

hr

Seen all of those John

Hydronic kickspace heaters are real common in kitchens as very little outside wall is available for BB installs..

Around here FA guys install vents under the cabinets also. Same reason, not a lot of options for heating a kitchen with cabinets on outside walls.

In all the years I have installed radiant I have never had an overheat problem with one loop of tube under the cabinets. That 4" kickspace air gap makes for a good insulator!

If worried about it install a piece of 1" foam under the cabinet, or in the cabinet base for that matter, with the garbage stored in it.

I agree 85 floor temperaturer under a 4" air gap doesn't transfer a lot of heat.

Show me otherwise.

I'd rather install the tube and deal with a small if any overheat than not have it in there. Hard to install after the fact

hot rod

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Unknown

with all these points you're making about how negligable the heating is, it makes me wonder what the point of that one loop is then

I think it's safe to say it doesn't really matter a whole lot either way and it's a matter of preference more than anything.

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hr

Rob

when you do a design and heat load for a kitchen do you use the actual room dimension or the un-encumbered space. Divide the two to get the heat flux # and many times you will find the "available" floor space will not meet the load without high floor surface temperatures.

Two outside walls with an L shaped counter, on those outside walls, and an island in the middle will really throw you a curve. Could be left with as little as 30 square feet of floor space to meet that load with.

One loop under cabinets at least put some heat at the spot where the loss is the greatest, the outside wall!

With a 0° outside temperature and 80° floor temperature pretty clear which way, and how fast, the heat will travel. Even with an insulation layer in the wall. Heat goes to cold ALWAYS, and the rate of travel is driven by the delta T.

I have seen more than one kitchen sink with frozen water supply lines in my years in the heating business. I'd rather opt on the safe side. Frozen and split pipes make much more of a mess than warm garbage

Just like an employee, it is easier to simmer one down than fire one up

hot rod

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Unknown

I'm quite familiar with heat loss methodology HR. I know exactly what you are talking about and while it's not a situation I run into a lot personally since it seems most kitchens are wide open to dining rooms or other spaces, I have seen kitchens that cannot meet load. *EDIT: cannot meet load with the available floor space, that is.

I for one would not trust a single loop of tube under a cabinet to allow an otherwise marginal floor to "make it". I would advise supplemental heat, and that would be that. One loop under a cabinet is pretty much a waste of time, has a few issues with tubing safety, and the garbage issue .

I'm not going to throw my hands up and say well you can't heat your kitchen, and I'm not going to throw a loop of tubing under a cabinet and say PRESTO MAY THY KITCHEN BE THUS WARMED. I'll do what needs to be done to meet the load.

Heat does always go to cold. It's how long it takes to do it that is the issue, and installing tubing under a cabinet doesn't set you up for a very favorable circumstance for the rate of heat transfer. At least, not at the water temps I like to design to.

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Weezbo

> with all these points you're making about how

> negligable the heating is, it makes me wonder

> what the point of that one loop is then

>

> I

> think it's safe to say it doesn't really matter a

> whole lot either way and it's a matter of

> preference more than anything.

>

> _A

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> 340&Step=30"_To Learn More About This

> Professional, Click Here to Visit Their Ad in

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Weezbo

> with all these points you're making about how

> negligable the heating is, it makes me wonder

> what the point of that one loop is then

>

> I

> think it's safe to say it doesn't really matter a

> whole lot either way and it's a matter of

> preference more than anything.

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 340&Step=30"_To Learn More About This

> Professional, Click Here to Visit Their Ad in

> "Find A Professional"_/A_

hr

Guess we will disagree Rob

Having personally install and watched hundreds, maybe closing in on a thousand installs dating back to the 80's vintage PB systems I feel I have a pretty good idea of what works.

Not sure how many systems you personally install and get back to. Or how may systems you troubleshoot and repair installed by inexperienced installers, but...

Trust me fellow wallies one loop of pex under a cabinet, on an exterior, wall is NOT a waste of time : Buyer beware

hot rod

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Unknown

Not an installer, but I've designed many hundreds of systems and helped troubleshoot more than a few. The only cold cabinet complaint I've ever seen was a high wall cabinet, one time, which a floor loop wouldn't help anyway. I guess I need to start specifying radiant wall behind those now? we never spec tubing under cabinets and oddly enough, the kitchens heat just fine.. but it's not odd, actually, since I know whether it will or it won't before our client does the install.

thus my original comment. it's not a big deal either way, and it's a matter of preference. puncture risk is small but so is the likely heat output.

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hr

Rob, I don't mean to

challange your design skills. I'm sure your customer enjoy a warm comfortable system. That's good for all of us

I do think it benefits all when designers and installers add, and share, their experiences and question the how and whys. I just throw out options and explanations based on my experience.


Don't mean to come across as a know it all, even though I live on Know it all lane! (named after my wife and mother in law)

hot rod

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Unknown

no worries HR, this is one of those reoccurring debates that has been going on since the first kitchen had radiant put into it probably.

If I see you at ISHNA, I'll be sure to high five you for all the great work you do for radiant everywhere

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Gordy_2

I do not mean to intervene in a perfectly healthy arguement. But an important variable, I feel has been missed. What is going on in the floor below the kitchen? Is the kitchen over a conditioned basement,is the kitchen on a slab,is it over an unconditioned crawl space? Latent heat can account for alot. Both of you are right depending on the scenerio.

Unknown

also

for what it's worth, if you can demonstrate a significant heat output in this situation, I'll happily eat my words and join your camp. I just can't swallow it based on the airspace arguement you just used to show that heated garbage wouldn't be a problem... which I've seen actually be a problem on some other's jobs.

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Bob Gagnon plumbing and heating

Hot rod is right

I have been running a loop of pex under the cabinets with no complaints or problems. I can't tell you how much they put out, but when it's real cold a warm cabinet is better than a cold one. one customer told me their radiant countertops ripened fruit too quickly. I asked them if they wanted me to shut off that loop and they said NO WAY! Put radiant everywhere. Bob

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Carl PE

Maybe

perhaps they could just take the garbage out when (or possibly before) it starts to stink..

just a thought.

hr

Anothe common occurance

if the homeowner decided to remodel and shuffle cabinet locations or add onto the kitchen. Leaving a path of unheated area would be noticed. And of course hard to correct on a slab or an area with finished space below. Just another thought.

hot rod

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hr

Anothe common occurance

if the homeowner decided to remodel and shuffle cabinet locations or add onto the kitchen. Leaving a path of unheated area would be noticed. And of course hard to correct on a slab or an area with finished space below. Just another thought.

hot rod

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Unknown

Now that is a very good point right there.

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Gordy_2

Go with ceiling radiant then there is no issue. Dishes go in the uppers so they will be warm for supper.

Weezbo

Did you consider castration?

i think there is a benifit to heat under the floors in the home when using copper fin baseboard(convectors)..so when i install radiant i put a run under the cabinets near the water lines. You dont have to do anything septs pay taxes and die.my thought is that i have also fixed a great many frozen houses...for whatever the reason homes with perimeter heating and heat under the floors in front of the cabinets and heat under the sliding glass doors or entrance doors or radiant floors with a run under the kitchen cabinets have todate not been something that ive had to fix....toe kickers etc i have had the luxury of r&r ing or replacing frozen or cracked fittings. so it is my basic stradgey when installing radiant to run a line under the cabinets near the water lines...and will continue to do so.it is the only place on my radiant the tubing doesnt have a partner ,the other line i drag out around the block outs about 5 " all the way around and bring them back again on the next perimiter wall...it does get appreciably colder around here... and thats my story and im sticking to it:)