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Problems with radiant heat leaking in ranch on a cement slab


My mother-in-law has radiant heat in a ranch build on a cement slab. Of the seven zones, one has ruptured a has been shut off. Since the house is a ranch, I was thinking that an HVAC person could remove the boiler and install a furnace and pipe all of the duct work through the empty attic. This way, central a/c could be added to the system at the same time.

The house is in mass, so I was also thinking of converting from oil to natural gas. Gas is on the street. The furnace that national grid sells is American standard. I'm still in the process of finding reviews on it.

Any body have thoughts on this. Any help would be appreciated.


Re: Problems with radiant heat leaking in ranch on a cement slab

When it is working properly, there is no more comfortable and efficient heat source than radiant in the floor. If your feet are warm, you are comfortable. It is quiet and doesn't have the peaks and valleys of hot air furnaces. Have you looked into having the bad circuit fixed?

You are contemplating a lot of new furnace hardware and expence to run the ducts through the attic. I assume the attic is not conditioned. The ducts would have to be extremely well insulated and sealed to deal with the hot/cold, humid swings in the attic.

Heat ducts in the ceiling with now cold cement floors is not an ideal situation, although, it it is great for A/C in the summer.

Perhaps a good compromise would to leave the existing working system alone, or perhaps just upgrade the boiler to gas, and then heat/cool the now heatless section of the house with a split system. These are small heat pump systems with the condenser outside , as with a normal heat pump, but with a small conditioning unit hanging on the wall. With these systems, the areas can be separated and have their own thermostats. This might be highly advantageous if the rooms without heat are the bedrooms.

Some of these split systems are now very efficient. They have been popular in other parts of the world, largely for their flexibility.

Re: Problems with radiant heat leaking in ranch on a cement slab


Thanks for the comments. I'm afraid that other loops will start to leak. The house and system are from the 40's or 50's. Just not sure how long they are designed to last from that era. The boiler is old and has been giving her trouble, so I thought that the best solution would be to get rid of the old boiler. Not that there is a clean slate, I thought that the advantage of getting central ac would be a huge plus for her.

The floors also need to be redone, so there is an opportunity of insulating the floor a bit before putting down the final product. Mostly pretty old carpet.

Yes, her attic is unconditioned. I have ac duct work in the attic. It is sealed pretty good and recently insulated better than when it was installed. It seems pretty good to me, but what do I know. Definitely cools the second floor pretty well.

Thanks again.

Re: Problems with radiant heat leaking in ranch on a cement slab


How nice of you to help out your mother in law with a problem that must be causing her a lot of anguish!

1) Given the various issues contained in your mother in law's heating problem, I think your best bet is to consult the Yellow Pages under "Heating Contractors" (make sure you ask them over the phone if they are experienced in fixing a slab radiant heating system) and have at least 2 or 3 technicians experienced in slab radiant heat come over the house to inspect the damage & make some recommendations as to whether the problem can be fixed at a reasonable cost, or some other system installed--the break in only one of the 7 zones may have been caused by a minor problem such as a failed circulator pump, or a stuck valve that prevented the water from circulating & perhaps no non-toxic antifreeze (propylene glycol) was put into the system to prevent the pipe from freezing, resulting in a burst pipe (please have the antifreeze installed ASAP, so no further damage occurs--propylene glycol is available at Home Depot, Lowe's & plumbing/heating supply outlets); any heating technician can install it for you.

2) There is a way to install a radiant zone ABOVE the slab if the break in the slab cannot be accessed--this would be less expensive than planning for a completely new system---especially in January---limp thru the winter with what you have now & make any changes in the spring after the freeze danger passes---the radiant technicians have tools & a way to locate the tube break in the slab & go in & fix it.

3) After you have 2 or 3 heating contractors over the house to give you their suggestions, you will be in a much better position to evaluate this situation & decide which way is the best (and least expensive) way to go.

4) It often takes months to schedule & have done a project by the gas co.-----they also can't work in most winter weather---just to open the street they have to use a backhoe to dig up the street & make the connection & install a gas line to the front of your house which costs approx. $1,000; then there's the extra cost of installing an outside gas meter, extending the line from the house front to inside the house, & connecting to a new gas boiler/furnace, or a conversion-type burner that fits inside the present oil boiler-----that's why I think you should collect & evaluate all the info on this now & wait till the spring to have the work actually done.

5) You DO NOT have to buy the gas boiler/furnace from the gas co.; nor do you have to have the gas co. extend the gas lines from the front of the house to inside the cellar----you can call any heating contractors in your area for competitive quotes as the best (and least expensive) way to go on this aspect of the install.

Re: Problems with radiant heat leaking in ranch on a cement slab


this is exactly what I am doing, getting information. The leak has been there for years and the boiler problems are fairly new. I'm here collecting free advice. There is no basement so that is a huge problem. She is on a corner/wedge shape lot so getting the gas to the house would be easier and more direct from the back street. I think it would be less digging around her property. The gas company won't start anything until April, so I do have time to get some contractors in for some estimates. Great idea!

i appreciate the time you spent with your reply.

Thank you

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