early 1900 in floor heater

I have a inspection tomorrow on a home from early 1900 and I believe it has an old in floor heater. I have not yet inspected this type of heater so my questions are below.

Question 1: Any pointers on specific things to look for?

Question 2: Any one know of websites to go to for research?

Thanks Dan

The majority of the older homes here have them installed. They are called floor furnaces. I have never seen one that works. They have all been long replaced with central units. Since they are only installed in pier & beam homes the one thing I always check is that the gas line to them has been disconnected. Sure this does not help much with your question but it is something you can check if you find abandoned ones.

Hi there,

I agree with Peter, I see them once in a blue moonand have never seen one working. If the one you are viewing is still operational then I would check for evidence of service record and report that the furnace be serviced prior to closing.

The attached image is of the last one I saw, with its protective grate removed. I recomended its removal.



I have inspected one operational unit. It is kind of like inspecting a big furnace without the blower. Check for proper air and fuel supply and proper venting. Check the thermostat, look for corrosion, etc…

Sorry, I took a picture, but it’s not very good, so I won’t bother posting.

If I run into unusual heating systems, I look them over, but always state that it’s unusual and my experience with them are limited. Then state that further inspection by someone <b>with experience</B> with the systems be considered. With some systems however, the concept is simple enough that I don’t recommend having it inspected, just for them to make sure there is someone in the area with experience servicing the units.

Am I correct to assume that there is no duct work for this type of system? The heat is supposed to just rise to upper floors by itself?

Yes, thats basicaly it, as you can guess they are very inefficient, being little more than a gas burner in a very rudimentary heat exchanger.



Ive seen 2 last year in use. Both propane-both worked, but no service record, I called them out for service check and advised both clients they would be inadaquate in outlying rooms and when they failed it would be difficult to impossible to repair. NOt only that but both clients has small children and those grate covers get hot! Yup, I shoulda removed the cover before I turned it on***.:frowning: ***Once you shut doors, you have no heat. Both places were built in 1910-1920.
They are pretty simple to inspect, as others have said. I can’t find pics right now,but I think you’ll figure it out real quick once you look at them.


Fairly common heaters in our neck of the woods through the early 70’s. They were basic unit/space type heaters in smaller homes or multiple units in somewhat larger homes, usually built on fairly low/ limited access crawl spaces. They were fairly effective with the help of ceiling fans or other type air moving fans. In our mild climate, during most of our typical heating season they were efficient, durable and cost to operate and install was inexpensive. You saw these start to dissappear, not because of efficiency or heating capabilities, but because of the demand for A/C due to our summer cooling needs. I have replaced and even installed a couple in a new house during the early 1990’s due to efficiency, compact installation requirements and the biggest reason was they still work when the power goes off during our occassional “Ice Storms”. They still offer operation off a self-generating “Millivolt T’stat system” and no other electrical is required to operate the heat.
As far as I know, someone still manufactures these type units, probably for there simplicity.


To follow up, Yahoo or Google “Cozy Floor Furnaces”. I haven’t done so yet, but I know they were still making them in the 1990’s.

Thanks All!

I will post a picture if I find anything interesting.


Yes They still make floor furnaces can be purchased in most heating and cooling supplies but have to order then they are not a stock item.

They are very common in my area not that I like them always did not like to work on them as it always required to be in a crawl space. There is an observation hole below the grill in the top of the heat exchanger to observe the flame and to light the pilot light you have to have a long rod with a match clamp on the end to reach the pilot. It is a pain??? This observation hole has a removable cover attached normally with a small chain. This cover has to be in place to prevent CO from entering the living area.

My biggest concern would be the vent; most that I find have the vent rusted out under the home or the vent does not have proper rise from the bottom of the furnace take off to where it exits the foundation. I find numerous vents that are metal round pipe from the furnace to a vertical riser that is the old asbestos oval pipe traveling thru the attic to the roof from the crawl space.

Most of the old ones were as Greg stated Millivolts but quite common to find the gas valves updated to a 24 volt system due to problems with Millivolt wiring from the gas valve to the thermostat. Millivolts will drop if the wire connections are not soldered at any splices that may be present

oval asbestos vent pipe, floor vent get very hot- safety issue, recommend review due to heat exchanger age…

Good call Greg,

here is their website, and yes they still make them:


Interestingly they make several other forms of space heater that I have inspected brfore, but never new whose they were.



I’ve inspected hundreds in old homes in Los Angeles. They are obviously only found in older homes, commonly in the middle of a wall, drafting into a living room room on one side and a hallway on the other (to serve the bedrooms). They may be manual or thermostatically controlled. They’re subject to lint build-up around the combustion chamber, and usually have a little Mica veiwing port, which if cracked or broken poses a health hazard. They typically vent through a Transite pipe (asbestos-containing-material–asbestos content that is not easily released), and generally pass through an attic. I describe them in detail, point out that heat vents that pass through attics should be double-walled (type-b) for safety purposes. Old is not always bad, but typically is when it comes to HVAC components, and we should never forget that carbon monoxide kills. Always ere on the side of caution.

We have the same one hundred here but in the wall upright we call then wall furnaces. The old floor furnaces have the grate in the floor that you can stand on and burn your feet. If you try to stand on them bare footed you will get nice little square burn marks on your feet. Could always tell who had been standing on the floor furnace to long by looking at the bottom of their shoes??? The old floor furnaces were never safe for small children.

Thanks for all the info. I thought I would put a few pics for all of you to see. Turns out the floor heater was the least of my concerns. This house was full of structural issues.

Thanks Again!


Sorry files were to big first time so I had to resize.

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314 riggs 076.jpg

Daniel, (or do you go by Dan?)
What is the 3rd picture? Looks pretty burnt to me.:slight_smile:
You know, now that you mention it-both the houses I inspected with in floor heaters had other major issues, also.


I go by Dan. The third picture is a rotten Rim Joist. The house has several rotten floor and rim joists.


Yes, the ones I’m referring to do indeed have floor grills, on both sides of the wall, which can be removed to allow access and a better view of the combustion chamber. A sheet of metal hangs down vertically above the unit, and a screw-type lever allows this sheet to be adjusted to divert the rising heat to one side or the other, or to be split evenly if left in the vertical position. A wall furnace of course would be built into the wall and not the floor, and it would not have a floor grill.